GHSGT SCIENCE Review Packet

PHYSICAL SCIENCE SECTION

STRUCTURE AND PROPERTIES OF MATTER

When studying for this portion of the test, be sure to review the following: Be able to describe atoms and their structure in terms of:

a. atomic mass and atomic number b. elements (atoms with different numbers of protons) c. isotopes (atoms with the same number of protons, but different numbers of neutrons) d. proton, neutron, and electron charge and locations

The properties of solutions, in terms of solutes and solvents. The GHSGT will focus on the following:

1. Understanding that atoms are composed of a nucleus encompassed by a cloud of electrons 2. Recognizing that electrons are arranged in the electron cloud in energy levels. 3. Understanding that the atomic mass of an atom is concentrated in the nucleus of the atom 4. Identifying the symbol, atomic number, and atomic mass of the first 20 elements on the

periodic table. 5. Recognizing the difference between atomic number and atomic mass. 6. Identifying the effect of differing numbers of neutrons in atoms of the same element, primarily

in the context of radioactive isotopes. 7. Differentiating among elements. 8. Understanding solutions, including describing the components of solutions as solvents and

solutes. Become Familiar with the following terms:

Element Atom Nucleus Electron cloud Energy level Electron shells Proton

Electron Neutron Atomic number Atomic mass Mass number Period Group

Solution Solute Solvent Saturated Unsaturated Supersaturated Electrolyte

THE ATOM SUBATOMIC PARTICLES Nucleus: the center of the atom, contains 99.9% of the mass of the atom, holds neutrons and protons. - Proton, p+: has a positive charge; all are identical no matter which element; mass is one amu;

the number of protons determines which element you have – also called the atomic number. - Neutron, n°: is neutral (no charge); all are identical regardless of the element; mass is one amu;

the number of neutrons of an element can be determined by: Mass Number – Atomic Number = number of neutrons number Electron Cloud-the area surrounding the nucleus, is mostly empty space, and holds electrons. - Electron, e-: has a negative charge, the mass is 1/1840 amu, in a neutral atom, the number of

electrons equals the number of protons. ATOMIC NUMBER, Z: Equals the number of protons; determines the identity of the element; if you

change the number of protons, you change the element. MASS NUMBER, A: The number of protons and neutrons combined; this number is different for each

isotope of an element. ATOMIC MASS: All masses of the isotopes of the element averaged together. It is rarely a whole

number. SUMMARY: Particle Location Charge Mass (amu) the number in a neutral atom

PROTON nucleus positive 1 same as the atomic number

NEUTRON nucleus neutral 1 mass number – atomic number

ELECTRON electron cloud negative 1/1840 same as protons in a neutral atom

PERIODIC TABLE ORGANIZATION The periodic table is organized by increasing atomic number and is read from left to right. Each vertical column is called a group or family. All elements in the same family have the same number of valence electrons (the electrons in the outermost energy level. Each horizontal row is called a period. All elements in the same period are in the same final energy level.

The Element Families

Family 1 (1A) Alkali Metal family +1 ion 1 valence electron Family 2 (2A) Alkaline Earth Metals +2 ion 2 valence electrons

Elements in the first two columns are reactive metals and form compounds easily. Family 13 (3A) Boron family +3 ion 3 valence electrons Family 14 (4A) Carbon family +4 or -4 ion 4 valence electrons Family 15 (5A) Nitrogen family -3 ion 5 valence electrons Family 16 (6A) Oxygen family -2 ion 6 valence electrons Family 17 (7A) Halogen family -1 ion 7 valence electrons The halogen nonmetals are very reactive and form compounds easily. Family 18 (8A) Nobel Gas family no ion 8 valence electrons The Noble Gases are very UNREACTIVE and stable because their outermost energy level is full. ISOTOPES

An isotope is when you have atoms of the same element that differ in atomic mass. These atoms have the same number of protons but a different number of neutrons. Mass numbers are the way you distinguish one isotope from another. Any sample of an element in nature will contain a mixture of isotopes for that element. Example: CARBON carbon-12 6 protons 6 neutrons carbon-13 6 protons 7 neutrons carbon-14 6 protons 8 neutrons Carbon-12 means this carbon has a mass number of 12. Carbon-14 and Carbon-13 atoms‘ are not as stable as carbon-12 and easily break down.

If an isotope has too many or too few neutrons compared to the number of protons, it is unstable and will undergo radioactive decay. These radioactive isotopes become different elements in an effort to become more stable.

SOLUTIONS

A solution is different from an element, a compound, or a mixture. A solution is a mixture of two or more substances where all parts are identical. The parts will not settle out upon standing and cannot be filtered. Yet, they are not chemically combined like in a chemical compound. They were just mixed together in any amount. Examples include tea, coffee, and sterling silver There are two parts to a solution, the solute (substance being dissolved) and the solvent (substance doing the dissolving). The solute is in the lesser amount and the solvent is in the greater amount. Water is called the universal solvent because it dissolves a lot of things. A solution is saturated when it is holding all the solute that is can at that temperature. So a glass of tea that has sugar sitting at the bottom of the glass is saturated because it cannot hold any more sugar in solution. The excess sugar is sitting at the bottom of the glass.

ENERGY TRANSFORMATIONS When studying for this portion of the test, be sure to review the following:

Understand radioactivity and describe the half-lives of elements Examine the phases of matter and the related atomic and molecular motion Analyze energy transformations and the flow of energy in systems Understand molecular motion involved in thermal energy changes due to conduction,

convection, and radiation. The GHSGT will focus on the following:

1. Describing the process of radioactive decay in which the unstable nucleus of a radioactive isotope spontaneously decays.

2. Calculating the amount of a radioactive substance that will remain after one half-life. 3. Analyzing graphs, tables, and other displays of data to determine the length of half-life or the

amount of materials remaining after one half-life. 4. Understanding that as temperature increases, the motion of molecules increases. 5. Describing a solid as a composition of particles closely situated in position giving a definite

shape and definite volume and that little motion occurs between particles as compared to other phases of matter.

6. Describing a liquid as a composition of particles free to move, giving a definite volume but not a definite shape and that particles have a greater range of motion as compared to solids.

7. Describing gases as a composition of particles that move more that particles of either a solid or a liquid, giving no definite volume or shape, and colliding more randomly than particles of solids or liquids.

8. Understanding that a phase change requires a gain or loss in energy. 9. Describing the two forms of energy encountered during a single energy transformation,

including chemical, heat, light, electrical, and mechanical. 10. Identifying the processes of conduction, convection, and radiation that occur during thermal

energy changes.

Become Familiar with the following terms:

Alpha radiation Beta radiation Gamma radiation Half-life Solid Liquid Gas Phase change

Melting Freezing Sublimation Vaporization Condensation Conduction Convection Radiation

RADIOACTIVITY AND HALF-LIFE HALF-LIFE Each radioactive element breaks down after a certain amount of time to become stable. This time is measured in ―half-life‖. A half-life is the time required for one half of the substance‘s atoms to break down and become stable. The half-life for a substance does not change. Some examples are carbon-14 (half-life of 5730 years) and uranium-238 (half-life of 4.5 billion years). When asked to work a half-life problem, draw the boxes, like the ones below, to help you answer the question.

All atoms are One half-life later, Two half-lives later, Three half-lives later, radioactive half are radioactive ¼ are radioactive 1/8 are radioactive RADIATION The unstable elements tend to break down spontaneously. They do not have enough ―binding energy‖ in their nuclei to hold the protons and neutrons together. Most radioactive nuclei have too many neutrons compared to their protons. These elements are said to be radioactive. Radioactivity is where rays are spontaneously produced by the nucleus of an unstable atom. It can be particles, energy, or a mixture of both. Types of Radioactive Decay:

- Alpha Particle, : Has a +2 charge; the particle is composed of two protons and two neutrons; Is stopped by skin, tissue paper. These particles are not very energetic. The atomic number drops by

two. It is sometimes written as a helium atom: He4

2

Example: When uranium (atomic number 92) undergoes radioactive decay, it gives off an alpha particle. The atomic number drops by two and it becomes the element, thorium, with an atomic number of 90.

- Beta Particle, : Has a –1 charge; comes from a neutron being given off – the neutron gives off a beta particle (negative) and a proton (positive); the beta particle leaves and the proton stays in the nucleus. Metal foil stops this particle. The atomic number increases by one. Example: When bismuth (atomic number 83) undergoes radioactive decay, it gives off a beta particle. The atomic number increases by one and it becomes the element polonium, with an atomic number of 84.

- Gamma Ray, : Has no mass or charge because it is energy. It is high-powered electromagnetic radiation and it is stopped by lead, concrete.

Uses of Radioactivity - Medicine: Radiation is used as a form of therapy for cancer. X-rays and gamma rays produced by

cobalt-60 or cesium-137. Radioactive elements can be used as tracers that can follow certain chemical reactions inside living organisms.

- Industry: Food may be exposed to gamma rays in an effort to kill bacteria and other parasites in the food in hopes to limit the number of food poisoning cases.

- Radiochemical Dating: Radioactive isotopes are used to measure fossils and other artifacts. While an organism is alive, it takes in isotopes. Once the organism dies, the isotopes do not enter the body anymore. Scientists can estimate how much of the radioactive isotope was present in the body to begin with and then determine how much is currently left. Carbon-14 is a common isotope measured.

- Too much radiation can be lethal. You are exposed to radiation every day by watching television, standing in the sun, and even standing in your basement. The goal is to not get exposed to too much radiation. Too much radiation can result in cancer or other diseases. This happens when the radioactive substance causes damage to your DNA and chromosomes. This damage to the DNA is called mutations. This in turn causes changes in your cells.

- Fuel/Electrical Source: The energy produced in nuclear reactions can be used as a fuel source. Fusion is the result of nuclei combining and giving off huge amounts of energy. This occurs in the sun. Fission is the splitting of an atom into two and releasing energy at the same time.

STATES OF MATTER

SOLID Solids have definite shape and definite volume. For the most part, solids can be carried around without the help of a special container. The molecules or atoms in a solid are densely packed together and vibrate back and forth in their own space. The atoms cannot change positions. Examples: rock, paper.

Liquids have no definite shape and a definite volume. They take on the shape of the container that they are in. The molecules or atoms in a liquid are packed together, but not as densely as a solid. They can slide around each other but cannot break apart. Examples: water, mercury. Gases have no definite shape and no definite volume. They expand to take on the shape and volume of the container they are in. A gas‘ molecules or atoms have more energy than a solid or liquid and they can go anywhere within their container. Examples: helium, air. PHASE CHANGES Each of the three main states of matter can change into another state by going through a phase change. Remember as a solid becomes a liquid becomes a gas, temperature is increasing and the molecules in the substance are moving faster. Substances are made to change phases by adding or taking away heat energy. There are six phase changes.

Melting solid becomes liquid absorbs heat Vaporization (boiling) liquid becomes gas absorbs heat ENDOTHERMIC Sublimation solid becomes gas absorbs heat Freezing liquid becomes solid loses heat Condensation gas becomes liquid loses heat EXOTHERMIC Deposition gas becomes a solid loses heat

Be sure you understand a heating curve. See below: G L Temp. S Energy

Phase changes are physical changes. Physical changes do not produce a new substance. They produce the same substance with new physical properties. For instance, water may change from a solid to a liquid. Its volume and density will change, but it is still water. Examples of physical changes include melting, freezing, condensation, vaporization, sublimation, cutting, breaking, mixing, and dissolving. Chemical properties cannot be observed unless the substance you are observing becomes something new. The particles of one substance undergo a chemical change and become something new. Chemical properties include such properties as flammability. You cannot observe this in paper unless the paper burns. Then, it is no longer paper. There are several evidences of chemical changes. We also call these chemical reactions. These are:

- Formation of a new substance (solid precipitate, gas bubbles) - The production of energy (heat or light) - The absorption of energy - Appearance of a new color or odor

Examples of chemical changes include combustion (burning), fermentation, metabolism, electrolysis, rusting – anything that involves a chemical reaction.

ENERGY TRANSFORMATIONS

Energy is the ability to do work (work involves a change in movement). Energy is the ability to cause change. The units for energy are joule, J. All matter contains some form of energy because all matter has the ability to do work or cause change. There are changes in forms of energy. This is where energy changes from one type to another. Energy cannot be created or destroyed, just converted from one form to another. When you rub your hands together, mechanical energy (moving your arms) turns into heat energy in your hands due to friction. MECHANICAL associated with motion. Ex. waterfall, sound, running. HEAT internal motion of particles of matter. The faster the particles move, the more

heat energy is present Ex. rubbing hands together. CHEMICAL stored in bonds that hold atoms and ions together. Ex. fire, energy to move

muscles ELECTRICAL moving electrical charges. Ex. lightning, radio

LIGHT visible portion of the electromagnetic radiation

Examples of Changes from One Form of Energy to Another

Chemical to electrical Flashlight battery Electrical to heat toaster Electrical to sound telephone, door bell Electrical to chemical human sight Electrical to mechanical turning on a ceiling fan Chemical to mechanical energy in food helping your arms move to throw a ball Mechanical to electrical water turning a turbine which then moves a magnet to generate

electricity

HEAT TRANSFER

Heat is energy, sometimes called thermal energy. The heat of an object is the total kinetic energy of the random motion of its atoms and particles. When a substance is heated, its molecules move faster and further apart. Heat is always transferred from the hotter object to the cooler object. Dark colored objects absorb more heat than light colored objects. That is the reason tennis players wear white! Conduction: Heat is transferred from one object to another by direct contact. The two substances must be touching. An example of conduction is the hot chocolate heating the cup it was poured into. Substances that are conductors transfer heat very easily - iron, copper, and aluminum. Insulators slow down the conduction of heat - air and glass. Convection: Heat is transferred through currents of liquids and gases. As a fluid gets warmer, its molecules spread out and become less dense. This fluid will rise because it is now less dense than the fluid on top of it. As it rises, colder fluids fall. This cycle forms a current of warm rising fluid and cold falling fluids. This is called a convection current. Water circulating in the oceans or world wind currents are examples of this type of heat transfer. Radiation: This type of heat transfer requires no matter. Radiant heat is the transfer of energy by electromagnetic (infrared) waves. Examples of radiation are when you feel the heat from the fire or the sun‘s heat

FORCES, WAVES, AND ELECTRICITY

When studying for this portion of the test, be sure to review the following:

a. Understand the relationship between force, mass, and motion. a. Calculate velocity and acceleration b. Apply Newton‘s First Law of Motion, the law of inertia.

c. Relate falling objects to the force of gravity d. Understand the difference between mass and weight. e. Calculate work and mechanical advantage

b. Describe the properties of waves a. Understand that all waves transfer energy b. Associate frequency and wavelength with the energy transferred by electromagnetic and

mechanical waves. c. Understand the concepts and can identify examples of reflection, refraction,

interference, and diffraction. d. Analyze the effects of different mediums on the speed of sound.

c. Understand the properties of electricity and magnetism a. Describe magnetism and electrical charges in the context of electricity, magnetism,

electromagnets, and simple motors. Assessment will focus on the following:

1. Using the following formulas to solve for velocity and acceleration: vf - vi

Velocity: v = d/t Acceleration: a = T

2. Apply knowledge of Newton‘s First Law of motion to give situations: a. An object in motion stays in motion unless acted upon by an unbalanced force. b. An object at rest remains at rest unless acted upon by an unbalanced force.

3. Understanding that gravity causes objects to accelerate as they fall. 4. Understanding factors that affect the force of gravity on an object. 5. Explaining the difference between mass and weight. 6. Calculating work using the formula W = f d (Work = force x distance) 7. Understanding the concept of mechanical advantage in relation to simple machines 8. Understanding that waves carry energy 9. Relating frequency and wavelength to the energy carried in waves 10. Understanding how frequency and wavelength are related. 11. Understanding that electromagnetic waves do not require a medium 12. Understanding how electromagnetic waves differ in the amount of energy transferred based on

position in the electromagnetic spectrum. 13. Relating frequencies and wavelengths on the electromagnetic spectrum to technological

advances such as microwaves and radio waves. 14. Understanding how light interacts with lenses and mirrors 15. Using the terms absorption, reflection, refraction, interference, and diffraction to describe how

waves (including sound waves) interact with obstacles, within mediums, and with other waves. 16. Describing how the speed of sound varies with the type of medium and temperature of a

medium. 17. Relating magnetism and electricity. 18. Describing electromagnets, including their uses in electric motors, generators, radio, television,

and other technologies.

Become Familiar with the following terms:

Gravity Force Inertia friction Mass Weight Work Power Speed

Velocity Acceleration Simple machine Wave Wavelength Frequency Reflection Refraction Electric current

Static current Electric circuit Conductor Insulator Electromagnet Wet cell Dry cell Ohm‘s Law

FORCES A force is a push or pull that starts, stops, or changes the direction of an object. Force transfers energy to an object. To determine the amount of force being used, you need the mass of the object and its acceleration. Force is measured in Newtons, N.

The equation is: Force = mass x acceleration Forces that are in opposite directions and equal in size are called balanced forces. The larger arrow indicates in which direction the object will move. + = + = 0 If the two forces are exerted in the same direction, When forces are balanced, there is no change they combine and should be added together (A). in motion (B). + =

If the forces are exerted in exactly opposite directions and are not equal in size, then you must subtract the smaller force from the larger to get the net force (C).

Friction is a force that opposes motion. It slows down an object. Motion of an object is going to occur when the forces acting upon it are unbalanced, like in Figure C. One force cancels out the effects of a smaller force. There are three types of friction: fluid friction, rolling friction, and sliding friction. Fluid friction has the least amount of force and sliding has the most.

A B

C

NEWTON’S FIRST LAW (Law of Inertia) Newton‘s first law states that an object in motion will remain in motion and an object at rest will remain at rest unless acted upon by an unbalanced force. An object placed on a desk stays there until someone or something pushes it off. A ball thrown in space will continue forever until it hits something. Objects tend to keep on doing what they're doing. In fact, it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia. Inertia is the resistance an object has to a change in its state of motion. The more mass an object has, the more inertia an object has. An object with a lot in inertia is difficult to get moving and also harder to stop once it is moving. A ball thrown on earth will not keep going forever. The ball thrown on earth is acted on by gravity and friction. So it slows down and falls to earth. Gravity and friction are the unbalanced forces. GRAVITY The universal Law of Gravitation states that every object in the universe is attracted to every other object in the universe. This force of attraction depends on the mass of the two objects as well as the distance that separates them. The more mass it has, the greater its gravitational force. The closer the two objects are, the greater the gravitational force. On earth, when you let go of an object, it falls to the ground at 9.8m/s2. This is acceleration due to gravity. Objects accelerate as they fall due to gravity. Gravity is measured by weight and the unit is the Newton, N. If you change the force of gravity, you will change the weight. Keep in mind that the amount of matter – the mass – does not change - only the force that is pulling on that matter changes and this is reflected in a change in weight. Weightlessness occurs when the force acting upon an object is equal and opposite to the force of gravity. WORK Force is needed to move an object and in doing so, work is done. In order for work to be done, you must be lifting something. Lifting a book is work. Simply carrying the book across the room or holding the book above your head is not considered work.

The equation is: Work = Force x distance The unit for work is joules (Newton-meter).

MACHINES Simple machines help us make better use of our muscle power to do work. A Machine produces force and controls the direction of force, it cannot create energy. Simple Machines help us lift, pull, increase elevation of heavy things, change the direction of the force, increase the force, split things, fasten things, and cut things. We all use simple machines everyday, opening a door, turning on the water faucet, going up stairs, or opening a can of paint. Bottom Line: They are simple devices used to make work easier.

Remember work is calculated by force times distance. If you change force or distance, the amount of work will change. EFFORT FORCE is the amount of force that is applied to the machine by you. The force opposing the effort force is the RESISTANCE FORCE - often the weight of the object. Mechanical advantage is the number of times a machine multiplies force. It is the ratio of the force that comes out of a machine to the force that is put into the same machine. The formula for mechanical advantage is:

Actual mechanical advantage = resistance force effort force. The formula for ideal mechanical advantage is calculated by:

Ideal mechanical advantage = effort length resistance length

There are six simple machines. One group includes the inclined plane (ramp), the screw, and the wedge. The second group includes the pulley, the wheel and axle, and the lever. A compound machine is a combination of two or more simple machines. The mechanical advantage of a compound machine is greater than that of just one simple machine. Example: mechanical pencil sharpener - inclined plane, a wheel and axle. MOTION In order for motion to occur, there must be unequal forces. To measure motion, calculate the speed of

the object. The formula for speed is: Speed = distance time

The speed and direction of an object‘s motion is called velocity. Constant speed means that the object is not changing its motion. Average speed can be calculated by taking the total distance traveled divided by the total time elapsed. Velocity is speed in a particular direction. There are times when an object needs to change its velocity. This is done by slowing down or speeding up. Once motion gets started, unequal forces allow for speeding up or slowing down. ―Speeding up‖ is called acceleration. Negative acceleration is called deceleration (―slowing down‖).

The formula for acceleration is: Acceleration = (final velocity – starting velocity)

. Projectile Motion is the motion of a thrown ball. The ball initially curves up or stays straight and then

arcs back down to the surface. This arcing motion is due to gravity pulling down and friction slowing it down.

WAVES

A wave is a disturbance that transfers energy through matter or through space. Some waves, like sound waves, must travel through matter while others, like light, can travel through space and do not need a material to move through. Energy is transferred to nearby particles and they move, causing other particles to move. Energy is transferred from one place to another. The particles of matter do NOT move along with the wave. ONLY the energy that produces the wave moves with the wave.

Waves can be compressions of energy (compression / longitudinal wave) or made up of up and down movements (transverse wave). An example of a compression wave is sound. Examples of transverse waves include water waves and earthquakes. Parts of a Wave:

A. Amplitude - the height of a wave above or below the midline

B. Crest - the peak or top of the wave C. Midline - original position of the medium before the

waves move through it. D. Trough - the lowest point of the wave E. Wavelength (cycle) - the distance between two peaks.

Relating Frequency and Wavelength Frequency is the how fast the wave is moving. If you stand in one spot and watch a wave go by, it is the number of crests that go by in a second. A long wave (one that doesn‘t have too many crests and has a long wavelength) has a low frequency. A short wave (one that has a lot of crests or a short wavelength) has a high frequency. The higher the frequency, the more energy a wave has. Waves with short wavelengths have more energy than larger wavelengths. The speed or velocity of a wave depends on the wavelength and the frequency. The formula for wave speed is: Speed = wavelength x frequency THE ELECTROMAGNETIC SPECTRUM The electromagnetic spectrum is an order of electromagnetic waves in order of wavelength and frequency - a long wavelength has a low frequency, a short wavelength has a high frequency. Electromagnetic waves can travel through space. They do not need to travel through a medium like air or water, though they can. The Spectrum in Order

Radio Waves lowest frequency and longest wavelength, used for communication (radio and TV) Microwaves used in cooking and for RADAR Infrared Waves cannot be seen, felt as heat, ―below‖ red, used for cooking, medicine, night

sight Visible Light portion of the spectrum that your eye is sensitive to, consists of seven colors

(ROYGBIV), red has the lowest frequency/energy and violet has the highest frequency/energy

Least E

Most E

Ultraviolet Waves present in sunlight, ―beyond‖ violet, energy is enough to kill living cells, used for sterilization

X-Rays energy is enough for photons to pass through the skin, for medicine highest frequency, shortest wavelength, certain radioactive materials emit

them, have Gamma Rays tremendous ability to penetrate matter, used in the treatment of cancer

WAVE INTERACTIONS When a wave hits a piece of matter, the wave can be absorbed or it can be reflected.

Reflection the bouncing back after a wave strikes an object that does NOT absorb the wave‘s energy. The Law of Reflection states that the angle of the incidence is equal to the angle of

reflection. In other words, the angle that it hits the object at will be the same angle, in the opposite direction, that the waves leaves the surface.

There are three types of mirrors that reflect light. PLANE - flat surface, reflected image is the same size. CONCAVE - curves inward, like the bowl of a spoon, reflected image is either enlarged (original image was close to the mirror ) or the reflected image is smaller and upside-down (original image was far away). CONVEX - curves outward, like the back side of a spoon, reflected image is always smaller and right side up, provide a wide angle of view so a large area can be seen.

The reflection of sound is called an ECHO. Refraction The bending of waves due to a change in speed. This time the wave is absorbed and not

reflected. Waves move at different speeds in different types of matter. Temperature can also affect the

speed of a wave. Examples include prisms (bends white light into its component colors), lenses like glasses and

contacts, and a mirage. Diffraction The bending of waves around a barrier. When a wave encounters a barrier, it can go around it. Electromagnetic waves, sound waves, and water waves can all be diffracted. Diffraction is

important in the transfer of radio waves. Longer AM wavelengths are easier to diffract than shorter FM wavelengths. That is why AM reception is often better than FM reception around tall buildings and hills.

Examples include rainbow glasses, diffraction gratings. Interference The phenomenon which occurs when two waves meet while traveling along the same medium.

The interference of waves causes the medium to take on a shape which results from the net effect of the two individual waves.

When two waves‘ crests or troughs combine, there is an additive effect – this is called constructive interference. When one wave‘s crest and another‘s trough combine, there is a subtractive effect – this is called destructive interference.

Constructive interference Destructive interference SOUND Sound moves from its source in the form of compression waves. Sound is a form of energy that causes the molecules of a medium to vibrate back and forth. Sound cannot travel through space or a vacuum. Materials that can easily bounce back (elastic) transmit sound easily. Solids are generally more elastic than liquids or gases because the molecules are not very far away and bounce back quickly. Elasticity increases the speed of sound; If the objects are in the same phase (ex. both liquids), sound goes slower in the denser medium. As temperature increases, the speed of sound increases. Sound travels faster at higher temperatures. DOPPLER EFFECT This is a common occurrence that depends on the frequency of sound (or light) waves. There is a change in pitch whenever there is motion between the source of the sound (or light) and its receiver. Either the source of the sound or the receiver must move relative to the other. Consider an ambulance siren moving towards you. Each time the siren sends out a new wave, the ambulance moves ahead in the same direction as the wave. This gives shorter wavelengths and higher frequencies because the waves get pushed together. So, the pitch goes up. As the ambulance passes you, it is traveling in the opposite direction and the waves spread out. Wavelength gets longer, frequency gets lower, and the pitch goes down. This also happens with light when light from a star is being sent back to earth. If the star is moving away relative to the earth, the light gets shifted to the red side of the spectrum, called a red shift.

ELECTRICITY AND MAGNETISM

METHODS OF GENERATING ELECTRICITY Electricity is a form of energy called electrical energy. It is basically moving electrons. It can be produced in several ways. Static Electricity - This is a build up of electrical charge when electrons are exchanged from

one object to another. Once they move to another object, they remain on that object. Static electricity is a result of friction. Friction separates electrons from the surface of an object whose atoms hold electrons loosely. Some good ways to generate static electricity are to rub opposite substances together like silk and glass or plastic and wool.

Electric Current - This is a streams of electrons that flow through a conductor, like a wire. An electric current can be produced chemically, by moving water (hydroelectric), by solar cells (using sunlight), by wind, and by nuclear radiation (fission reaction).

a. Chemical energy comes from a wet cell or a dry cell battery. It changes chemical energy into electrical energy. It is a reaction that is produced as atoms within a substance exchange, transfer, or lend electrons to another atom within the substance of the cell. An electric cell contains two electrodes, two different substances. In a wet cell, the electrodes are put in an electrolyte (liquid that can carry an electric current). The electrodes react with the electrolyte solution and release electrons. Electrons move from the negative electrode to the positive electrode through a wire. A dry cell works that same way except there is a solid paste, like ammonium chloride, instead of the liquid electrolyte.

b. Hydroelectric power, nuclear energy and wind energy are generated through electromagnetism. The moving air or water turns a turbine. The turbine moves a magnet through a coil of wire. This is called electromagnetic induction. Electromagnetic induction is the process of inducing an electric current by moving a magnetic field through a wire coil without touching it – this is what a generator does and this is how water produces electricity.

INSULATORS AND CONDUCTORS Conductors are materials that are good at carrying an electric charge. Insulators keep an electric charge from flowing. Good conductors of electricity include metals, water, electrolytes (solutions containing ions), and the human body. Good insulators include nonmetals, rubber, plastic, and wood. Sometimes an insulator and a conductor are put together to keep electricity flowing in a particular direction. A copper wire is coated in plastic to protect anyone from getting electrocuted when they touch the wire. ELECTRICAL UNITS There are three ways to measure electricity. They are current, voltage, and resistance.

1. Current: This is the rate at which electric current flows through a wire. It is the number of electrons that pass by a specific point in a circuit in one second. The symbol is ―I‖ and is measured in amps (A).

2. Voltage: Electrons need energy to force the electrons through the wire. Voltage is the amount of energy available to move the electrons. The higher the voltage, the more work the electrons can do. The symbol for voltage is ―V‖ and it is measured in volts (V).

3. Resistance: This is the measure of how difficult it is to move electrons through a circuit. It is the force opposing the flow of electrons. Good conductors have a low resistance and poor conductors have a high resistance. Resistance depends on the material‘s length, thickness, and temperature. The symbol for resistance is ―R‖ and it is measured in ohms ( ).

Ohm‘s Law relates current, resistance, and voltage: Current = voltage resistance

MAGNETISM Magnetism is a universal force like gravity. A magnet always has two poles - north and south. Like poles repel each other and opposite poles attract. There is a magnetic field around a magnet and the invisible lines of force run from one pole to the other. See below – iron filings show the magnetic lines of force.

A magnetic field can be produced using a current through a wire and a piece of metal that can be magnetized. Electricity and magnetism are related. Electricity can produce a magnetic field and magnetism can produce an electric current. ELECTROMAGNETISM An electromagnet is a temporary magnet. As long as there is a current flowing, a magnetic field is present. A simple electromagnet consists of a battery, copper wire, and an iron nail. The strength of the electromagnet depends on the number of turns in the wire coil and the size of the iron core. The greater the number of turns, the stronger the magnetic field that is produced. Magnets are used in electric motors. An electric motor is a device that produces a direct current. It contains an electromagnet, a permanent magnet, and a commutator. The electromagnet is placed between the poles of the permanent magnet. The poles repel and attract each other and the electromagnet spins. Electric energy is converted into mechanical energy. This is the opposite of a generator. Magnets are also used in television sets. The non-plasma televisions all have a cathode ray that uses electrons and fluorescent materials to produce images on a screen. An electromagnet changes the path of the beam of electrons which allows it to sweep the television screen many times a second. A transformer is a device that uses electromagnetic induction to change the voltage of a current. Transformers are basically iron cores with wires wrapped around them. There are transformers at the power plant, at power substations, and on the utility pole near your house. The one near your house looks like a trash can on the utility pole. A transformer works by stepping up or stepping down the voltage of electricity. More current in a wire means that more energy is wasted due to resistance in the wire. Power companies want to limit the amount of energy wasted. When energy is transmitted over a long distance, the voltage is raised and the current is lowered. The step up transformer raises the voltage. For instance a power plant will step up the voltage from 20,000 volts to 250,000 volts to run the electricity through the long distance transmission lines. The primary coil has a certain number of turns with the wire. If the secondary coil has twice as many turns as the primary coil, the voltage will be twice as much in the secondary coil.

18

LIFE SCIENCES SECTION

CELLS AND HEREDITY When studying for this portion of the test, be sure to review the following: 1. Describe the structures of cells and the structure of their components.

a. Examine the similarities and differences between prokaryotic and eukaryotic 2. Explain the process of inheritance of genetic traits.

a. Differentiate between DNA and RNA, recognizing the role of each in heredity. b. Demonstrate understanding of Mendel‘s Laws in genetic inheritance and variability. c. Discuss the use of DNA technology in the fields of medicine and agriculture.

3. Analyze the similarities and differences between organisms of different kingdoms. Assessment will focus on the following:

11. Describe the roles of cell organelles in the following: a. information feedback b. motility c. obtaining, storing, and using

energy

d. protein construction e. reproduction f. transport of material g. waste disposal

12. Differentiating the functions of the macromolecules: a. carbohydrates b. lipids

c. nucleic acids d. proteins

13. Understanding differences between DNA and RNA 14. Describing how DNA stores and transmits information 15. Understanding Mendel‘s Laws as they apply to variability between generations and cell division. 16. Understanding how DNA technology is used today in medicine and agriculture, including, but

not limited to: a. Environmental factors in mutation b. Genotype and phenotype

17. Understanding the relationships between single-celled and multi-celled organisms, on a broad conceptual level.

18. Differentiating how organisms from different kingdoms obtain, transform, and transport energy and/or material.

Become Familiar with the following terms:

Cell Response Stimulus Prokaryote Eukaryote Cell wall Cell membrane Cytoplasm Vacuole Mitochondrion

Chloroplast Nucleus Chromosome Endoplasmic reticulum Golgi bodies Ribosome Homeostasis Isotonic

Hypotonic Hypertonic Osmosis Diffusion Carbohydrate Lipid Nucleic acid Protein Double helix

Replication Translation Transcription Photosynthesis Respiration ATP Mitosis Meiosis Interphase Prophase

Metaphase Anaphase Telophase Genetics Heredity Dominant Recessive Homologous Alleles Gametes

19

Species Trait Genotype Phenotype

Nondisjunction Punnett square

Kingdom Phylum Class Order

Family Species Genus Pollen

Pollination

THE SIGNIFICANCE OF BIOLOGY Biology is the study of life and living organisms. An organism is a complete, individual, living thing. All organisms are formed from the same basic building block – cells. Most cells are so small that you cannot see them. Cells are not only the structural units of living things, they are the functional units as well. They are the smallest units that carry on the activities of life.

DIVISIONS OF BIOLOGY

Originally, there were two fields of biology, only botany and zoology. Now there are many. Here are a few:

1. Anatomy - The study of the external and internal structures of organisms. 2. Biochemistry - The study of the chemical make-up and processes of organisms. 3. Botany - The study of plants. 4. Cell Biology - The study of the structure and activities of living cells. 5. Ecology - The study of how organisms interact with one another and with their environments. 6. Evolutionary Biology - The study of how organisms have changed throughout time. 7. Genetics - The study of heredity, or how traits are transmitted from one generation to another. 8. Immunology - The study of infection protection 9. Microbiology - The study of organisms too small to be seen without a microscope. 10. Physiology - The study of how organisms carry on their life processes and how various parts of

the organisms perform their special functions. 11. Zoology - The study of animals.

CHARACTERISITICS OF LIVING THINGS

1. Organisms are highly organized. Every living cell is a highly complex structural and chemical system.

2. Organism use energy. All living things need energy because they are constantly building the substances that they need. The sum of this chemical building up and breaking down is known as metabolism.

3. Organisms grow and develop. 4. Organisms cannot live forever. 5. Organisms reproduce themselves. 6. Organisms respond to stimuli. Any condition to which an organism responds to is called a

stimulus. What an organism does as a result of the stimulus is a response. The ability to respond to stimuli is typical of all living organisms. This property is called irritability.

7. Organisms adjust to their environment. To survive, an organism must adjust to changes in its environment. Any change in an organism that makes it better suited to its environment is called an adaptation.

THE CELL THEORY 1. All organisms are composed of cells. (Schleiden and Schwann) 2. Cells are the basic units of structure and function in organisms. (Schleiden and Schwann) 3. All cells come from preexisting cells. (Virchow)

The virus does not fit this theory. It is a packet of nucleic acid wrapped in a protein coating. It possesses only a few structures of a cell. It relies on a host cell to help it reproduce. It cannot reproduce on its own.

DIFFERENCES IN CELLS

Cells can be grouped according to their similarities and differences. All cells can be divided into two categories – prokaryotes and eukaryotes. A PROKARYOTE is a cell that lacks a true nucleus and does not have membrane-bound organelles. The DNA in a prokaryote is a single circular molecule. They have no mitochondria, chloroplasts, Golgi bodies, lysosomes, vacuoles, or endoplasmic reticulum. They do have a cell wall and a cell membrane. Bacteria and blue-green algae are prokaryotes. A EUKARYOTE is a cell that possesses a well-defined nucleus surrounded by a nuclear membrane. The DNA is in the form of complex chromosomes. The organelles are membrane bound. There is a greater division of all the jobs to be done in an eukaryotic cell. These cells are found in plants, animals, fungi, and protists. Eukaryotic cells also differ between plants and animals. Plant cells contain three structures not found in animal cells – cell walls, large central vacuoles, and plastids. Centrioles are found in some, but not all types of plant cells. They are found in all animal cells.

Plant Cell

Animal Cell

STRUCTURE AND FUNCTION OF CELLS Cells differ in size, shape, and function. But most share several common traits. There are two main types: animal and plant. Both of these cell types have the following ORGANELLES (cell structures): Nucleus: controls the activities of the cell and holds the DNA. The ―brain‖ of the cell. Cytoplasm: gel-like substance inside all cells in which most of the cell‘s life processes take place. Chromosomes: contain complex genetic information that directs all the cell‘s activities. Located in the

nucleus. Cell membrane: outer covering of the cell. It regulates what enters or leaves the cell and it allows for

all the communication between cells. Mitochondria: supplies the energy that the cell needs to do work. They release this energy from the

nutrients taken up in the cell. Endoplasmic Reticulum (ER): transports proteins from one part of the cell to another. It is the internal

support system for the cell. There are two types – rough ER (contains ribosomes) and smooth ER (no ribosomes)

Ribosome: Attached to ER, they make the proteins. Ribosomes are located either on the endoplasmic reticulum or free within the cytoplasm of the cell.

Lysosomes: storage containers that hold enzymes that break down larger food molecules into smaller ones.

Golgi Bodies areas for the storage and packaging of chemicals. They are formed from pinched off ER. They look like flattened balloons.

Microtubules long, slender tubes that hold the cells more rigid. They support the cell and maintain its shape.

Spindle Fibers microtubules that appear during cell division. These are temporary structures that help guide the chromosomes through the cytoplasm.

Centrioles small dark bodies located outside the nucleus in many cells. They exist in pairs and perform a function only during cell division. They appear only in animal cells.

Cilia short, threadlike projections that stick out on the surface of the cell. They aid in locomotion as well as moving substances along the surface of the cell.

Flagella Long hairlike projection that sticks out on the surface of the cell. There are usually just one or two per cell. They aid in the locomotion of unicellular organisms.

Plant cells also have: Cell wall: rigid wall that supports and protects the cell and is located outside the cell membrane. Chloroplasts: stores chlorophyll. It allows plants to make their own food by converting light energy

into chemical energy. Vacuole: storage containers for food, water, and other materials. Not all animal cells have

vacuoles. The interior of plant cells has one large one. Plastids: storage containers that hold food or pigments. CHANGING TO STAY THE SAME An important property of living things is the ability to maintain a nearly constant internal environment. This is important because cells are extremely delicate. Cells cannot tolerate a change in temperature and the surrounding concentration of chemicals cannot change much. Cells might shrivel up like raisins

or swell and burst. You can compare the maintenance of the cell‘s environment to that of a greenhouse. The internal environment of a greenhouse is maintained so that the conditions are favorable for plant growth. Not only do cells have to adjust to a changing environment, but they also have to adjust to the activity of the moment. They may need to produce extra fuel to help your muscles run a race, they may have to make your lungs and heart work harder, and they may have to release extra heat generated by the hard work of these cells. Keeping this delicate balance is called HOMEOSTASIS. This is a self-adjusting balance of all the life functions and activities.

THE MOVEMENT OF MATERIALS

When we study cells, we are primarily concerned with the movement of molecules in a liquid. All the substances important to life are often part of a solution. A solution is a mixture where the molecules of one substance are evenly spread out in the molecules of another. The substance that makes up the greater part of the solution (or the substance doing the dissolving) is called the solvent. The molecules in the smaller amount (or the substance being dissolved) are called the solute. In salt water, water is the solvent and the salt is the solute. Water is the solvent of most solutions involved in cell activities. DIFFUSION is the process by which molecules of a substance move from area of higher concentration to areas of lower concentration. Think of a drop of food coloring in a beaker of water. The drop is initially very concentrated. Gradually the color molecules move throughout the whole beaker of water until the entire beaker is the same color. The net, or overall, movement of the molecules results in a uniform concentration of food coloring throughout the whole beaker. Diffusion is one of the major mechanisms of molecular transport in cells. Many materials move into, out of, or through the cells due to diffusion. The difference between the concentration of molecules of a substance from the highest to the lowest concentration is called a diffusion gradient. Molecules move from the higher area of concentration to the lower area along this concentration gradient. The steeper the gradient, the faster diffusion occurs. OSMOSIS is how water diffuses into a cell. Osmosis is the diffusion of water through a membrane. The cell membrane controls what enters and leaves the cell. They are selectively permeable. This means they allow only certain substances to pass through them into or out of the cell. The cell membrane is a lipid bilayer with proteins planted in it. Oxygen and carbon dioxide can pass right through the membrane, but water cannot. Water and other molecules that cannot dissolve in lipids pass through the cell through openings made by proteins in the membrane. Water diffuses into cells by osmosis. Water makes up 70-95% of a cell. Since water is the most abundant substance in cells, its movement into and out of the cell is very important. The cell has no control over osmosis. It occurs due to differences in concentrations inside the cell and outside the cell. Water will move back and forth across the cell membrane until equilibrium is reached. Water molecules will always move to the area where they can make the water purer or ―fresher‖.

In an ISOTONIC solution, the concentration of solutes outside the cell is the same as the concentration inside the cell. They are equal. Freshwater plants often exist in HYPOTONIC solutions. In hypotonic solutions, the concentration of solutes outside the cell is lower than that inside the cell. "―Hypo-"―means less than, so there is less outside the cell. As water flows into the cell, the cell swells and

increases its internal pressure. (The cell inside has less fresh water, so the fresh water moves into the cell to try and make it more ―fresh‖.) This is called turgor pressure (pressure built up as a result of osmosis). Excess water is often stored in the large central vacuole. The cell pushes against its cell wall and the cell stiffens. This causes the plant to become more rigid. In animal cells, if water flows in unchecked, the cell will swell and burst. An example of this would be a red blood cell bursting when placed in fresh water. Cells have ways to get rid of the excess water. Unicellular organisms have a contractile vacuole which pumps excess water out of the cell. Freshwater fish remove excess water through their gills.

In a HYPERTONIC solution, cells can shrivel up because more water flows out of the cell than into it. In a hypertonic solution, the concentrations of the solutes outside the cell is greater than that inside the cell. ―Hyper-― means more than, so there is more outside. Drinking seawater is dangerous to humans because the ocean is hypertonic with relation to the human body. Drinking salt water causes the body‘s cells to lose water through osmosis. The cells lose more than they take in. OTHER MEANS OF TRANSPORT Carrier molecules are proteins in the cell membrane that transfer large molecules or molecules that cannot dissolve in the lipids that make up the cell membrane. They pick up

molecules on one side of the membrane and carry them across to deposit them on the other side of the membrane. Facilitated diffusion involves the use of a carrier molecule but follows the rules of simple diffusion – the molecules will move from an area of higher concentration to an area of lower concentration. The carrier molecule speeds up the diffusion process. The cell does not expend energy in this process. Active transport is another transport method using carrier molecules. Active transport is the movement of materials against the concentration gradient. In active transport, molecules are moved from an area of low concentration to an area of high concentration. This process requires energy.

ORGANIC COMPOUNDS There are six elements that are especially important to life: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (CHNOPS). There are about twenty others that play lesser roles. Iron, iodine and other trace elements make up less than 0.1% of the human body, but must be present for the body to function normally. Carbon forms the backbone of all organic molecules. Only carbon is versatile and stable enough to make up the tremendous variety of molecules that are found in living things. There are four main types of molecules containing carbon. CARBOHYDRATES are organic compounds that contain carbon, and hydrogen and oxygen. Carbohydrates that you are familiar with are sugars and starches, such as glucose and cellulose. Carbohydrates like cellulose are used as structural materials. Carbohydrates like glucose provide quick energy or store energy in cells. The largest carbohydrates are called polysaccharides. These molecules consist of hundreds of units of glucose or simple sugars. Plants store food in the form of starch, a polysaccharide of glucose. Animals store excess sugars as glycogen, another polymer of glucose. Cells break down glycogen or starch and energy is released. LIPIDS are a chemically diverse group of substances that include fats, oils, and waxes. Examples include butter, beef fat, and olive oil. Lipids also contain carbon, hydrogen, and oxygen like carbohydrates, but lipids are more complex than carbohydrates. All lipids are insoluble in water. They serve mainly as storage of energy in living things. They provide the most stored energy and usually have the most calories. Lipids are also part of the cell membrane and thus help regulate what enters and leaves cells. Many lipids have a backbone that is a three-carbon molecule called glycerol to which three fatty acids are attached. PROTEINS are basic building materials of all living things. Protein molecules contain carbon, hydrogen, and oxygen. But unlike carbohydrates and lipids, they also contain nitrogen, sulfur, and other elements. All proteins are made of monomers (single molecules) called amino acids. Examples of proteins include egg whites, gelatin, and hair. There are 20 amino acids. These amino acids combine to form polypeptides. All proteins consist of polypeptides. NUCLEIC ACIDS are a class of organic compounds that carry all instructions for cellular activity. There are two kinds of nucleic acids. Deoxyribonucleic acid, DNA, records the instructions and transmits them from generation to generation. Ribonucleic acid, RNA ―reads‖ the instructions and carries them out. ENERGY FOR LIVING CELLS Cells require chemical energy to make tasks necessary for life. This energy is stored in the form of chemical bonds between atoms in food. The energy is taken from the food and stored in molecules that can provide the energy where it is needed in the cell. Many reactions in the body energy to keep them going (endergonic). In most cases, a molecule called ATP (adenosine triphosphate) provides this energy. ATP consists of a sugar, base, and a chain of three

ATP

ADP

P P

phosphates. The bond that holds the second and third phosphate together is easily broken. Enzymes help ATP to transfer this phosphate to another molecule. When this transfer takes place, energy is released that drives the chemical reactions in a cell.

For ATP to be effective, it must lose its final phosphate. The phosphate is returned to ATP by adding a phosphorus (P) to ADP. The series of reactions between ATP and ADP form a cycle. See the diagram to the right. Think of it as a battery that is continually recharging itself. The phosphate group is returned to ATP during a process called cellular respiration. Glucose is broken down and the energy in its bonds is transferred to the energy bonds of ATP. PHOTOSYNTHESIS

The ultimate source of the energy that powers cells is the sun. Green plants and other organisms (AUTOTROPHS) capture the light energy of the sun through the process of photosynthesis. Photosynthesis requires light, chlorophyll, and raw materials. Enzymes are also needed for the reactions to proceed. Chlorophyll in the plants traps the light of the sun. Carbon dioxide from the air and water from the ground are the raw materials for the process of photosynthesis. Glucose is the end product. Oxygen and water are also given off.

enzymes,

light, chlorophyll

6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O

The purpose of photosynthesis is to store the energy of the sun in the bonds of the glucose molecules. These molecules are then used by organisms to provide energy for cellular activities. The energy is removed from the glucose in a process called respiration.

RESPIRATION Cellular respiration involves breaking the chemical bonds of organic food molecules and releasing energy that can be used by the cells. The food molecules were the ones produced in plants during the process of photosynthesis. Respiration involves several steps. Glycolysis is the first step where glucose is broken down into a compound, pyruvic acid, and energy for 2 ATP. From there, the pyruvic acid goes through Krebs cycle and releases energy for 36 ATP. Glycolysis occurs in the cell‘s cytoplasm and Krebs cycle occurs in the mitochondria. Respiration requires glucose and oxygen and it produces carbon dioxide, water, and energy.

enzymes

C6H12O6 + 6O2 6CO2 + 6H2O + energy

PHOTOSYNTHESIS

The end result of respiration is the energy gain of 38 ATP. Remember that plant and animal cells use ATP to run the chemical reactions they need to survive.

DNA

1. DNA is the genetic material of living things. It is contained in the nucleus of most organisms. 2. DNA stands for DeoxyriboNucleic Acid. DNA contains three parts - nitrogen bases, a five

carbon sugar, and a phosphate group. Each of these bases are attached to a sugar – (deoxyribose), and a phosphate group. Each unit that includes a base, sugar, and phosphate is called a nucleotide.

3. The nitrogen bases are called adenine, guanine, thymine, and cytosine. 4. DNA is shaped in a double-helix. A double-helix looks like a spiral staircase or a twisted ladder.

The sides of the helix are the phosphate groups and sugar molecules and the rungs on the helix are the nitrogen-carrying bases.

5. The bases pair up in a specific pattern. Adenine always pairs with thymine and guanine always pairs with cytosine.

6. The pairs of nucleotides that appear on the helix can appear in any order. The sequence of the nucleotides is the code that controls the production of all the proteins of an organism. A gene is a sequence of nucleotides that controls the production of a polypeptide (large protein) or an RNA molecule. To give you an idea of size, all 46 of the human chromosomes are composed of more than 5 billion nucleotides.

RNA

1. RNA stands for RiboNucleic Acid. 2. RNA acts as a messenger between DNA and the ribosomes. If DNA is located in the nucleus

and the synthesis of proteins takes place in the ribosomes located in the cytoplasm, then there must be a way for DNA to instruct the ribosomes in protein production without leaving the nucleus. RNA is the way.

3. The sugar in RNA is ribose, not deoxyribose like DNA. 4. Also, uracil replaces thymine as a nitrogen base in RNA. 5. RNA is usually a single strand unlike DNA‘s double-helix. 6. There are three types of RNA.

1. Messenger RNA (mRNA) carries the sequence of nucleotides from the DNA in the nucleus to the ribosomes in the cytoplasm.

2. Transfer RNA (tRNA) picks up individual amino acids and brings them to the ribosome. The amino acids are then joined together in proper order to form a protein.

3. Ribosomal RNA (rRNA) is contained in the ribosome and contributes to the structure of it.

STORING AND TRANSMITTING INFORMATION

REPLICATION

Replication is the process in which DNA makes a copy of itself. Remember that each new cell gets a copy of the genetic code. DNA replicates before cell division starts. During replication several steps take place. The DNA upzips and then the bases pair up with the exposed nucleic acids. Each completed DNA molecule contains one old strand and one new strand. ATP and the action of the enzymes power the entire process.

TRANSCRIPTION

Transcription is the process whereby mRNA is copied from DNA. This process transfers the DNA code to molecules of mRNA. Several steps occur. First, the DNA unzips. One strand of DNA serves as a template for the RNA. The bases attach to the exposed nucleic acids. Once the RNA is made, it detaches from the DNA and the DNA zips back up. The code in the mRNA allows the cell to collect the right amino acids and assemble them in the correct sequence to make a particular protein. Each code is a three letter word with a base standing as a letter. Each three letter code is called a codon.

TRANSLATION

The mRNA carries the codon information to the ribosome in the cytoplasm. Translation is the process where the ribosome attaches to mRNA and carries out the formation of a protein. Several ribosomes are involved in translation thus allowing one mRNA molecule to repeatedly produce a specific protein molecule. The ribosome is made up of two parts. The smaller part attaches to the mRNA. The larger part contains a enzyme that helps to link amino acids together to form a protein. The tRNA brings specific amino acids to the ribosome to be joined to a forming protein strand. Each tRNA has an amino acid attached and an anticodon. The anticodon pairs with a codon on the mRNA and thus amino acids are added in proper sequence.

MITOSIS VERSUS MEIOSIS

MITOSIS is a type of cell division, which generates two identical cells and DNA of the mother cell. It occurs in body cells – somatic cells. Mitosis maintains the chromosome number and generates cell replacement, maintenance, and repair of the organism. Mitosis requires one DNA replication and one nuclear division. MEIOSIS is a process in which the normal number of chromosomes in a cell is reduced by half or a HAPLOID number. Chromosomes in cells occur in pairs called homologous chromosomes. Cells that have homologous chromosomes are said to have DIPLOID (2n) number of chromosomes. Sex cells or GAMETES must have a haploid number of chromosomes. When two gametes combine (sperm fertilizes egg), then the cell has a full compliment of needed chromosomes.

Meiosis requires two cell divisions one after another. The DNA only replicates once. In Meiosis I, the homologous (paired) chromosomes separate. During Meiosis II, the chromatids of each chromosome separate. Meiosis I is just like mitosis. There are several stages involved in cell division: 1. INTERPHASE – this is the time between the formation of a cell through cell division and the

beginning of the next mitosis. DNA is replicated; more organelles and other structures are made. 2. PROPHASE – this phase takes up 60% of the total time for mitosis. During this stage, the

chromosomes coil up into short rods called chromatids. The nuclear membrane breaks down and disappears. Spindle fibers appear between the centrioles and the chromosomes attach to the spindle fibers at their centromere.

3. METAPHASE – Chromosomes become arranged along the cell‘s equator or middle. Each centromere is attached to a separate spindle fiber.

4. ANAPHASE – Each chromatid separates in each pair. Spindle fibers shorten and pull the two chromatids apart. The single chromatids move to the opposite ends of the cell.

5. TELOPHASE – After the chromosomes have reached opposite ends of the cell, the spindle fibers disappear. The nuclear membrane reforms and the chromosomes uncoil. The cell membrane pinches together and a groove or furrow forms. The cell then separates into two daughter cells. This portion of cell division is called cytokinesis. In plant cells, a cell wall forms in the middle of the cell and extends outward to the cell membrane until it separates the two daughter cells.

During meiosis, the cell goes through this cycle twice. The only exception is that the DNA is not duplicated before the second cell division. The result is four cells are formed, each with half the number of chromosomes. GENETICS AND HEREDITY The study of HEREDITY is called GENETICS. Modern genetics is based on the knowledge that traits are transmitted by means of chromosomes. Offspring resemble their parents because they carry their parent‘s genetic material in units called GENES. Genes are located on the CHROMOSOME; they are the units of heredity. You have blue eyes because your parents gave it to you in their genes. Gregor Mendel is the father of genetics and he studied the inherited traits in pea plants. He knew nothing about chromosomes and yet he was able to discover the basic principles of heredity. Mendel had logical experimental methods and he had careful record keeping. From his study, we can predict the percent of characteristic traits that will be passed off to offspring. Remember that you have traits from your mom and your dad. No one person is like any other person in their genes except for identical twins, triplets, etc. Here are some things you should know:

1. For each inherited trait, an individual has two copies of the gene – one from each parent. 2. There are alternate versions of genes – for example, blue, green, and brown eyes. These

different versions are called ALLELES. If the two alleles in a person are the same it is called HOMOZYGOUS (such as TT or tt). If they are different, it is called HETEROZYGOUS (such as Tt).

3. When two alleles occur together, one of them may be completely expressed, while the other may have no observable effect on the organisms appearance. DOMINANT alleles are traits that express themselves. RECESSIVE alleles are traits that are hidden. For every pair of traits, like purple flowers and white flowers, one trait is always dominant and one is recessive.

4. The physical appearance of the trait is called the PHENOTYPE (example: brown eyes). The set of alleles and individual receives is called the GENOTYPE (example: BB).

5. The PRINCIPLE OF DOMINANCE is when one gene in a pair prevents the other gene from being expressed. A dominant gene masks another gene. A recessive gene is masked by a dominant gene. Dominant traits are given capital letter and recessive genes are given lower case letters.

B = brown b = blue BB = brown Bb = brown bb = blue 6. The PRINCIPLE OF INCOMPLETE DOMINANCE is when one gene in a pair does not

prevent the other gene from being expressed. There is an intermediate trait shown. For instance, snapdragons have red (RR) and white (rr) flowers, but with incomplete dominance, they can have pink flowers (Rr). Neither red or white is completely dominant

THE PUNNET SQUARE The Punnett Square is a grid to help scientists show all the possible gene combinations for a cross of parents. Dominant traits are symbolized by capital letters and lower case letters symbolize recessive traits. Place one parent‘s genes at the top of the square and the other parent‘s genes on the left side of the square.

GENETIC DISORDERS

Abnormal chromosomes determine some human genetic disorders. Abnormalities can occur due to NONDISJUNCTION. Nondisjunction is the failure of a chromosome pair to separate during meiosis. When nondisjunction occurs, half of the gametes produced lack one chromosome and the other half have an extra chromosome. Several serious problems result from cells with the wrong number of chromosomes (too many or too few). Down‘s syndrome can result from having three copies of chromosome 21 (instead of just two). Abnormalities and diseases can also be a result of MUTATION. The gene mutates (it has different nucleic acids) and can no longer function normally. This abnormality can be passed onto the offspring. Mutations result in diseases like sickle cell anemia, Huntington‘s disease, and cystic fibrosis. Colorblindness and hemophilia are sex-linked traits. These traits are carried on the ‗X‘ chromosome. The mother acts as a CARRIER. She carried the defective gene but does not show the disease. She

Let’s try a cross where there is complete

dominance. Seeds can have bumpy

shells or smooth shells. Bumpy is

dominant, B and smooth is recessive, b.

Show the cross of BB and Bb in the box

to the left. What are the offspring?

Now let’s try is again with incomplete

dominance. Red (RR) are crossed with

white (rr) snapdragons. Show the cross

in the box to the right. What are the

offspring?

can then pass the defective gene on to her children. If the child is a boy, then he will express the disease because he does not have another ―X‖ chromosome to mask the defect. GENETIC ENGINEERING Genetic engineering involves different approaches, but share the same four basic steps:

1. Cutting the DNA from an organism containing the gene of interest. 2. Making a combination of the original DNA fragment and DNA fragments from the organism that

is going to carry the new gene (both DNA together is called recombinant DNA). 3. Cells are treated to make many copies of the recombinant DNA. 4. Cells are then screened to remove the cells that did not take up the recombinant DNA.

This technique has been used to produce insulin and other needed drugs. Bacteria are given the gene for the protein insulin and then the bacteria produce it. In addition, vaccines for diseases can be produced. The genes for the disease-causing virus‘ surface proteins can be inserted into a harmless virus and then put into a vaccine. DNA technology has been used to develop new strains of plants, which in turn can be used to increase food crop yields. For example, by transferring genes for enzymes that are harmful to hornworms into tomato plants, scientists can make tomato plants toxic to hornworms, and thus protect these plants from these pests, which otherwise would seriously damage them

KINGDOMS OF ORGANISMS

Taxonomy Scientists these days study chromosome structure, reproductive potential, biochemical similarities, and embryology to determine the relationships among organisms. Organisms are then given classification names. The classification levels are:

Kingdom-Phylum-Class-Order-Family-Genus-Species (to remember order, say: King Philip Came Over For Great Spaghetti)

For instance, here is the classification for a tiger: Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Carnivora, Family Felidae, Genus Panthera, Species tigris. The scientific name for tiger is Panthera tigris.

Currently there are five kingdoms, but some scientists talk about six kingdoms. Six

kingdoms will be discussed here, although you should also know the five. In the five kingdom arrangement, there is a kingdom Monera. In the six kingdom arrangement every kingdom is the same except Kingdom Monera is replaced by Kingdom Eubacteria and Kingdom Archaebacteria.

KEY CHARACTERISTICS OF THE KINGDOMS

CHARACTERISTICS EUBACTERIA ARCHAE-

BACTERIA

PROTISTA FUNGI PLANTAE ANIMALIA

CELL TYPE Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote

CELL STRUCTURE Cell wall, with

peptidoglycan

Cell wall, no

peptiodoglycan

Mixed Cell wall,

chitin

Cell wall No cell wall

BODY TYPE Unicellular Unicellular Unicellular, multicellular

Unicellular, multicellular

Multicellular Multicellular, with organs

NUTRITION Autotrophic

and heterotrophic

Autotrophic

and heterotrophic

Autotrophic

and heterotrophic

Heterotrophic Autotrophic Heterotrophic

EXAMPLE Bacillus subtilis

Methano-microbium mobile

Euglena gracilis

Pennicillium notatum

Pinus radiata (pine tree)

Loxodonta Africana (elephant)

The key characteristics listed above are explained below:

1. Cell Type: Organisms are either prokaryote or eukaryote. Two of the kingdoms are prokaryotic and the other four include eukaryotes.

2. Cell construction: Cells are built differently. Some cells have cell walls made of different compounds, and some cells have no cell walls at all.

3. Body Type: Organisms can be unicellular or multicellular and may have tissue or organs. Only one kingdom includes organisms that have organs; organisms in the other kingdoms vary in body type.

4. Nutrition: Organisms obtain their nutrition through photosynthesis or by heterotrophic means. Some kingdoms have organisms that use both methods; but organisms in other kingdoms use strictly one method.

EUBACTERIA Characteristics: prokaryote, microscopic, lives as a single cell or in colonies in water. Most are

autotrophic (producers), a few are heterotrophic (consumers); have the same kind of lipid (peptidoglycan) in their cell walls; found in practically every environment on earth.

Structures: flagella, capsules Growth: cell membrane and availability of food set growth limit; keep moist and warm for

optimal conditions Reproduction: binary fission (splits in two) Beneficial: decomposers of matter, in digestive system, nitrogen-fixers Harmful: can cause diseases like strep throat, pneumonia Examples: Bacteria, blue-green bacteria

ARCHAEBACTERIA Characteristics: prokaryote, microscopic, lives as a single cell or in colonies in water. Most are

autotrophic (producers), a few are heterotrophic (consumers); do not have peptidoglycan in their cell walls; found in extreme environments on earth – swamps, hydrothermal vents, very salty places. Also found in soil and seawater. Most receive their energy from inorganic sources.

Structures: flagella, capsules Growth: cell membrane and availability of food set growth limit; methane (methanogens) and

sulfur (thermophiles) are two types of nutrients used for energy. Reproduction: binary fission (splits in two) Beneficial: unknown Harmful: unknown Examples: Methanogens, Thermophiles, Halophiles PROTISTA Characteristics: Most diverse kingdom; Animal-like organism, distinguished by method of locomotion,

eukaryotes, mainly microscopic, single celled or multicellular; some are autotrophic (algae) and many are heterotrophic (protozoans); All single celled eukaryotes are protists except yeast.

Structures: flagella, pseudopodia, capsules, cell organelles, membrane bound, some are photosynthetic

Growth: cell membrane, availability of food set growth limit. Reproduction: asexual or sexual Beneficial: some are harmless Harmful: sleeping sickness, malaria Examples: Most unicellular organisms - protozoa, amoeba, zooplankton, euglena, paramecium,

and algae FUNGI Characteristics: Animal-like organism, cannot move, eukaryotes, mainly multicellular, parasitic,

symbiotic, heterotrophic, Structures: root-like, caps, filaments called hyphae Growth: based on food source and availability; obtain nutrients by secreting digestive

enzymes into their environment and the absorbing the digested organic molecules. Reproduction: asexual, sexual Beneficial: yeast, penicillin, decompose organic material Harmful: cereal rusts, ringworm, athlete‘s foot, Examples: mushrooms, bread molds, slime molds, rusts and smuts, yeast PLANTAE Characteristics: eukaryotes, mainly multicellular, can‘t move, autotrophic Structures: cellulose cell walls Functions: based on cell and tissue chemistry

Systems: all present and functioning Growth: determined by available nutrients Reproduction: asexual, sexual by spores, seeds, flowers, and cones Examples: All multicellular plants - Mosses, ferns, gymnosperms (pine cone plants),

angiosperms (flower-bearing plants) ANIMALS Characteristics: eukaryotes, multicellular, heterotrophic, most are motile at some point in their

lifetime Structures: all present and unique to the organism Functions: based on nutrition, cell and tissue chemistry, and individual demands Systems: all present and functioning Growth: based on hormone action and nutrition Reproduction: asexual, sexual Examples: All multicellular animals - Invertebrates (sponges, jellyfish, coral, sea anemones,

planarian, fluke, tapeworm, hookworm, earthworm, mollusks, starfish, insects, crustacean); vertebrates (fish – cartilaginous and bony); amphibians – frogs, salamanders; reptiles – snakes, lizards, turtles; birds; and mammals

MORE ON PLANTS

One of the major ways that land plants differ is the way they transport water and nutrients throughout the plant body. The majority of land plants have an internal system of connected tubes and vessels called vascular tissues. These plants, called vascular plants, are the plants that you are the most familiar with –maple trees, grasses, roses, and house plants. Vascular plants have roots, stems, and leaves. The other group of plants lack vascular tissue. They transport water and nutrients by osmosis and diffusion.

VASCULAR PLANTS AND THEIR TISSUES

Plants with vascular tissue have true roots, stems, and leaves. They have an internal network of tubes that carry water, nutrients and glucose made from photosynthesis throughout the plant. The ROOTS absorb water and nutrients from the soil and they anchor the plant. The roots also store food that was made in the leaves. The STEM contains vascular tissue that transports substances between the roots and the leaves. The stem also supports plant growth above the ground. It is the backbone of the plant. There are two types of vascular tissue: xylem and phloem. XYLEM transports water and minerals absorbed by the roots up to those parts of the plant that are above the ground. The PLOEM carries sugar and other soluble organic materials produced by photosynthesis from the leaves to the rest of the plant. The LEAVES use sunlight, water, and carbon dioxide to carry out photosynthesis. They also transport the food they produce to the rest of the plant in a process called translocation. In addition leaves

exchange gases and water vapor with the atmosphere. The outside of the leaf is covered with a waxy layer that slows the evaporation of water from the leaf. The leaf has openings called stomata. Each STOMATE controls the exit and entry of water and gases. Most stomata are located on the underside of the leaf where the surface is shaded. Ninety percent of the water that enters the roots is lost through the leaves in a process called transpiration. The middle portion of the leaf contains the chlorophyll and other pigments. The vascular plants can be divided into those that have seeds and those that have spores. Ferns, horsetails, whisk ferns, and club mosses all have spores. All other plants have seed – either in a cone or in a fruit. DIFFERENT GROUPS OF PLANTS Ferns are seedless plants that contain vascular tissue. Fern fronds spread out over a large area and so ferns are able to survive in dim sunlight. Gymnosperms produce their seeds in cones and generally keep their leaves throughout the year (evergreen). Conifers means ―cone-bearer‖. Pines, spruce, fir, and other conifers are characterized by their stiff cones and needle-like leaves. Conifers can thrive in harsh conditions because they have special adaptations. Their needles are covered in a hard waxy outer coating and have little exposed surface area. This means that they do not lose much water. They shed their needles throughout the year instead of once a year. They send their roots out into a wide area of soil instead of deep into the soil. This allows them to survive in areas where the soil is not very deep. Angiosperms are flowering plants. They produce seeds enclosed in fruits. (Gymnosperm seeds are uncovered in their cones.) Angiosperms are deciduous plants. That means that they lose their leaves every fall. During pollination, pollen grains stick to the top of the stigma. From there, the pollen grain grows a pollen tube down through the style to the ovary where it fertilizes the egg. Animals, wind, and water all transport pollen from flower to flower. The nonessential flower parts are modified to aid the specific type of pollination a plant undergoes. In flowers that are pollinated by animals, the stem and receptacle hold the flower out where its colors and scent are most obvious. Some flowers produce nectar, a sweet liquid. Fruits are formed when the egg is fertilized and the ovary begins to swell and ripen. It changes color and becomes fleshy or dry. Animals eat the fruit and pass the seed out to new places through their waste.

SEXUAL REPRODUCTION IN FLOWERS In plants that produce them, the flower functions in sexual reproduction. The parts are as follows:

1. Stamen: male part of flower. Many flowers have 3-5 stamens.

2. Filament: the thin stem-like portion of a stamen.

3. Anther: pollen is produced at the tip of the filament.

4. Pistil (labeled carpel in drawing): the female part of the flower. Most flowers have a single pistil. The pistil contains three parts.

5. Ovary: The swollen base of the pistil. Within the ovary, one or more ovules produce the egg cells.

6. Style: The slender middle part of the pistil.

7. Stigma: At the tip of the style. The stigma produces a sticky substance to which pollen grains become attached.

SEEDS Seeds gave the animal world a new high-energy food source. They provide food for mammals that need lots of energy to help maintain their body temperature. People have depended upon angiosperms for food, lumber, fibers, clothing, and medicines. The development of plants that have seeds really helped plants to survive in a variety of places. Seeds can lie dormant (asleep) if the conditions aren‘t right for growing. Some seeds, because they have burrs or stickers, can travel a long way on animals or in the wind before falling to the ground and sprouting. This spreading of seeds, called dispersal, is good for plants. It helps to spread the plant‘s genes over a wider area.

INVERTEBRATES The major difference between animals and plants is that animals can move. Animals cannot produce

their own food so they must move to find it. The arrangement of body parts is related to how a particular animal meets the challenges of living, which includes gathering food, protecting itself, and reproducing. Differences in body structure are useful in classifying animals. Invertebrates make up 97% of the animal kingdom. There are 15 invertebrate phyla and some of them will be discussed below. PHYLUM PORIFERA Sponges have the simplest body organization of any phlya. They have no head, mouth, or any organized systems like digestion and circulation. The cells are not organized into tissues and organs. They live in shallow seas. They are all shapes and sizes, as well as colors.

They do not move around, attaching themselves to a rock, shell, or other substance. They feed by filtering food and nutrients out of the water. Their bodies consist of two layers of cells with a jelly-like layer in between. PHYLUM COELENTERATA Coelenterates are bag-like animals with long flexible tentacles. Most live in seawater, but hydras live in freshwater. Coelenterates include jellyfish, sea anemones, and corals. Coelenterates have a digestive gut with only one opening. They have radial symmetry (Symmetry where body parts are arranged around a central point - like a wheel.) Their bodies consist of two layers of cells, separated by a jelly-like substance. They also have special stinging cells called cnidocytes.

PHYLUM PLATYHELMINTHES This is the group of flatworms which includes the flatworm, the fluke, and the tapeworm. They have a digestive cavity with only one opening. They have no circulatory or respiratory system. Flukes are parasites and pose a serious health problem. Many can cause serious and even fatal diseases. They live off the fluid of their host (blood or mucus). Most flukes are endoparasites which means they live inside the body of their hosts. Their life cycle generally involves two or more hosts. For instance, the oriental lung fluke infects crabs which are eaten raw by humans who then get infected with the worms. To not get infected, humans could cook the crab meat! Tapeworms live in the intestines of vertebrates where they feed by absorbing food that has already been digested by their host. PHYLUM NEMATODA

This phylum includes roundworms, also called nematodes. Different types include Ascaris (intestinal roundworm), hookworms, trichina, and pinworm. They have tubular bodies and have a digestive tract open at both ends. Most roundworms are parasites. They feed on plants by sucking the juices from them. They can infect humans, usually from poor sanitation and cause diseases. These roundworms are pinworms, hookworms, or intestinal roundworms. Trichina infects pigs and can cause trichinosis in humans who eat raw or undercooked pork. PHYLUM ANNELIDA

This phylum is the segmented worms - they have bodies that are divided into a series of segments which often look like visible rings on the outside of the body. They are also called annelids. They include earthworms, leeches, and a variety of marine worms. They have three tissue layers and a body that has bilateral symmetry (symmetry where body parts are identical on both sides – like humans). Annelids have a true coelom (internal organs are suspended by double layers of a membrane). Annelids also have a more complex circulatory, nervous, and respiratory systems than other worms.

PHYLUM MOLLUSCA This phylum is the soft bodied mollusks. They live in fresh as well as seawater. They come in a variety of sizes. Many are protected by one or more shells. They are classified according to what kind of shell that they have. They include the two-shelled mollusks (clams, scallops, oysters), one-shelled mollusks (snails) and no-shelled mollusks (squid, octopuses, cuttlefish). Mollusks have bilateral symmetry and they have a true coelom. They have three distinct body parts - head-foot, visceral mass, and mantle. Clams obtain both food and oxygen from the water that flows through their bodies. They

are filter feeders. They have gills that absorb the oxygen from the water. They have an open circulatory system and a three chambered heart.

PHYLUM ECHINODERMATA

Echinoderms are spiny-skinned and include starfish, sand dollars, brittle stars, and sea urchins. They live only in ocean/marine habitats. Echinoderms have an endoskeleton that is covered by a thin skin. They are considered the most advanced form of invertebrates and are classified closest to vertebrates due to a larva stage that is bilaterally symmetrical. They are radially symmetrical as adults. They have no brain. They breathe through skin gills that are protected by the spines. The starfish has a remarkable ability to regenerate body parts. So if a starfish loses an arm, it will regrow.

PHYLUM ARTHROPODA The Arthropod phylum has more species than any other. Three quarters of all species on earth are insects. Their great success is due in part to their body structure. They are characterized by having jointed appendages, a segmented body, and an outer skeleton (exoskeleton). It is made of chitin. They have a well developed open circulatory system with a long dorsal tube for a heart. The nervous system consist of two long ventral chains of nerves and a simple brain. The five major classes of Arthropods are insects (bees, beetles, mosquitos), arachnids (spiders, scorpions, ticks, mites), crustacean (crayfish, lobsters, crabs, shrimp), Diplopoda (millipedes), and Chilopoda (centipedes). Insects are the only arthropods that can fly. They are both beneficial (pollination) and harmful (crop destroyers). They have three distinct body parts and three pairs of legs. They include grasshoppers, crickets, termites, aphids, flies, mosquitoes, butterflies, moths, beetles, ants, wasps, and bees. VERTEBRATES PHYLUM CHORDATA This phylum is the most complex of all animals. The vertebrates (animals with backbones) make up the largest subphylum in the phylum Chordata. At some point in their development, all chordates possess four distinctive structures: a notochord, a nerve chord, gill slits, and a tail. SUBPHYLUM VERTEBRATA Vertebrates have a strong flexible backbone. Three classes live entirely in water - jawless fish, cartilaginous fish, and bony fish. Amphibians are adapted to life on land as well as the water. Reptiles and mammals are primarily land animals. All but a few birds can fly. Vertebrates have a number of characteristics in common. They have bilateral symmetry. The major sense organs are located in the head. All vertebrates have a closed circulatory system and a coelom (large central body cavity that contains the important organs). They all have an endoskeleton which supports and protects them. The endoskeleton can be made of cartilage or bone. A distinctive feature of the skeleton is the backbone - vertebral column. They have pairs of muscles that work in opposite directions to push and pull the bones.

Their bodies are covered with scales, skin, feathers, or hair. They have a digestive tube that goes from mouth to anus. They have gills or lungs for breathing and have a closed circulatory system with two-, three-, or four-chambered hearts. They have arteries to take the blood from the heart and veins to take it back to the heart. Their excretory (waste) system consist of kidneys, and associated tubes. Their nervous system includes a spinal cord, brain, nerves, and sense organs. There are male and female sexes. CLASS AGNATHA They do not have jaws but use a sucker-like mouth to latch onto their prey. They have smooth, cylinder-like bodies with flexible skeletons of cartilage. They are ectothermic (cold-blooded). The only two surviving members of this class are the hagfishes and lampreys. CLASS CHONDRICHTHYES These are the cartilaginous fishes. Their skeletons are made of cartilage. They have hinged jaws lined with rows of teeth. They are ectothermic. The class includes sharks, rays, and skates. CLASS OSTEICHTHYES Most of the world‘s fishes are in this class. They have skeletons made of bone, and have jaws and scaly skin. They get their oxygen from the water through gills. They are ectothermic. CLASS AMPHIBIA Amphibians live on land and in the water. They have internal lungs that are not very efficient and they also get oxygen through their moist skin. They keep their skin moist with a mucus and they can never venture too far from water. They return to the water to lay their eggs and their young pass through a larval stage in the water before beginning their life on land. They are ectothermic. Amphibians include frogs, toads, and salamanders. In frogs, the young are called tadpoles and live in the water. The tadpole goes through metamorphosis, or change, as it develops into an adult. A tadpole begins life with a short tail and breathes through gills. Gradually it develops arms and legs and its tail begins to disappear. The lungs replace the gills and the frog leaves the water. CLASS REPTILIA Reptiles were the first animals that were truly independent of the water. They do not need to keep their body moist for their skin is thick and covered with scales. They do not need to return to water to have babies for their young are laid in eggs. These eggs hold food for the embryo to live off of while it is growing. They are ectothermic. Reptiles include the extinct dinosaurs, turtles, tortoises, alligators, crocodiles, lizards, and snakes. CLASS AVES This is the class of all birds. Birds arose from reptiles and they grew feathers instead of scales to insulate themselves. The feathers distinguish birds from other classes of vertebrates. Birds are endothermic (warm-blooded) which means their body temperature remains constant.

CLASS MAMMALIA Mammals have several characteristics not found in other vertebrates. They nurse their young using milk from mammary glands. Mammals have live births - the young are born live after spending time developing in their mother‘s body. They have body hair that acts as insulation and also protects the body from injury. Mammals have a large well-developed brain and they are the only animals that have an external outer ear for hearing. Their body is divided into two parts - the chest and the abdomen. The diaphragm separates the two parts. They are endothermic. Mammals include monotremes (duck-billed platypus, spiny anteater). They have mammary glands which make them mammals, but they lay eggs. Mammals also include marsupials (kangaroos, koalas, opossums). They bear live young, but the young are not as developed as other mammals. These babies complete their development inside a pouch attached to the mother. Placental mammals include 95% of all mammals. The embryo of a placental mammal is implanted in the mother‘s uterus - the mother‘s reproductive organ. The placenta forms, connecting the young mammal directly to the mother providing nutrients and oxygen.

ECOLOGY Science Review

When studying for this portion of the test, be sure to review the following:

1. Analyze dependence of organisms on each other and the flow of energy and matter in an ecosystem. A. Evaluate relationships between organisms, populations, communities, ecosystems, and

biomes. B. Describe the flow of matter and energy through an ecosystem by organizing the

components of food chains and webs. Assessment will focus on the following:

1. Understanding the identifying characteristics of major biomes of the world on a conceptual level, rather than identifying them on maps.

2. Describing predator-prey, producer-consumer, parasite-host, scavenging, or decomposing relationships among organisms.

3. Understanding and analyzing the physical conditions (food, space, water, air, and shelter) necessary for organisms to survive in an environment.

4. Understanding that the amount of matter remains constant as it flows through an ecosystem. 5. Explaining the flow of energy through an ecosystem and that energy may change from one

form to another. 6. Using diagrams to interpret the interactions of organisms within food chains and webs. 7. Determining the role of different organisms in food chains and webs.

Become Familiar with the following terms:

Heterotroph

Autotroph Adaptation Habitat Niche Food Chain Food Web Predator Prey Parasite

Decomposer Host Producer Consumer Population Community Ecosystem Symbiosis Parasitism Herbivore Carnivore

Omnivore Biome Tundra Taiga Temperate Deciduous forest Desert Grassland Tropical rain forest Arid

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ECOLOGY

ECOSYSTEMS Life on earth extends from the ocean depths to a few kilometers above the earth‘s surface. The area where life exists is called the biosphere. The biosphere can be more easily understood by breaking it into smaller components called ecosystems. An ECOSYSTEM is a physically distinct, self-supporting unit of interacting organisms and their surrounding environment. It is made up of biotic and abiotic interactions. The BIOTIC factors of an ecosystem are the living organisms in the area. The ABIOTIC factors are the non-living, or physical, components of the area like light, soil, water, temperature, wind, and nutrients. The essential factors that make an ecosystem successful are a source of energy, a storage of water, and the ability to recycle water, oxygen, carbon, and nitrogen. Ecosystems must maintain an ecological balance. This can be helpful or harmful to the members that make up the community depending upon whether they are predators or prey. A PREDATOR is an animal that feeds on other living things. The animal it feeds upon is the PREY. Lions (predator) hunt down and kill antelope (prey). Recently several state parks have allowed hunting for deer. The deer no longer have a predator to keep their numbers down and so the parks are using man to do that. When there are too many deer, too much of the forest and undergrowth are eaten and there is not enough food for all deer to live a healthy life. Each of the biotic organisms in an ecosystem interrelate with the others. A SYMBIOTIC relationship between two members of a community is one in which one or both parties benefit. PARASITISM is a relationship that involves a HOST organism which is harmed by the presence of the other organism (fleas on dogs and cats). A parasite/host relationship is usually associated with diseases. HIV is a virus that is a parasite living in the human body. A successful parasite learns to live in its host, harming it but not killing it. Natural resources are necessary for human survival and the making of necessary products. The natural resources are water, air, soil, wildlife, and forests. Problems that are now being faced are related to erosion, soil depletion, species extinction, deforestation, desertification, and water shortages. Efforts to reverse these problems and their environmental damages are found in the planned programs of reforestation, captive breeding, and planned farming through efficient plowing and planting procedures. Disruptive changes can easily upset the stability of an ecosystem. Destructive acts of nature can occur. A forest fire can destroy all plant and animal life in a forest, along a river, and around the shore of a pond. It can also pollute a pond with ash. Humans are unique in our ability to modify our ecosystem. Pollution from human acts can also affect an ecosystem. A chemical spill or pesticides sprayed overhead can kill all plant and animal life with which it comes in contact with. A housing development along the bank of a river or on the shore of a pond can bring both garbage and noise pollution, in addition to direct physical destruction of these habitats.

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COMMUNITIES An ecosystem‘s biotic factors interact with each other and compose a COMMUNITY of living things that coexist. Each community is composed of populations. A POPULATION is a group of small individuals of a single species that occupy a common area and share common resources. The number of populations within a community varies. A tropical rain forest community may have thousands of populations while a desert community may have very few. Just like communities are made up of populations, each population is composed of interacting individuals. Each individual organism lives in a specific environment and pursues a particular way of life. The surroundings in which a particular species can be found is called its habitat. An organism can inhabit an entire ecosystem like a woodpecker might occupy the whole oak forest. But the spider may only inhabit the trunk of one of the oak trees. The way of life that a species pursues within its habitat is called its ecological niche. An organism‘s niche is composed of biotic and abiotic factors. Some niches can be very broad (rats) while others can be very limited (panda).

POPULATIONS IN ECOSYSTEMS The population of an area is affected by the new offspring produced in the area. New plants and animals moving in from other places increase the size of the population. The death of organisms and animals moving out of the area decrease the size of the population. There is a direct relationship between the number of plants and animals in an area which is in ecological balance. If the number of one of them is increased or decreased, it will affect the numbers of the other. During deer season, the number of deer is reduced by man. The plants that the deer eats will increase during this season. A change in population may be helpful or harmful to the community. If insects are killed by insecticide, the animals that depend on them for food must move elsewhere. Even the human population changes as the seasons change. In the summertime, the coastal area is more widely populated by vacationing people. In the wintertime, the snowy, mountainous areas are more populated by snow skiers.

THE FLOW OF MATERIALS

Each ecosystem has its producers, consumers, and decomposers. Plants are called PRODUCERS because they are able to use light energy from the sun to produce food (sugar) from carbon dioxide and water. Animals cannot make their own food so they must eat plants and/or other animals. They are called CONSUMERS and there are several types. HERBIVORES are animals that eat only plants. CARNIVORES are animals that each only other animals. OMNIVORES are animals that eat both plants and animals. DECOMPOSERS (bacteria and fungi) feed on decaying matter. Decomposers speed up the decaying process that releases mineral salts back into the food chain for absorption by plants as nutrients.

All living things need energy to grow, energy to reproduce, energy to survive. All ecosystems, therefore, need energy. Their energy begins with the sun. Plants trap the solar energy and, through photosynthesis, convert it into the sugars that are their food. Animals eat the plants, taking some of that sun-harvested energy into themselves. Other animals eat those animals.

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Eventually, the animals die. Their bodies are cleaned off by SCAVENGERS and dismantled by decomposers. A SAPROPHYTE is an organism that feeds on dead organisms (a DECOMPOSER). For example, fungi use the nutrients in dead leaves and other items on the forest floor for food. The remaining minerals are returned to the soil, which is enriched by them so that it is once again fertile and can support new plants. Around and around it goes. These relationships—which organisms eat which other organisms, and how the energy is passed from one to another—can be thought of in terms of an imaginary chain. In this chain, each organism forms a single link: the chain stretches from the blackberries to the mouse that eats one to the owl that catches the mouse. Such an imaginary chain is known as a food chain. FOOD CHAINS describe the flow of energy, in the form of food, from one organism to another. Each organism forms a link in the chain. Almost all food chains begin with producers harvesting energy from the sun. From there the energy is passed from producers to consumers: herbivores, carnivores, and omnivores. When these die the energy passes to scavengers and decomposers, and back into the soil. Decomposers, as the last step to replenishing the soil, are both the end and the beginning of any food chain. We can see that, as with a real chain, removing any link causes the entire chain to collapse. If the plants were removed, for example, it would not simply affect herbivores—for carnivores eat the herbivores. If the decomposers were removed, the soil would not become replenished with minerals; new plants would not grow; herbivores would not feed on them. And if the sun were removed from the chain—perhaps by pollution blocking its light—nothing else on the chain would remain. The last living recipient of energy in a food chain is called the ―top consumer.‖ It will not be consumed itself until it dies. Food chains are a helpful way to think about how energy moves through an ecosystem. In any real situation, though, there are many different food chains, all connected to each other. A food web is a diagram that combines food chains to show these connections. Food webs are made of interconnected food chains. These relationships can also be imagined as a pyramid, with plants on the bottom, then herbivores, and then carnivores. This kind of diagram is known as an energy pyramid. Energy is lost between every feeding level of an energy pyramid. Only about one-tenth of the energy in plants flows to herbivores. One tenth of the energy in herbivores flows to carnivores. The rest is used up in the process of staying alive or lost as heat. The most abundant organisms in any ecosystem, aside from decomposers, will be the producers. Plants have the most energy available to them because they trap it directly from the sun. There will be fewer carnivores and will be even fewer top carnivores. Small populations of top carnivores depend on much larger populations of other animals to survive

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All organisms need certain chemicals in order to live. The most important ones are water, oxygen, carbon, and nitrogen. The continuous movement of chemicals throughout an ecosystem is called recycling. The amount of water or carbon in an ecosystem does not change, but the form of the water or carbon may change. The water may be locked in ice or in a rain cloud and not in a lake or in the ground. BIOMES Communities are members of a larger ecological unit called a biome. A biome is an extensive area of similar climate and vegetation. A biome‘s abiotic (non-living) factors determine what plants and animals live there. The major influences are temperature, light intensity, and patterns of rainfall which determine the availability of water. There are six basic biomes on earth: tundra, taiga, grassland, deciduous forest, desert, and tropical rain forest. You need to be able to understand these biomes and not just locate them on a map. Biomes that are closest to the poles experience the coldest weather conditions for they are furthest away from the sun due to the tilting of the earth. Biome Characteristics Temperature Rainfall Location TUNDRA the coldest biome very cold (32°F) light rainfall high altitudes, high

latitudes TAIGA the biome that sustains cold (50°F) medium rainfall occurs in northern

Evergreen trees, but is climates or high up Pretty cold mountains

DECIDUOUS Forest where trees lose more temperate (75°F) medium rainfall located in middle FOREST their leaves; latitudes

GRASSLAND grasses and shrubs, more temperate (68°F) low rainfall middle of continents,

Few trees away from large water sources

FOOD WEB

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DESERT very little vegetation hot during the day very little rainfall near the

equator (86°F) colder at night or near mountain

ranges

RAIN FOREST lots of plants and temperate (77°F) heavy rainfall usually occurs near the

Trees; very diverse equator

CHARACTERISTICS OF SCIENCE Become familiar with the following terms: Research problem Hypothesis Dependent variable Independent variable Variable Experimental group

Control group Conclusion Accuracy Prediction Hypothesis Data

THE SCIENTIFIC METHOD Science is NOT just a body of knowledge; it is also something that people do to find out about the world around them. Science involves observing the world and its events. Scientists seek facts – try to solve deeper mysteries Scientific Method: Science is investigated by a logical process, sometimes called the scientific method. This requires searching for an answer in an orderly, systematic manner. There is not one order for the six steps, but it should be done logically.

1. State the Problem

Being curious; having questions about what you observe 2. Analyze the Problem (research the problem)

Gathering information; look for patterns; look at what other research has done

3. Form a hypothesis Hypothesis: educated guess on what you think will happen

4. Test the hypothesis through experimentation Experimentation; make sure you have a control and a variable; test

multiple times. 5. Record and analyze data Look at your data; look for patterns 6. Form a conclusion

Was your hypothesis true?; no theory can become fact until it has been tested under all possible conditions; Your hypothesis is not always true.

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Sometimes, you can make a prediction about what will happen. This is an educated guess based on past experience. You can also make an inference. An inference is an implied answer based on indirect observations. For instance, you might record that it rained today if you went outside after school and saw puddles on the sidewalk, but you never actually saw it rain. The Research Problem Once the problem has been stated, the problem must be investigated. This is done through research. The scientist searches the literature published on the problem, interviews potential experts, and searches the Internet to find all the information available. The problem must be restated so that only one variable is tested. Variables are the specific factors that can be measured. The independent variable (manipulated variable) is a set of conditions that will be changed by the researcher. The dependent variable (responding variable) is the set of conditions that may or may not change as the independent variable is changed. The dependent variable is the variable being tested. The group of samples or subjects that is tested by changing a variable is the experimental group. Another set of samples or subjects makes up the control group. This group is EXACTLY like the experimental group, except that no variable has been changed. The purpose of the control group is to verify whether or not changes occurred in the experimental group and whether or not the changes were a result of the independent variable. The anticipated results are stated at the beginning of the experiment in the form of the hypothesis. Sample Research Problem 1 A student wishes to test the rate of photosynthesis in plants at different temperatures. Elodea plants will be tested at different temperatures and the rate of oxygen (O2) production will be measured. Research Problem: Does temperature affect the rate of oxygen production in Elodea?

Independent Variable: ___________________________________

Dependent Variable: ___________________________________

Experimental group: Set of plants ___________________________________

Control group: Set of plants ___________________________________

Hypothesis: Increase in temperature will increase the rate of O2 production

Sample Research Problem 2 A student wishes to find out if eating breakfast has any effect on reaction time. Research Problem: Does eating breakfast affect reaction time of high school students?

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Independent Variable: ____________________________

Dependent Variable: ____________________________

Experimental group: Students who ______________________________________

Control group: Students who ______________________________________

Hypothesis: Students who ______________________________________

Practice Section - Read the following and answer the questions that follow. A. Mrs. Brim wants to find out why seawater freezes at a lower temperature than fresh water. B. Mrs. Brim goes to the media center and reads a number of articles about the physical properties of

solutions. She also reads about the composition of seawater. C. She also travels to a nearby beach and observes the conditions there. D. After considering all this information, Mrs. Brim sits at a desk and writes, My guess is that sea

water freezes at a lower temperature than fresh water because sea water has salt in it. E. She goes to her classroom lab and does the following: 1. Fills each of two beakers with 1 liter of fresh water. 2. Dissolves 35 grams of table salt into one of the beakers. 3. Places both beakers in a refrigerator whose temperature is -1°C. 4. Leave the beakers in the refrigerator for 24 hours. F. After 24 hours, Mrs. Brim takes the beakers out of the refrigerator and looks at them. She finds

that the fresh water beaker is frozen and the salt water is still liquid. G. She writes in her notebook, It appears as if the salt water freezes at a lower temperature than

fresh water does. H. She continues, ―Therefore, the reason seawater freezes at a lower temperature is that sea water

contains dissolved salts while fresh water does not. Which statement contains the CONCLUSION? _________ Which statement refers to GATHERING INFORMATION? ___________ Which statement contains the HYPOTHESIS? ___________ Which statement contains the TEST OF THE HYPOTHESIS? ___________ In which statement is the PROBLEM defined? ___________ Which statement contains the DATA in the experiment? ___________

EXPERIMENTAL ERROR

Sometimes, it is helpful to determine if there is error associated with your experiment. Sources of error can come from not doing the lab well (poor laboratory technique), improper experimental set-up, and errors in data collection. You may be asked to determine sources of error on the graduation test. Think of any way that the experiment could have been done wrong and this will lead to a source of error.

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ANALYZING, EVALUATING, AND

PRESENTING INFORMATION During the experiment, data and observations are recorded in a logbook. This data then is analyzed in a variety of ways: data tables, graphs, etc. You must be able to read a data table or graph and determine what it is trying to say. The analysis of the data is summarized in a conclusion. The conclusion will state whether the hypothesis was supported or rejected. The experiment should be repeated multiple times to verify the accuracy of the data before stating the conclusion.

SAFETY EQUIPMENT AND RULES Be familiar with the following safety rules for working in a laboratory: 1. Always wear goggles when working with flames or chemicals. This includes acids. 2. Never smell a chemical directly under your nose. Wave the odor from the bottle or beaker towards

your nose (called ―wafting‖). Remember that leaving a cap off of a smelly chemical can cause the chemical‘s smell to spread throughout the room in a process called diffusion.

3. Be sure to use tongs to handle hot equipment. Use the back of your hand held close to the item to determine if it is too hot.

4. When heating chemicals, make sure to point to opening of the test tube away from you and your partner.

5. When lighting a Bunsen burner, light the match and then turn on the gas. 6. Know the location of the fire extinguisher, eyewash, first aid kit, and emergency shower. 7. Be sure to read all directions before starting an experiment. 8. Report all spills and accidents to your teacher immediately. Safety goggles should be worn at all times in the lab. It is the single most important safety device. The fire extinguisher should be an ABC or BC type fire extinguisher.

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PRESENTING DATA The following are examples of ways to present data. Look at the following and answer the questions that follow. Bar Graph - shows how subjects compare in relation to the main topic.

1. What information is given in this graph?

2. What week shows the highest growth rate?

3. What is the maximum height of the plant?

Line Graph - is effective in showing trends, changes over time

4. How tall was the plant the second week?

5. What period of time shows the greatest growth?

6. If the growth continues at this rate, can you estimate the height of the plant in the 7th week?

Circle Graph - shows how parts relate to a whole (percentages)

7. What is the total percent of a circle graph?

8. Why would a circle graph not measure the growth of a plant?

9. If you have 500mL of atmosphere, how many mL of nitrogen and oxygen are there?

1 2 3 4 5 6

Weeks plant has been growing

60cm

50cm

40cm

30cm

20cm

10cm

Growth of Pea Plants

Plant Height over 6 weeks

30cm

25cm

20cm

15cm

10cm

5cm

1 2 3 4 5 6

Weeks plant has been growing

Nitrogen

and

Oxygen

78%

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PROCESS SKILL PRACTICE Analyzing an Experiment

Do Plants like Coca Cola? Hypothesis: If ten plants are given Coca Cola and ten plants are given water, the plants fed Coca Cola

will be taller and have more leaves.

1. Independent variable: __________________________________ 2. Dependent Variable: __________________________________

Experimental Set-up

Water Coca Cola X X X X X X X X X X

X X X X X X X X X X

X = individual plant

3. Which group is the control? 4. Why have a control group? Name at least three factors that will be the same for both sets of plants.

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Analyzing a Line Graph Look at the graph and answer the questions below.

Beaker of Water Placed in the Freezer

-30

-20

-10

0

10

20

30

40

50

60

70

0 20 40 60 80 100

Time in Minutes

Te

mp

era

ture

in

Ce

lsiu

s

1. About what temperature is the water after 20 minutes has passed?

a. 50 C b. 43 C c. 35 C d. 24 C e. 15 C

2. How long does it take for the beaker of water to reach a temperature of 0 C

a. 10 minutes c. 40 minutes e. 70 minutes b. 30 minutes d. 50 minutes

3. After the beaker has been in the freezer for 70 minutes, its contents would most probably be

all water at a temperature slightly above 0 C

a. all water at a temperature slightly below C.

b. partly water and partly ice, all at a temperature of 0 C.

c. all ice at a temperature of 0 C.

d. all ice at a temperature slightly above 0 C.

4. What happens to the temperature from 50-70 minutes?

a. The temperature increases b. The temperature decreases c. The temperature does not change d. This information cannot be determined from this graph.

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Interpreting a Data Table

DATA ON THE PLANETS Temperature K Surface Radius Density Planet Night Day Pressure (atm) Earth radii Earth Density

Mercury 13 683 1000 0.3819 0.9554

Venus 233 720 15 0.9500 0.9524

Earth 275 295 0 1.000 1.000

Mars 170 300 0.006 0.5306 0.7188

Jupiter 123 313 10000 10.949 0.2422

Saturn 103 223 1000 9.1377 0.1246

Uranus 103 123 2 3.6837 0.2905

Neptune 103 123 7 3.5654 0.3790

Pluto 43 63 unknown 0.8946 0.2523

1. Which planet has the hottest temperature at night? ____________________ 2. Which planet is nearest earth in density? ____________________ 3. What are the radii of all the planets compared to? ____________________ 5. List the planets in order of surface pressure with the greatest pressure first and the lowest pressure

last.

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Interpreting a Circle Graph Below is a circle graph. The title of this graph is ―Earth‘s Surface.‖ Each segment has a name and a

percent value. Look at this graph, you can see that the pacific ocean covers 33% of the Earth‘s surface.

Land

29%

Artic ocean

3%

Other Seas

5%

Pacific ocean

33%

Atlantic Ocean

16%

Indian Ocean

14%

Try finding the following details on the graph above. 1. What percent of the Earth‘s surface is land? ___________________ 2. What total percent of the Earth‘s surface is covered by the two largest oceans?

______________________

3. What total percent of the Earth‘s surface is covered by water? ______________ 4. By comparing the amount of surface covered by water with the amount of surface covered by

land, what would you say would be the key point made by this circle graph?

THE EARTH’S SURFACE