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Bisc 102 Notes Chapter 1

How do we define life? What properties are common to all living organisms?

At what scales do we examine life?

How is the diversity of life organized?

What is the unifying theme of biology?

What is science? What is a theory?

What is biology? The study of life

All living organisms share seven properties:

A. OrderB. Regulation (body temperature, blood pressure, pH, etc.)C. Growth and developmentD. Energy utilizationE. Respond to the environmentF. ReproductionG. Evolution (all populations of species are able to evolve)

Life occurs at many scales and is hierarchical:

Cells- Tissues- Organ Systems & Organs- Organism- Populations- Communities-Ecosystems- Biosphere

(From cellular to global)

We are focusing on the organismal level which is the level of organisms on down.

Smallest-Scale Life: Cells

All living organisms are made of cells- Some of just one, some of many

All activities required for life occur at this level- Energy converted, production, waste disposed

Cells are programmed to divide- Allows for reproduction in all organisms- Allows for growth, replacement, and repair in multi-cellular organisms

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All cells hold DNAWhat is DNA?

Chemical that directs activities of the cell- A molecule that self-replicates and is passed on to new cells- Often referred to as a chromosome

*Professor will always refer to DNA as a chemical or molecule..

Made up of 4 bases occurring in a specific sequence A given base sequence makes up a gene

-functional unit that holds instructions for making a protein

e.g., pigment, insulin, hemoglobin, an enzyme

Two Cell Types

1. Prokaryotic-small, this is the original cell-DNA not contained

-No membrane-bound organelles

2. Eukaryotic-large-DNA contained by a nucleus

-many membrane-bound organelles

Large-Scale Life: Ecosystems

Two components:

1. Biotic(biological)- Producers- Consumers- Decomposers

2. Abiotic(non-living)- Rocks- Soil- Air- Water

Processes:

1. Nutrient Cycling- Biota take up from the environment, use, release or die, and make available again

2. Energy Flow

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- Plants capture light energy, and pass it along- Energy conversion is inefficient; some is lost from the system as heat

Many different kinds of ecosystems on Earth have led to a vast diversity of life forms.

Diversity of Life

Known life includes 1.8 million unique organisms- Although estimates of diversity range from 8 million to over 100 million

Organized into taxonomic groups base on:- Shared traits- Shared genes

Taxonomy: the identification, naming, and classification of organisms into categories:

Seven levels:

- Domain-broadest, inclusive- Kingdom- Phylum- Class- Order- Family- Genus- Species-most specific, exclusive

*A species is referred to by a two-part Latin name consisting of its Genus and species

Ex. Homo Sapiens

Three Domains of Life

1. Bacteria- Mitochondrion- Cyanobacteria- Gram-negative bacteria-

Chloroplast- Gram-positive bacteria- thermotoga

2. Archaea- Extreme halophiles- Methanogens- Hyperthermophiles

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3. Eukarya- Fungi- Animals- Cellular slime molds- Plants ciliates

All unicellular, prokaryotic

Uni- cellular and Multi- cellular eukaryotic

Unicellular prokaryotes:

1. Bacteria- found everywhere on Earth Pathogenic, beneficial; some decompose, somephotosynthesize

2. Archaea- discovered in the 1970s, typically beneficial; many inhabit extreme environments3. Eukarya Domain-

- Kingdom Animalia- produce energy by ingesting and digesting other organisms- Kingdom Plantae- produce energy by gathering sunlight (photosynthesis)- Kingdom Fungi- produce energy mostly by decomposing dead organisms- Protista- any that do not fit into the other 3 categories; very diverse; include unicellular and

multi-cellular forms (exp. Amoeba, slime mold, red algae, euglena, diatoms, and brown

algae)

Unity in the Diversity of Life

Although diverse, all life forms are made of cells that hold DNA DNA changes over time, causing changes in traits New traits that are favorable in a given environment p ersist, leading to diversity in life forms

*Unifying theme of life is that life evolves

Why and how does life evolve?

Charles Darwin: natural selection leads to descent with modification- Traits change over time Trait that provide a reproductive advantagefor a particular environment are selected- Adaptation Any kind of environmental pressure can lead to adaptation; nature selects the traits

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Conditions for natural selection:

In a given environment,

1. There must be a selection pressure ex. Overproduction lead to competition for limitedresources.

2. There must be genetically-based variation among individualsThese lead to unequal reproductive success among individuals.

*See Figure 1.12 in the book for an example.

Natural Selection and You

Pathogenic bacteria invade and multiply in your body and make you Your doctor prescribes an antibiotic that is specific to the bacteria Most bacteria die and the body recovers, but resistant bacteria survive

What ,is science?

From the latin verb meaning to know

Inquiry based way of gaining knowledge

- Ask why, what, how , where about natural phenomena- Limited to what we can observe, measure and test

Results from scientific exploration must be verifiable

- Leads to consensus about discoveries, which leads to scientific theories about natureChapter 2

Fundamentals of Chemistry for Non Biology Students

Matter-anything that has mass (exists in three states) *water the only element to exist in all 3

a. Elements- 92 naturally occurring in the worldi. 25 of these are essential to life

b. 4 of these make up our body (carbon, hydrogen, oxygen, and nitrogen)b. Atoms- the smallest unit of an elementc. Subatomic particles

Oxygen makes up 65% of your body.

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Carbon comes up next at 19%.

Four elements make up 96% of our body. Majority

7 make up 4%. substantial

And the other 14 elements make up 0.01%. trace

See Figure 2.2

Atoms

The smallest unit of matter that retains the properties of an element

Elements each are made up of their own kind of atom, with a unique configuration

Consist of a nucleus and shells, which hold an atoms subatomic particles

Subatomic Particles:

Atoms are made up of 3 particles, two of which carry a charge

In the nucleus:- Proton-positive charged(p+)- Neutron-neutral (n)

Orbiting the nucleus( in a shell)- Electron-negatively charged (e-)

Atoms have an equal num. of protons and electrons.

Isotopes: different atomic forms of an element

Elements are organized into the Periodic Table by the # of protons its atom have (atomic num.)

About Electrons:

Electrons of an atom orbit the nucleus from different levels: e- shells

Each shell holds a certain number of e-

- First, or innermost, shell is full with 2 e-- Second and third shells hold a maximum of 8

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An atom has as many shells as it takes to distribute its electrons

The farther away from the nucleus, the more energetic the electron

See figure 2.5

The outermost shell likes to be full or empty.

So the number of e- in the outermost shell dictates the chemical properties of an atom

Protons serve imp. Functions in the celll

Chemical Bonding

Bonds form as a result of atomic interactions ( which are based on the number of e- in the outermost

shell)

Atomic Level:

1. Ionic Bonds2. Covalent Bonds

Molecular Level:

1. Hydrogen Bonds

Ionic Bondso Atoms give up or take electrons to/from another atom to fulfill the shell requiremento disrupts the balance between + and and results in charged atoms, called ionso ex: H+( hydrogen ion, or proton)

Covalent Bondso Atoms share electrons to fill outer shellso Very strong bond between two or more atoms, which form molecules

*see figure 2.7

Polarity

When e- are shared unequally among atoms in the molecule Results when oxygen is involved; (electronegative)- Oxygen strongly attracts e- away from other atoms Charge is across the molecule is still neutral

Hydrogen Bonds

Bonds between polar molecules(not atoms)

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H-bond forms as an attraction between neighboring polar molecules

Neighboring water molecules are held together by H-bonds.

Chapter 2

(Chapter ?s)

What chemical properties of water make it life sustaining?

What about waters chemistry leads to its important properties?

What is pH? What does pH measure?

Whats an acid? Whats a base?

How is a stable pH of the bodys fluids maintained?

What is life support?

Much of the Earths surface is covered with water The human body is more than 70% water Cells range from 70-95% water Water has some unique properties, largely because of its polarity and H-bonding

Waters Unique Properties:

Occurs as a liquid, a solid, and a gas

1. Cohesion-a. The attraction of like molecules to like moleculesb. H-bonds cause water molecules to stick togetherc.

Important for internal transport in plants

d. Some animals can inhabit the surface of water2. Moderates Temperature

a. Temperature is related to heat, but different:b. Heat is energy associated with the movement of molecules in matterc. Temperature is a measure of heat, specifically, how fast molecules are moving

i. A rise in temperature means the avg. speed of movement has increased

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d. Water resists temperature change, which means it takes a lot of heat energy to changewater temperature

e. Why is water resistant to temperature change?i. Because of H-bonding:

ii. Added heat energy first must break H bonds, then water molecules can movefaster: T increases

iii. Releasing heat means H bonds reform, so water molecule movement slowsdown: T decreases

f. So H2O can absorb, store, and release a large amt of heat energy but changestemperature only slightly

i. The biological importance:1. Earths giant water supply helps maintain temperatures that permit life

g. Earth loses heat energy by evaporation; we lose heat energy by sweatingi. Regulates temperature: the fastest moving (highest energy) water molecules

vaporize, reducing the average speed of molecules left behind(T decreases)

3. Floats as a solida. Above freezing, H bonds are always breaking and reformingb. At or below freezing, H bonds become rigidc. Solid H2O is less dense than liquid H2O, so ice floats in liquid waterd. Ponds, lakes, and the oceans do not freeze solid

4. Versatile solventa. A solution is a liquid consisting of two or more substances evenly mixed

i. The dissolving agent is called the solventii. The dissolved substance is called the solute

b. When water is the solvent, the solution is aqueousc. Biological chemistry is wet= occurs in the aqueous fluids in the body

i. Within the cells, between cells, in blood plasmad. Why is water such a versatile solvent?

i. Because of its polaritye. Polar molecules and ionic compounds are water solubleor hydrophilic(water loving)f. Water insoluble molecules or compounds tend to be nonpolar and are

hydrophobic(water hating)

Acids, Bases, and pH

In aqueous solutions, some H2O molecules break apart into H+ and OH- ions:

H2O ___ H+ +OH-

In pure water H+ and OH- are equal.

Adding cetain substances can disrupt this normal balance

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pH is a measure of this balance; describes the concentration of H+ in a solution

-low H+ = high pH = basic

-H+ equals OH- = neutral

-high H+ = low pH = acidic

*See Figure 2.16

Change pH by adding

-acid: increases H+ of the aqueous solution by donating hydrogen ions

Ex. HClH+ Cl-

-base: decreases H+ of the aqueous solution by taking up hydrogen ions

Ex. NaOHNa+ + OH-

pH and Life

pH of a solution determines solubility and biological availability of dif. kinds of chemicals- nutrients (phosphorus, nitrogen, and carbon)- heavy metals (lead, copper, cadmium)

Determines how chemicals break down and whether products are of use in the body Some chemicals are toxic at lower pH because they are more soluble Buffers are chemical substances that resist pH change

o Accept H+ when H+ are in excesso Donate H+ when H+ are depleted

Biological fluids have built-in buffers to maintain pH Buffering can be overwhelmed

o Exp: ocean acidification, acidosisAcidosis- accumulation of acid in the blood

Two Types:- Metabolic acidosis- Respiratory acidosis

In acute cases, acidosis can lead to confusion, lethargy, coma, even death

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Chapter 3: The Molecules of Life

Which element is at the center of all molecules of living organisms?

What is a macromolecule? What kinds of chemical reactions build or break down macromolecules?

What is a biological molecule? What are the four dif.

Often shares electrons with other carbons to make various carbon skeletons

- Carbon skeletons vary in length- C.S. may have double bonds, which can vary in location

Simplest organic compounds are just hydrogen and carbon: hydrocarbons

Larger hydrocarbons are the main molecules in gasoline

Hydrocarbons of fat molecules provide energy for our bodies

Organic compounds occur in unique three-dimensional shapes

- Allows for recognition- Defines function

Shape (and function) of organic compounds depend on

- Carbon skeleton (# and organization)- Other groups of elements bonded to the skeleton-

Four Kinds of Biological molecules

1. Carbohydrates2. Proteins3. Nucleic Acids

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4. Lipids

Proteins:

Proteins make up the body and perform most of the functional tasks of the body Polymers constructed from amino acids monomers Tens of thousands of different kinds The most elaborate of lifes molecules

Different Kinds of Proteins: (figure 3.15)

a) Structural proteins provide supportb) Storage proteins provide amino acids for growthc) Contractile proteins function to move the bodyd)

Transport proteins move substances around

e) Enzymes assist, or catalyze, chemical reactionsProtein monomers: amino acids

All proteins are built from a common set of 20 amino acids Each has the same basic structure but differs in one way:

o The side group that they have*Amino acids are linked

* A small number of amino acids bonded together is a peptide; many together is a polypeptide. (figure

3.17)

Protein Structure::

Four levels:

The unique amino acid sequence is primary structure

1. Primary Sequence- makes a polypeptide2. Secondary structure3. Tertiary structure4. Quaternary structure

a. a protein has at least tertiary structure, and often quaternary structureStructure Affects Function

A change in primary structure can affect function. A single substitution can cause a serious disorder.

Higher-level structure

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Protein function depends on form, allows:- Recognition between molecules, and- Binding to other molecules

Changes in temperature and pH affect protein shape- Proteins can be denatured

Nucleic Acids

Nucleic Acids provide the directions for building proteins Two types:

DNA (deoxyribonucleic acid) store the instructions as genes RNA (ribonucleic acid) uses the instructions to build the proteins

Nucleic acids are polymers made up of nucleotide monomers:

- Sugar (5-carbon monosaccharide)- Phosphate group- Nitrogenous base- ( adenine=A, thymine=T, guanine=G, cytosine=C, and uracil= U)

Lipids

Carbon skeleton (straight or ringed) with H and O, and other elements Diverse, but all alike: they are hydrophobic (figure 3.10) Two types:

Fats Steroids

Fats

In the human body provide:- Energy storage- Cushioning, insulation

Take the form of the triglyceride: (see figure 3.15b) Triglycerides vary in fatty acid chemical structure, leading to:

oSaturated fats (saturated with hydrogen)

Have fatty acids with carbons bonded to a maximum number of hydrogens (only single bonds)

o Unsaturated fats Have fatty acids with carbons bonded to less than the maximum number of

hydrogens (double bonds)

*see figure 3.12

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*hydrogenation solidifies: makes trans fats

Steroids

Steroids are dif. From fats In structure and function

Carbon skeleton is fused into rings

Cholestorol is the base steroid

- Found in cell membranes- Precursor to sex hormones

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Chapter 4: Eukaryotic Cell Anatomy and Functions

Cell Theory

1. All living things are composed of cells2. All cells are formed from previously existing cells

All cells vary in size.

How do we see something so small?

With microscopes ( see figure 4.3)

- Light microscope- Electron microscopes (scanning)

Cells are diverse in type

Cells are diverse in function

Liver cells make enzymes

Immune cells produce antibioties

But eukaryotic cells are also alike

They all need to:

- Make energy and protein- Transport materials- Dispose of waste

And they all have these same features:

- Plasma membrane- Nucleus with DNA- Variety of membrane-bound organelles (organelle is a specialized subunit of the cell)

Animal Eukaryotic Cell

1. Plasma membrane and the cell surface- separates the living cell from its nonliving surroundings- Regulates the movement of chemicals into and out of the cell

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- Cell surface_ Extracellular matrix: sticky external coat secreted by some cells; holds cellstogether; protects and supports cells

- Cell junctions: connect cells to coordinate interactions in tissues2. Cytoplasm

- Space between the nucleus and the plasma membrane, filled largely with cytosol3. Cytoskeleton

- The infrastructure of the cell: microtubules, filaments- Cilia and Flagella_ appendages of some cells: cytoskeleton extensions that aid in movement- Cilia move in a coordinated back and forth motion- Flagella propel the cell with a whipping motion

4. Mitochondrian- Site of energy production: cellular respiration- chemical energy converted to cellular

energy(ATP)

- Double membrane5. Nucleus and ribosomes

- Nucleus: control center where DNA and RNA are located- Ribosomes: sites of protein synthesis

Two kinds: Cytoplasmic ribosomes-produce proteins to be used in the cell E.R. Ribosomes- produce proteins to be used elsewhere

6. Endomembrane system- Structure: internal membrane divided into a system of organelles

Endoplasmic reticulum- Primary factory of the cell Produces diversity of molecules Membrane within the cytoplasm divided into a maze of tubes and sacs

o Two kinds: Rough ER and Smooth ER Golgi apparatus

Receives products of the ER Then refines, stores, and distributes the final product

Transport vesicles (figure 4.12) Membrane sacs that move materials around in the cell

Lysosomes Sacs of membrane holding digestive enzymes Digestive functions:

o Break down damaged organelleso Digest food particles

Vacuoles Sacs of membrane that bud from the ER, Golgi, or plasma membrane Different kinds of vacuoles:

o Food vacuole: bring food molecules into the cell

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o Contractile vacuole: pumps watero Storage vacuole: in plants the central vacuole is this

- Functions: manufacture and distribute cellular productsa. Consist of several organelles

All eukaryotic cells need to make energy & proteins (lipids)

- Mitochondrian- Nucleus and ribosomes and endo. System- Transport material, dispose of waste- plasma membrane +cytoskeleton +vesicles

Chapter 5: The Working Cell

Energy Concepts

Energy = the capacity to do work Can only be converted from one form to another, never created or destroyed

The principle of conservation of energyPotential Energy=energy in storage

Kinetic Energy=energy of motion (ex. Heat)

Potential E. in chemicals

- Stored in moleculeso Arises from the arrangement of atomso Hydrocarbons, carbohydrates, and fats store a lot of energy

Potential chemical:

Energy in gasoline (octane) kinetic energy (+heat)

Energy is measured in calories (cal)

Chemistry:

A calorie (cal) is the unit of energy needed to raise temperature of 1g of water by 1 degree C

Nutrition:

A kilocalorie (Cal) is a unit of energy needed to raise the temperature of 1kg of water by 1 degree C

We get energy from food: Figure 5.3

Cellular workers:

1. ATP

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a. Chemical potential energy for the cell2. Enzymes3. Plasma Membrane

a. Regulates transport into and out of cellATP: adenosine (ribose+ adenine) and three phosphates

1. ATP: adenosine triphosphatea. How is ATP energy? The bonds hold energy (Figure 5.4)

2. ATP is continuously renewed:a. Upon release, a third P binds again with ADP to make more ATP

3. Rate of ATP production:a. 10 million molecules/sec/cell

Phosphate transferred to target molecules:

1. Mechanical worka. Motor proteins accept the P to change shape and contract (Figure 5.5a)

2. Transport worka. Proteins in membranes accept third P and pump ions across the membrane (Figure 5.5b)

3. Chemical worka. Monomers accept third P to build polymers (Figure 5.5c)

Enzymes

Enzymes are specialized proteins that assist in chemical reactions Specific to a particular reaction Thousands of different kinds Used over and over again Identified by name: end inase Enzymes lower the energy required to activate a reaction (activation energy) Figure 5.7

o How do enzymes do this? 1. Enzyme available with empty active site 2. Substrate bindsto enzyme 3. Substrate is converted to products 4. Products are released

Induced fit- upon binding the enzyme and substrate change

Sucrose+sucrose+water glucose+fructose+sucrose ------hydrolysis reaction

An enzyme decreases the energy required to activate the reaction.

Enzymes can be inhibited

Inhibitors disrupt enzyme function:

1. Substrate imposters(competitors)

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2. Active site deactivatorsThe Plasma Membrane

Separates the internal environment from the external environment; controls transport inand out

A foundation made of:o Phospholipidso Two-tailed fatty acid lipid

In a phosphate heads are hydrophilic, but the lipid tails are hydrophobic

In an aqueous environment:

The water-loving phosphate heads orient towards water

The water-fearing lipid tails orient toward each other, away from water.

The phospholipids orient to create two layers, called the phospholipid bilayer

*oxygen and carbon dioxide move through the membrane freely bc theyre small and nonpolar

1. Phospholipids ( bilayer, the foundation)

2. Proteins embedded in the bilayer

Fluid Mosaic Model

Plasma membrane is semi-permeable, or selectively permeable: only some substances freely cross

Water can also move freely through the plasma membrane bc of the fluidity of the membrane that

creates little gaps that water can seep through.

Membrane Processes

1. Passive transport- movement from a high to low concentration (down a concentration gradient)a. Diffusion(solutes move)b. Osmosis(water moves)

2. Active transport- movement from a low to high concentration (pumping of molecules)3. Large molecule transport4. Chemical signaling

Diffusion- dissolved solutes move from high to low concentration (down the gradient):

Figure 5.12a

Facilitated diffusion: movement of solutes through a channel (a membrane protein)

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Figure 5.11

Osmosis (diffusion of water)

Membrane is permeable to water but not to solutes Water moves to equalize solute concentration

o Water goes where solute are of high concentration The volume of water changes on the two sides of the membrane

o See Figure 5.13 Osmosis works to maintain solute and water balance in cells (70-95% water)

o Solutes in solution=solutes inside cell (Figure 5.14)o A. Isotonic- cell is normalo B. Hypotonic- cell will burst (lysing)o C. Hypertonic cell will shrivel

And in blood and the fluid surrounding cells of tissueso At the body level, the urinary system does the job of regulating water and solutes

Water and solutes from the blood are filtered and reabsorbed The wasted is collected to make urine, which is excreted

Active Transport

Use energy (ATP) and proteins Molecules pumped against the solute concentration gradient Figure 5.16

Transport of Big Molecules: (Figure 5.18)

Exocytosis: molecules exit the cell Endocytosis: molecules enter the cell

*see page 88

Cell Signaling

Form of communication Cells receives a signal from outside Initiates a signal transduction pathway: Figure 5.19

Chapter 21: Animal Structure and Function

Generally, how does form relate to function in living organisms?

What tissues make up the body?

Form Fits Function

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Biological equipment is refined to serve a purpose within an organisms environment (Figure21.2)

See Figure 21.1 for example of the human body Understanding the relationship between form and function is the focus of:

o Anatomy: study of the structure of an organism and its partso Physiology: study of the function of the structures

Tissues

An integrated group of similar cells that performs a specific function Cells are specialized and held together in some way, such as

By a net of fibers By sticky substance By special junctions

Four types of tissues:o Epithelialo Connectiveo Muscleo Nervous

Epithelial tissue (Figure 21.3) Structure: sheets of tightly packed cells Function: protect, absorb, secrete Covers the body surface; lines orgasms and cavities of the body Surface epithelium is continuously renewed

Connective tissue (Figure Structure: sparse population of cells scattered through an

extracellular matrix

o Extracellular matrix- a web of protein fibers embedded in afoundation (liquid, jelly-like, solid)

Function: binds and supports other tissues (most widely distributedof all)

o Six kinds of connective tissue (Figure 21.4) Loose- cells in a semi-fluid matrix with a loose

weave of collagen and elastic fibers; bind

Adipose- dense within a jelly-like matrix of sparsefibers; store

Blood- cells suspended in an aqueous liquid matrix(plasma); transport

Fibrous- fewer cells in a dense matrix of bundledcollagen fibers (tendons, ligaments); connect

Cartilage- dense gel-like matrix with thin collagenfibers; cushion

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Bone- matrix of rubbery collagen fibers hardenedwith calcium salts; support

Muscle Tissue Most abundant of all tissues in most animals

o Bundles of long thin cells (muscle cells)o With cellular proteins arranged to contact when signaledo Three types:

Skeletal Cardiac Smooth

Skeletal Muscleo Contractile apparatus of the cells

(fibers) form a banded pattern:

striated (striped) Figure 21.5

o Attached to bones by tendonso Action of skeletal muscle is

voluntary movement

Cardiac Muscleo Fibers striated, but also branched

and joined to one another

Allows for quick signaling toall muscle cells at once

Heart contracts in acoordinated heart beat

o Contraction of heart muscle isinvoluntary

Smooth Muscleo Fibers are not striatedo Found in walls of organso Contraction is involuntary

Nervous Tissue Made up of nerve cells (neurons) that have long extensions Found in the brain, spinal cords, nerves Transmit electrical signals, fast and in some cases, over long

distanceso Nervous Tissue (Figure 27.17)

Sensory receptors receive input, transmit the signal,and the body responds

Organs

Two or more tissues packaged into one working unit that performs a specific function

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o Examples: small intestine, heart, liver, stomach, brain, bone Another example is blood vessels: arteries & veins (figure 23.8)

Organ Systems

Multiple organs work together to perform vital body functions Survival depends on the coordination of all organ systems Failure of any one organ system jeopardizes the entire body

o Names Integumentary Respiratory Circulatory Digestive Excretory Reproductive

Endocrine Lymphatic/Immune Muscular Skeletal Nervous

* go to pp. 462-463 for an overviewChapter 21(II) Questions

What is an open system? How are open systems designed to support exchange?

How is the bodys internal environment regulated?

How do negative and positive feedback mechanisms of regulation differ?

How are temperatures and water/solute balance maintained in the body?

How is the urinary system structured to

The Open System

Organisms continuously exchange chemicals and energy with the environment Nutrients and oxygen enter, wastes produced by metabolism exit Exchange occurs at all biological levels

o The smallest scale=the cellExchange: Size and Shape Matter (Figure 21.9)

What about longer, more complex organisms?

How do they meet the demands for exchange that come with increased size?

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- Layers of cells are folded or branched to maximize surface area (relative to volume) tosupport exchange

- Branching or folding tissues increases surface area for a given volume; maximizes exchangeExchange involves Organ Systems

- Figure 21.11Exchange requires regulation:

- In openHomeostasis: a dynamic state (Figure 21.12)

Homeostatsis

- Dynamic state maintained mostly by processes under negative feedbackcontrolo A change in a condition triggers a processo The result of the process feed back to inhibit the processo Brings the condition back to the norm

Ex: body temperature, food digestion, water-solute balance, insulin production,etc.

Negative Feedback: Room Temperature

The results of a process inhibit that very process.

*Signal: temperature drops below set point

*The process: heat released

*Results: temperature increases, process stops

Positive Feedback

A process is initiated, but the results intensify the process

Less common in animals

Example: childbirth contractions

* Signal: pressure from fetus

*The process: chemicals released

*The result: muscles contract

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1. Thermoregulation (regulation of temperature)a. Among animals:

i. Ectotherms do not regulate body temperature-conform to the environmenttemp

1. Fishes, reptiles, amphibiansii. Endotherms derive body heat mostly from metabolism

1. Mammals, birdsb. See Figure 21.4

2. Osmoregulation (regulation of water)a. Living cells depend on precise balance ofwater and dissolved solutesb. Many animals must osmoregulate: control water and solute balance in the bodyc. Based largely on regulating solutes; water moves according to solute concentration

(osmosis)

i. Osmoregulation in Land Animals1. Gain water by eating and drinking2. Lose water by breathing, perspiring, wasted elimination3. Metabolism of fats, sugars, and proteins produces wastes4. Must maintain proper iron concentrations (e.g., Na+, K+,H+)5. The regulation of water and solutes is the job of the urinary system

(see Figure 21.17)

ii. Urinary system1. Kidney- filters blood, concentrates wastes in excess water2. Ureter-the tube by which urine leaves the kidney3. Urinary Bladder-where urine is stored4. Etc.

a. The Kidneys: the main processing center of the urinarysystem ( see Figure 21.17)

i. The functional unit of the kidney is the nephronii. Millions of nephrons amounts to 100s of miles of

tubules in each kidney

iii. Valuables reclaimed, waste goes to the collectingduct

b. Processes of the Nephron (Figure 21.18)i. Filtration: blood pressure forces H2O and small

molecules from blood plasma; filtrate collects in the

tubule

ii. Secretion: wastes not initially filtered arepumpedinto the filtrate

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iii. Reabsorption: H2O and valuable solutes arereturned to the blood (excess water, wastes collect

in the collecting duct as urine)

iv. Excretion: urine leaves the kidneys and the bodyiii. Urinary System Regulation

1. These processes of the nephron are under control of hormonesa. When water content is low, brain signals secretion of anti-

diuretic hormone (ADH)

b. Water content increases and ADH secretion stopsGood Kidney Health is Essential

200 quarts of blood are processed by the kidneys every day; 2 quarts of fluid excreted, restis reabsorbed

In a single heartbeat, 20% of the bodys blood flow goes to the kidneys

Kidney health is essential to good health Prevent diabetes and high blood pressure

o Maintain a healthy weight, eat well, exerciseKidney Failure

Can result from unmanaged diabetes, high blood pressure, infection or injury Body can not eliminate waste

Treatment for Kidney Failure: Dialysis

See Figure 21.19

Chapter 22: Nutrition and Digestion

Food Processing

Food processing takes place along the alimentary canal as series of four steps (Figure 22.15) Food moves through the canal byperistalsis

Two Kinds of Digestion

Digestion dismantles food particles by:

1. Mechanical digestion: a physical process2. Chemical digestion:

Chemical Digestion:

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- Hydrolysis reactions are assisted by enzymes; as a group, we refer to them as hydrolases(Figure 22.3)

Human Digestive System

- The Mouth (Oral Cavity) Figure 22.6o Functions in processing:

Ingestion Digestion (mechanical + chemical): chewing is mechanical digestion, the tongue

moves food, salivary gland duct secretes salivary amylase: chemical

digestion(carbohydrates only)

- The Pharynx (Figure 22.7)o Connects the mouth to the esophagus, but also opens to the trachea (wind pipe)o Epiglottis closes the trachea entrance during swallowing

- The Esophaguso A muscular tube that connects the pharynx to the stomacho Food moves via peristalsis: the rhythmic, involuntary contraction of smooth muscle

tissue (Figure 22.8)

Here and throughout the digestive system Food moves in one direction

- The Stomach (Figure 22.9)o Food storageo Mechanical digestion: food churned into chymeo Chemical digestion: secretes gastric juice

Strongly acidic(HCl) Digestive enzymes(proteins begin digestion here)

o Produces mucus for protection Stomach Related Ailments

1. Heartburn, acid reflux: backflow of gastric juice into the esophagus2. Gastric ulcers: tissue is eroded by gastric juice

a. Most caused by bacteria that damage mucusb. Severe cases may result in a hole, leading to internal bleeding

and infection

The Small Intestineso Small in contrast to the large intestineo The longest part of the alimentary canal (20ft)o Receives chyme from the stomacho Regions are specialized to perform specific functions

The duodenum of the small intestines Specialized to complete digestion Receives chemicals from accessory organs:

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o Pancreas: secretes neutralizing juice with various hydrolaseso Liver: secretes bile, which breaks down fats (bile is stored in the

gallbladder)

Enzymes at work in the duodenum Carbohydrates

o Pancreatic amylaseo Sucrase, Lactase (disaccharides broken

down into monosaccharides)

Proteinso Proteases- break down proteinso Peptidases- digest peptides to amino

acids

Lipidso Lipases- digest fats that have been

emulsifiedfirst by bile

The Rest of the small intestine(Figure 22.13)o Next several feet are specialized for absorptiono Wall is folded, with extensions of the tissue called villio Cells of each villus have their own extensions: microvillio Provides large surface area for the absorption of nutrients

Cells with microvilli take up nutrients Nutrients move to interstitial fluid, then to blood Blood transports nutrients elsewhere in the body

The Large Intestine (Colon)o Wider and shorter than the small intestine

Absorbs water, dissolved ionso Home to diversity of mostly harmless bacteria

Produce some vitamins Release gases

o Waste left over is feces Stored in rectum, eliminated by anus

Second Half of Chapter 22: Nutrition

Food is potential chemical energyo Your cells convert food energy into ATP: another form of potential chemical energy

(Figure 5.3b)

Food Provides Energyo Energy from food (measured in Cal) supports metabolism of the body (all chemical

reactions)

o The amount of energy that the body uses per day is metabolic rate Some to support basic body functions (basal metabolic rate, BMR)

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o Metabolic rate varies widely among people: BMR depends on age, sex, heredity, body size (on avg., ranges from 1300-1800

cal/day)

Everyones activity level is different (Table 22.1) Unused calories are stored as fat

Food provides Raw materialso Cells build organic molecules to make new cells and to support cellular activitieso Digested food provides raw materials to be reassembled into new biomolecules

Proteins and DNA Food provides essential nutrients

o Substances the body cannot make: Essential amino acids Vitamins Minerals Essential fatty acids

Essential Amino Acids:o Of the 20 amino acids, 8 cannot be made by the bodyo Deficiency leads to degradation of proteinso Different foods vary in amino acid content

Animal proteins are complete (have all 8) Most plant proteins are incomplete (deficient in 1 or

more)

Vitaminso Organic molecules required from the diet in small amountso Most function to help enzymeso Two kinds:

Water soluble (most B vitamins, vitamin C) Fat soluble (vitamins A, D, D, and K) *see table 22.2

o Recommended daily value (RDV) established to preventdeficiencies

Mineralso Inorganic substances required from the diet

Essential fatty acidso Cells make fats and other lipids by linking fatty acids with other

moleculeso Essential fatty acids are those the body cannot makeo Polyunsaturated fats ( >one double bond)o Two families:

Omega-6 Omega-3

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o Regulate body functions such as heart rate, blood pressure,blood clotting

o Deficiencies linked to a wide range of serious health conditions

Nutrition and Digestion (Chapter 22 cont)

Health and Diet

Many health conditions that reduce the quality of life and shorten lifespan are linked to diet:o Heart healtho High blood pressureo Diabeteso Cancero Digestive disorderso Eating disorderso Food allergies/intoleranceso Excess weight

USDA 2011 Dietary Guidelines

Overall eat less, avoid oversized portions Eat more healthy foods Eat less sodium, saturated and trans fat, added sugars, and refined grains Drink water, not sugary drinks Balance calories with physical acitivity

Packaged food is labeled with nutrition details: (in order of abundance)

Start Here

Energy per serving Energy from fats

Limits nutrients In gold Quick guide to % Daily Values

20% or more is high 5% or less

is low

Maximize nutrient I blue

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Nurtitional Disorders

Malnutrition health problems from an imbalanced or insufficient diet (ex: protein (aminoacid) deficiency

Usually results from a shortage in food supply Also results from eating disorder, e.g., anorexia, bulimia Obesity results from excessive food intake

o Associated with chronic disease (increases risk of heart attack, diabetes, and otherillnesses)

o Body mass index (BMI) is a rough measure of weight healtho To some extent, a tendency toward obesity is inherited

Chapter 6: Cellular Respiration

How does life run on solar energy?

How does cellular respiration convert energy?

What are the steps, the reactants, the products?

What is the role of oxygen?

What is the role of electrons?

How does your body make energy when it doesnt have a lot of oxygen?

What is fermentation?

Figure 6.2

- Sunlight energy enters ecosystem- Energy flows: enters as sunlight, exits as heat- Chemicals cycle: glucose and oxygen, carbon dioxide and water

Photosynthesis: the process by which light energy is converted to chemical energy

Cellular Respiration

A biochemical pathway of the cell that converts energy in food to ATP An aerobic process: it depends on O2 CO2 and H2O are waste products Respiration is the process that exchanges O2 and CO2

How is energy converted?

o Electrons: subatomic particles that are energizedUsing electrons:

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Controlled step-wise transfer from glucose to oxygeno Picked up by carrierso Through proteins in the mitochondrion

Oxygens Role in e- Transfer

1. An electron-grabber, oxygen attracts electrons through all steps of the pathway2. Accepts spent electrons at the end of cellular respiration (along with H+, makes H2O)3. Binds carbons released from glucose break-down (makes CO2)

Steps of Cellular Respiration: (Figure 6.6)

In the cytoplasm:

1. Glycolysisa. Glucose from digestion of your French fries broken down here, in the cytoplasmb. Uses 2 molecules of ATPwhy?c. Releases

i. Pyruvic acid (goes to step 2)ii. Electron carriers (go to step 3)iii. 4 ATP molecules (by e- transfer)iv. No waste

In the mitochondria:

2. Citric Acid Cycle (CAC)a. In the mitochondrion, pyruvic acid molecules from Step 1 are broken downb. Electrons are transferred to carriersc. Releases:

i. Electron carriers (go to step 3)ii. 2 molecules ATP (by e- transfer)iii. CO2 (waste, exhaled)

3. Electron Transport Chaina. In the mitochondrion, electrons from steps 1 and 2 accepted by protein molecules

spanning the inner membrane

b. Energy released by electron transfer used to pump H+ across the membrane: creates aconcentration gradient

c. As H+ flows back across the membrane, binds ADP+P to make ATP

In the absence of O2: Fermentation

ETC

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Anaerobic conversion of food enery Glycolysis continues, but lactic acid is the product E- are not sent to ETC; steps 2 and 3 do not run Very little ATP produced Short-term emergency metabolism

Fermentation by Microorganisms (Figure 6.16)

Microorganisms get energy by fermentationo Bacteria ferment and produce lactic acid

Cheese,sour cream, yougurt from milk Yeast ferment and produce ethyl alcohol, release CO2

o Beer, wineo Bread

Circulation and Respiration (Chapter 23)

What is the function of the circulatory system?

What parts make up this system?

How are the parts of the system structured?

How do they function, both separately and together?

Circulatory System

Function is transport, to serve the cello Oxygen/carbon dioxide, nutrients, wastes

An organ system consisting of three parts: Heart (cardio) Blood vessels (vascular) make up cardiovascular system blood (circulates to transport, is a tissue not an organ)

confined to vessels: closed system Heart pumps blood via a system ofvessels; functions to maintain homeostasis by:

Controlling chemical balance Controlling blood composition Distributing hormones Defending against foreign invaders Regulating body temperature

1. Heart (Figure 23.4)a. Muscular organ that functions to pump blood to the lungs and to the bodyb. Regularly contracts (systole) and relaxes (diastole)

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i. Pumps blood out, flows back inii. Heart rate set by the sinoatrial (SA) node, averages 60-80 bpm

c. Valves ensure that blood flows in the right direction2. Blood Vessels (Figure 23.8)

a. Arteries: carry blood away from the heartb. Veins: carry blood to the heartc. Capillaries: tiniest, thinnest vessels; occur in clusters to make capillary beds (F 23.9b)

i. Designed for local exchangeii. Very thin with a high surface area to volume ratioiii. Leaky, which allows for exchange between bl ood and interstitial fluid by

diffusion

iv. Cellular respiration in the cell demands O2, produces CO2 as wastev. So in the cell: concentration of O2 is lower than outside; and CO2 concentration

is higher than outside

vi. O2 and CO2 exchanged by the process of diffusion3. Blood

a. Adult circulatory system carries about 11 pints of bloodb. Composition: (Figure 23.11)

i. Plasma (mostly water)ii. Cells (mostly red blood cells)

c. pH: 7.35-7.45d. Cellular Elements of Blood: (Figure 23.12)

i. 45% of blood is made up of:1. Red blood cells that transport O2 to support cellular respiration2. White blood cells fight infections and cancer3. Platelets, for clotting

How do RBCs transport O2?

Their structure supports this function:o High surface area to volumeo Lack nuclei and other organelleso Loaded with 250 million molecules of hemoglobin

A protein made up of 4 polypeptide subunits; each subunit has heme iron at thecenter, binds to O2

*Anemia: low iron low hemoglobin low O2 delivery

Origins of blood cells

Stem cells of bone marrow differentiateo Into RBC, WBC, and cells that become platelets

Red blood cells mature when signaled by the hormone EPO

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When oxygen in tissue is low, kidneys release EPO, which boosts RBC productiono Trigger: oxygen low=RBC count below set pointo Process: EPO released, RBC producedo Results: RBC returns to set point, EPO stops

Double circulatory system: two paths to blood flow (Figure 23.3)

Which vessels carry O2 rich blood?

Depends on the circuit:o In the pulmonary circuit, arteries carry blood away from the heart to the lungs

Pulmonary arteries carry O2 poor blood Pulmonary veins carry O2 rich blood

o In the systemic circuit, arteries carry blood away from the heart to the body Arteries(aorta) carry O2 rich blood Veins (vena cava) carry O2 poor blood

Blood Pressure

The force that blood exerts against blood vessel walls A function of cardiac output and blood vessel resistance Measured in arterial pressure at systole and at diastole

o Optimal blood pressure is 120/80 mmHg Varies a lot, affected by all kinds of things Hypertension is high blood pressure

o Average reading of >140/90 mmHg Often asymptomatic, goes undiagnosed Blood vessel walls weakened; increases risk of atherosclerosis

o If uncontrolled, can threaten lifeo Controlled by diet, exercise, medication if necessaryo Plaque: an accumulation of cholesterol and other substances (figure 23.14)

Atherosclerosis can lead to:o Heart attack: coronary arteries blockedo Stroke: a blockage in the brain

Respiration

The process of exchanging O2 and CO2 in support of cellular respiration Occurs in three phases:

o Breathing (air flows in and out of the body)o Transport (via circulatory system)o Service to the cell

Depends on a moist surface in contact with both air and capillaries: respiratory surfaceo Respiratory surface is the site of exchange with the external environment (Figure 23. 17)

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The Human Respiratory System (Figure 23.19)

Cells of the respiratory system have cilia and produce mucus, which help to remove debrisfrom the respiratory system

Breathing: alternating process of inhalation-exhalation (Figure 23.20)o Creates negative pressure so that air flows in

Breathing is regulated (Figure 23.21) brain regulates breathing by monitoring CO2Lung Health

Every breath exposes respiratory tissue to potentially damaging chemicals Tobacco smoke is a serious source of airborne pollutants

o Irritates the cells that line the respiratory systemo Inhibits ability to remove foreign substances from the airway

Smoking kills about 440,000 Americans annually: (Figure 23.24) Lung cancer COPD ( chronic bronchitis, emphysema)

Risk factors for disease of the circulatory and respiratory systems

Genetic predisposition Poor diet (high in salt, fat) High cholesterol Sedentary lifestyle

Tobacco smoking (especially for diseases of the respiratory system)

Chapter 10: DNA

How are DNA and RNA structured? How are they alike? Different?

Why and how does DNA replicate?

How do DNA and RNA work together? What is the outcome of this partnership?

What are the mutations and the consequences of mutations?

What are viruses? How do they relate to DNA?

Nucleic Acids:

o Two kinds: DNA and RNAo DNA is always in the nucleus; RNA is made there but goes out to the cytoplasm

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o Function: to make proteinso DNA segments code for proteins ( genes)o RNA makes proteins at the ribosomes

o Polymers made up of nucleotide monomers:o 5 kinds of nucleotides, each defined by a nitrogen-containing base: (Figure 3.24)

o Adenine*o Guanine*o Cytosine**o Thymine**o Uracil**

* = purines: adenine and guanine (double ringed bases) ** = pyrimidines: single ringed bases

o These four make up RNAo Many nucleotides: polynucleotide

o How are nucleotides linked together? (Figure 10.1)DNA

Deoxyribonucleic acid (Figure 10.5) Sugar: deoxyribose Nucleotides: A,G, T, C Two polynucleotide strands (double stranded) Holds the genetic code (for making proteins) Structure discovered in 1953 by Watson and Crick DNA is made of two complementary polynucleotide strands

Linked by H-bonds between bases of the nucleotides A base of one strand always pairs with a specific base of the other strand, according to this

base pairing rule:

A bonds to T G bonds to C

Each molecule of DNA is made up of thousands of base pairso Each has its own unique sequence of bases (ex. ACTGACCAGTCGA)

The human genome is made up of 23 molecules of DNA (n) All but one kind of cell has 2 copies of each (2n) (the sex cell only has one) Molecules of DNA are divided into functional units,, each with a unique base sequence: genes

o A given gene codes for a specific polypeptide; a molecule of DNA has many genes(Figure 10.10)

How can so many molecules of DNA fit in the nucleus of a cell?o A: DNA molecules coil up around proteins, making chromatin (Figure 4.9)

At specific times in the life of a cell, chromatin condenses into chromosomes:DNA Replication

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o DNA is the hereditary chemical of lifeo To be passed on via new cells, it must be replicated exactlyo Each strand of a DNA molecule serves as a template (Figure 10.6)o DNA polymerase facilitates replication (Figure 10.7)

o Breaks open an existing moleculeo Brings nucleotides that match the template sequence (A T, GC)

RNA

o Ribonucleic acido Single strandedo Sugar: riboseo Nucleotides: A,G, U, Co Different kinds with different functions; ex. mRNA delivers DNAs message to ribosomes for

protein synthesis

DNA and RNA are partners

o DNA stays in the nucleus, but proteins are made in the cytoplasm, at the ribosomeso RNA goes out to the cytoplasm to direct protein synthesiso This process occurs in two steps: (Figure 10.8)

Transcription Translation

Two steps to Protein Synthesis

In the nucleus, a gene(DNA) is transcribedinto a molecule of RNA (Figure 10.10) At a ribosome, the message of RNA is translatedinto a polypeptide

o Transcription DNA is transcribed into messenger RNA (mRNA); RNA polymerase assists:

(Figure 10.13a)

mRNA takes the message to the ribosomes where it is translated Before leaving the nucleus, mRNA must be processed (Figure 10.14)

Caps and tail added Introns(junk code) removed Exons (effective code) spliced together

o Translation The language of mRNA is translated into the language of proteins at the

ribosome

The base sequence of mRNA is read in groups of three: triplet codons- eachcorresponds to a specific amino acid (Figure 10.10)

The genetic Code: The bases of RNA combine in different ways to make 64 triplets

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20 amino acids, each coded for by a codon (no ambiguity, someredundancy)

o Triplet codon: A U A (Figure 10.11) One start codon and three stop codons

mRNA attaches to a ribosome and a translator, transfer RNA (tRNA) reads it,codon by codon

tRNA brings the right amino acid to the ribosome and they link, one by one initiation (start codon) elongation termination (stops codons)

Mutationso Any change in the nucleotide sequence of DNAo Can involve large regions of DNA or just a single nucleotide pairo DNA polymerase (and other proteins) are tasked with correcting mutationso If not fixedx, mutations vary in effect

Inconsequential, positive, negative, lethalo Two categories:

Substitution (Figure 10.22a) May be lethal Impair function Go undetected

Insertion/Deletion (Figure 10.22b) Often disastrous reading frame shifts, code becomes nonsensical

Causes of Mutation Errors in replication Exposure to mutagens: physical or chemical agents that cause mutations

Toxic chemicals X-rays UV rays (sunlight and lamps)

o Are mutations always bad? Source of diversity of life

Natural selection acts on traits that result from changes at the geneticlevel

Genetics make use of mutations in the laboratory to learn more about genetics Viruses: Are they life? (Figure 10.24)

o Show some, but not all, characteristics of living organisms Have genes Do not utilize energy Do they respond to the environment?

o Persist only by infecting a living cell

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o Kinds of Viruses DNA or RNA covered by a protein coat: genes in a box (Figure 10.24) Type/structure varies according to host

Bacterial: inject viral DNA or RNA into host cell Plant: use vectors to infect cells with viral RNA Animal: surface aids to infect with viral DNA or RNA

Virus Diversity: DNA or RNA + protein coat Bacteriophage(DNA,RNA) Plant viruses (RNA)(rod shaped) Adenovirus (DNA) (polyhedron shape) Enveloped virus (DNA,RNA) Pox virus (DNA) (brick shape)

o Virus Replication Acellular so cannot reproduce the way cells do Must use host cell machinery and materials:

Make more nucleic acid Persist in different ways Figure 10.26

1. Nucleic acid replicates, virus is latent 2. Bursts from the cell (cell death) 3. Viral body leaves by budding within cell membrane

o Mechanisms of Disease Some viruses lyse host cells, which causes death of the cell

Whole organism may suffer if enough cells dies Some disrupt homeostasis, leading to disease Some viral genes code for toxins

o Human Immunodeficiency virus Figure 10.32 An enveloped virus A virus that persists by its RNA being transcribed into DNA is called a retrovirus

o Acquired Immunodeficiency syndrome HIV infects white blood cells, which impairs immune system AIDS results from secondary Medication extends life, but does not rid the body of the virus Anti-HIV drugs interfere with virus reproduction

Inhibit reverse transcriptase (AZT) Inhibit proteases

o Viral Illness Common ailments

Cold, flu, chickenpox, cold sores Serious disease

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Ebola, avian influenza, SARS (severe acute respiratory disorder) Maybe caused by virus

Multiple sclerosis and chronic fatigue syndromeo Viruses and Cancer

Many viruses are linked to cancer: Human papillomavirus (cervical in women) Hepatitis-B and hepatitis-C (liver) Epstein-Barr virus (lymphomas) Human T-lymphotropic virus (adult leukemia)

o Transmission of Viruses Vertical: mother to child Horizontal: organism to organism

Exchange ofblood, saliva Breathing in droplets of aerosols

Contaminated food or water Insect vectors

o Human Defense Personal protection, vaccinations

Prevent infection Immune system

Once infected, immune bodies attack virus Antiviral drugs

Inactivate viruss newly synthesized DNA Why do antibiotics NOT work against viruses? B/c they work against living

germs and viruses are not considered to be living

Chapter 8:

Cellular Reproduction: Cells from Cells

Why do cells reproduce?

What are the two ways of cell reproduction? Why are there two? Why not just one?

What happens to DNA during cell reproduction?

Biological Reproduction

o Asexual (Figure 8.1)o Occurs by simple division of a somatic cell (body cell)o Offspring DNA identical to parent DNA

o Sexualo Requires two specialized cells: gametes (or sex cells)o A sperm fertilizes an egg (contributes its DNA to the egg DNA

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o Offspring DNA is unique Eukaryotic Cell reproduction

o Two processes, different purposes: Mitosis: cell replacement and growth, asexual reproduction

Limited to body(somatic) cells DNA replicates and is passed on New daughter cells are genetically identical

Meiosis: for sexual reproduction Starts with a specialized body cell, the product: sex cells (gametes) DNA replicates, but then is mixed up and then divided in half twice New cells have half the DNA of the starting cell, and are genetically

unique

o Body Cell Cycle Starts with birth of a cell division to two daughter cells An orderly sequence of events, consisting of two phases:

Interphase: 90% of cell lifeo For most of the life of the cell, DNA occurs in chromatin form,

that is, as single molecules wrapped around proteins.

o With DNA in chromatin form: The cell does its job Prepares for division:

Protein, organelles of the cytoplasm increase innumber

Cell grows in size Each molecule of DNA replicates For cell division: the two daughter molecules

are called sister chromatids

Chromatids will separate and be distributedbetween daughter cells during mitosis

Mitotic Phase(figure 8.6)

Missed Friday, Nov 11

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Chapter 8:

Through what cell division process are sex cells made from the body cells?

How is genetic variation in sex cells created?

What happens when sex cell reproduction goes awry?

Why sexual reproduction?

It creates genetic variation Offspring inherit a unique combination of genes from two parents You dont look exactly like your parents or your siblings

DNA in Humans

Human genome has 23 molecules of DNA (n=23) Include the autosomes(1-22) and sex chromosomes (X,Y) All body cells have 2 copies of each (2n=2x 23=46:diploid) X,X chromosomes= female X,Y chromosomes= male In body cells (2n), we call the two molecules of a pair homologous chromosomes (Figure 8.11)

o Carry the same genes (except X and Y)o One of the pair contributed via the egg (maternal)o One contributed via the sperm (paternal)

Sex cells have just one molecule of each (n, haploid)o Figure 8.12

Starts with: egg+sperm=zygote Zygote develops by mitosis into adult Adults reproduce gametes from body cells by meiosis and the cycle goes on

Meiosis

Cell division process that makes cells used exclusively for sexual reproductiono Begins with a cell that has the normal amount of DNAo Result in cells with half the DNA of the starting cello Each new sex cell has uniqueDNA

Two key concepts: DNA of original cell must be divided in half DNA of original cell must get mixed up so that the new cell has its own

unique DNA

The basis for sexual reproduction. Two Phases of Meiosis (Figure 8.13)-

Creation of Genetic Variation

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1. Chromosomes assort independentlyo Tetrads line up independently in Meiosis 1o A tetrad could come to the plane and line up in two possible ways

Red-blue or blue-redo There are 8 million (3^23) ways that the chromosomes could line up in Meiosis Io Affect the combination of chromosomes that cells have after Meiosis IIo Figure 8.16

2. Crossing over between tetradso Adjacent sister chromatids exchange geneso Figure 8.18

3. Random Fertilizationo The genetic makeup of any given gamete is 1 of 8 million possibilitieso Which two games that meet is randomo So there are 8 million x 8 million =64 trillion possible genetic combinations resulting

from a single fertilization event

Errors in chromosome distribution during gamete formation- (Figure 8.20)

o Nondisjunction: pair of homologous chromosomes fails to separate(Meiosis I)all have abnormalnumber of chromosomes

o Nondisjunction: pair of sister chromatids fails to separate (Meiosis II) some have ab. Num. ofchromosomes

Sometimes an abnormal gamete is involved in fertilization and results in an abnormal zygote:

Abnormal zygotes usually spontaneously abort long before birth:miscarriage (Figure 8.21)

Chapter 9: Patterns of Inheritance

o What is genetics and who is Gregor Mendel?o What are alleles? What is the role of alleles in expression of a trait?o What kinds of traits follow the most simple pattern of inheritance?o What are the two laws of Mendelian genetics?

Genetics

oThe scientific study ofheredity(the passing oftraits from one generation to the next)(trait is thecombined expression of two copies of the same gene)

o Not all traits are passed on the same wayPatterns of Inheritance

o Gregor Mendel: the father of modern geneticso Growing out many generations of pea plants

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Mendels Pea System

o Easy to control fertilization because plants:o Self-fertilize( self-pollinate)o Cross-fertilize(exchange pollen)

o Starting with true breeding* plants, explored inheritance patterns of several discrete traits: eachwith only two forms: (Figure 9.4)

o *purebred; self-fertilization always produces offspring with traits identical to theparents

Mendels Four Hypotheses

o H1: Genes have alternate versions(alleles), units that determine heritable traitso H2: For each trait of the body, an offspring inherits two alleles, one from each parento H3: if different alleles, most simply, one masks the other when they occur togethero H4: Gamete carry just one allele for a trait because the allele pair segregates during meiosis(Law

of Segregation)

o H1: genes have alternate versions: alleleso Ex. One allele codes for purple, another for white

o H2: for each trait of the body, an offspring inherits two alleles, one from each parento If the same: homozygouso If different: heterozygouso

The two alleles produce a specific trait formo Genotype phenotypeo H3: Alleles occur in two forms; most simpley, one masks the other when they occur

together

Dominant: determines phenotype(notated in uppercase,e.g.,P,A, or D Recessive: no noticeable effect( notated in lowercase, e.g., p, a, or d)

o H4: A gamete carries only one allele because during gene pairs segregate duringmeiosis: the Law of Segregation

Fertilization restores the gene pair:

Final Exam: Wednesday Dec 7, noon

- 35 questions from Chs 9(II), 25/26- 65 questions from all previous chapter

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Chapter 9(II):

What are the two laws of Mendelian genetics?

How do we use knowledge of parent traits to predict traits in offspring of two parents?

Are different traits inherited together?

Two Hypotheses:

- H1: Yes, and so the genes for different traits assort togetherto gametes- H2: No, so gene pairs assort separately, or independently, to gametes

o Actual results support the second hypothesis (Figure 9.8)Mendel tested these using a dihybrid cross:: A cross involving how many traits? 2

o Traits between two parents are the same except for the two traits of interesto Cross two true-breeding parents, homozygous dominant and homozygous recessive

Law of Independent Assortment:

- Allele pairs assort independently of other pairs during gamete formationGenetic Disorders of the Autosomes

Table 9.7

- Most human genetic disorders are recessive.- Heterozygotes express the normal phenotype but carry the recessive allele(carriers) and pass

on to offspring

Sexual Reproduction: Predicting Genetic Outcomes

- Knowing geno- or phenotypes for a trait of each parent, we can calculate the probabilities ofoffspring genotypes

- Genotype probabilities give us phenotype probabilities- Family pedigrees and a Punnett Square are simple tools for determining probabilities

Figure 9.13

Chapter 26: Reproduction and Development

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How do eggs and sperm meet in humans and in other animals? What anatomical structures facilitate sexual reproduction? What are hormones? What organ

o Sexual Reproduction in Animalso New genetically unique individual created by fertilization of an egg by a sperm:

The union of two haploid gametes to create one new diploid offspring (Figure26.12)

o Fertilization can be either: External: aquatic organisms (Figure 26.3) Internal: occurs inside female body; allows reproduction in conditions that may

be unfavorable for gametes; requires complex reproductive anatomy

o Human reproductive Anatomy Both sexes in humans have:

Gonads for a) hormone secretion and b) gameotogenesiso Lets talk about hormones for a second.

o What are hormones? Regulatory chemicals that transmit messages between organs inthe body

o Govern metabolic rate, growth, maturation, and reproductiono Made by the endocrine system/ transported by the circulatory systemo Hormone is a signal that prompts a response in target cells only (Figure 25.1)o Hormone production can be disrupted by endocrine disorders (ex. Diabetes)

o Endocrine systemo A dozen major organs, including:

Hypothalamus Pituitary Thyroid Pancreas gonads Figure 25.4)

o Hypothalamus and pituitary Part of the the brain that controls the endocrine system Responds to information from the nervous system Sends out responses via the two parts of the pituitary: (Figure 25.5)

oSex Hormones

Steroid hormones manage sexual reproduction, including gamete formation: Testosterone

o Develops, maintains male reproductive system Estrogen

o Promotes female trait development; maintains femalereproductive system

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Progesteroneo Prepares, maintains the uterus for pregnancy

o Gametogenesis The production of gametes in the gonads

In females: oogenesiso In the ovaries, occurs once every 28 days

In males: spermatogenesiso In the testes, ongoing

o Males: Spermatogenesis (Figure 26.8)o The ongoing process of meiosiso Occurs in the seminiferous tubules of the testeso Haploid cells mature into sperm, streamlined in shape to swim (Figure 26.12)

o Females: Oogenesiso Ovaries contain all follicles at birtho Each follicle holds a primary oocyte (2n cell paused in meiosis I)o Once a month, hormones prompt ovulation:

Development and release of secondary oocyte (paused in meiosis II) Secondary oocyte completes meiosis only if fertilized-whats left is the corpus

luteum

o Human Reproductive Anatomyo Both sexes in humans have:

o Gonads for hormone secretion and gamete productiono Ducts to store and deliver the gameteso Structures to facilitate the meeting of the gameteso Male Reproductive Anatomy: (Figure 26.5)o Female Reproductive Anatomy: (Figure 26.6)

Ovulation: once about every 28 days, a follicle matures and releases an eggo Female Reproductive Cycle

o Repeats about once a month (varies from 20 to 40 days)o A recurring sequence of two cycles:

The ovarian cycle: controls growth and release of the oocyte, varies in length The menstrual cycle: prepares the uterus for possible implantation, 14 days long

Hormones coordinate the cycleso Hormones

Ovarian cycle(varies in length):

Estrogen signals the hypothalamus to tell the anterior pituitary tosecrete FSH, LH

Follicle stimulating hormone (FSH) prompts follicle development; thefollicle itself secretes increasing amounts of LH and estrogen

Luteinizing Hormone (LH) peaks and triggers ovulation The corpus luteum( follicle remnant) degrades over time until it is gone

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The Menstrual Cycle(14 days long)o Follicle remnant secretes progesterone, which inhibits FSH and

LH and promotes thickening of the endometrium

o Once the follicle remnant is gone, so is the progesteroneo HCG and Pregnancy

Hormone targets the corpus luteum Progesterone and estrogen maintained Endometrium not shed

Secretion of HCG promotes pregnancy: carrying developing young in the uterus In humans, pregnancy is 40 weeks from day 1 of the last menstrual cycle

Divided into trimesters