IB Biology HL Yr 1 Midterm Study Guide PDF Form

Melanie Maldonado Sunday, February 1, 2015

IB Biology HL Yr 1 Midterm Study Guide

Unit 2: Evolution — Darwin’s Theory of Evolution - Populations have massive reproductive potential

- Population sizes are stable

- Individuals compete to survive

- Resources are limited

- Variations exist between individuals

- A lot of variations are heritable

- Only most fit individuals survive

- Evolution occurs as most advantageous traits pile up

Gene Pools - Definition: the combined genetic information of all the members of a particular

population.

- relative frequency of an allele is the number of times that allele occurs in a gene pool compared with the number of times other alleles occur

Sources of Genetic Variation - 1. Mutations

- are any change in a sequence of DNA

- can occur because of mistakes in the replication of DNA, or as a result of radiation or chemicals in the environment

- can be limited to one of a few bases of DNA, or they can affect lengthy segments of chromosomes

- do not always affect phenotype (physical, behavioral, and biochemical characteristics)

Melanie Maldonado Sunday, February 1, 2015- 2. Gene Shuffling

- occurs during production of gametes

- crossing over can also occur during meiosis - further increases number of genotypes that can occur in offspring

- recombining of alleles can produce dramatically different phenotypes

- produces many different gene combinations, but does not affect relative frequencies of alleles

Types of Gene Traits: Single Gene - Single Gene Traits: controlled by 1 single gene that has 2 alleles

- How can Natural Selection affect single-gene traits?

It can lead to changes in allele frequencies, and thus to evolution*.

ex. Rock Pocket mouse

NOTE* will only lead to evolution if trait affects fitness.

****************************************************************************************************

- Polygenic Traits: controlled by 2 or more alleles (height, hair color, etc.)

- How can Natural Selection affect polygenic traits?

3 DIFFERENT WAYS

1. Directional Selection

- is when individuals at one end of the curve have more fitness than others. Causes entire curve to shift in one direction as character trait changes— causes increase in number of organisms with the trait at one end of the curve.

- ex. increase in average size of beaks of finches.


2. Stabilizing Selection

- is when individuals near the center of the curve have higher fitness than ones at either end of the curve. Causes curves ends to come more towards middle - increase in number of organisms in middle section.

- ex. the weight of infants when born - ones that are larger/smaller than usual are less likely to live

3.Disruptive Selection

-is when individuals at the upper and lower ends of the curve have more fitness than those in the middle. Natural selection acts strongly against those of intermediate type

-ex. medium-sized seeds become less common, so birds with smaller or larger beaks have more fitness


Genetic Drift - in small populations, individuals that carry a particular allele may leave more

descendants than other individuals, just by chance.

- Over time, a series of chance occurrences of this type can cause an allele to become common in a population.

- Founder Effect - Allele frequencies change as a result of the migration of a small subgroup of a population

Genetic Equilibrium - when allele frequencies remain constant

- Hardy-Weinberg Principle states that allele frequencies in a population will remain constant unless one or more factors cause frequencies to change

Conditions to maintain Genetic Equilibrium are:

A. There must be random mating

B. Population must be very large

C. No movement in or out of population

D. No mutations

E. No natural selection

GENETIC EQUILIBRIUM = NO EVOLUTION

The Process of Speciation - Speciation is defined as the formation of a new

species

- Speciation is a result of reproductive isolation— when the members of two populations cannot interbreed.

- Two types of speciation, ALLOPATRIC SPECIATION (speciation due to a geographic barrier) and SYMPATRIC SPECIATION (speciation due to a non-geographic barrier)


There are two types of reproductive isolations- PREZYGOTIC ISOLATION MECHANISMS and POST-ZYGOTIC ISOLATION MECHANISMS

Prezygotic isolation mechanisms prevent the formation of viable zygotes.

Types of are…

A. Behavioral Isolation

- occurs when two populations are capable of interbreeding but have differences in courtship rituals (breeding calls, mating dances, etc.) or other types of behavior

- ex. birds whose habitats overlap, but use different songs to attract mates

B.Geographic Isolation

-occurs when two populations are separated by geographic barriers such as rivers, mountains or bodies of water

-ex. squirrels who are separated from rest of population by river, so two separate gene pools form

C. Temporal Isolation

- occurs when two populations whose ranges overlap but have different periods of sexual activity or breeding seasons

- ex. one frog having a breeding season from January to March, but another frog having a breeding season from March to May

Melanie Maldonado Sunday, February 1, 2015D.Mechanical Isolation

-occurs when physical differences prevent mating/pollination from occurring

-ex. in a snail species, direction of shell coiling is controlled by a single gene. if a snail has a left-coiling shell, it cannot mate with those who have a right-coiling shell

E. Gametic Isolation

- occurs when gametes are chemically (genetically) incompatible, and will not fuse to form a zygote

- ex. some sea urchins have overlapping ranges of population, but their gametes are incompatible

F.Ecological Isolation

-occurs when geographic ranges of two species overlap, but their ecological needs or breeding requirements differ enough to cause reproductive isolation

-ex. one type of frog breeding in permanent ponds, and one type of frog breeding in moving streams

Melanie Maldonado Sunday, February 1, 2015Postzygotic isolation mechanisms prevent hybrids from passing on their genes.

Types of post-zygotic isolation mechanisms are…

A. Hybrid Inviability

- occurs when a zygote may form with the union of egg and sperm, but embryo dies after a few cell divisions. Genetic information from male and female parents is insufficient enough to carry organism through morphogenesis

B. Hybrid Sterility

- occurs when a hybrid is produced, but is unable to reproduce due to meiotic problems

C. Hybrid Breakdown

- occurs when successive generations of hybrids suffer greatly lowered fertility, which eventually leads to being selected out of population

Evidence of Evolution

6 DIFFERENT TYPES OF EVIDENCES OF EVOLUTION

I. Fossil Record

II. Biogeography

III. Comparative Embryology

IV. Homologous Structures

V. Analogous Structures

VI. Genetics

Melanie Maldonado Sunday, February 1, 2015I. Fossil Record

- fossils are remains of ancient life and different layers of rock that had been formed at different times in Earth’s history

- by examining fossils from sequential layers of rock, one could view how a species had changed and produced different species over time

- ex. fossils of the first tetrapods (four-legged creatures)

II. Biogeography

-is the distribution of living species

-species now living on different continents, had each descended from different ancestors

-because some animals on different continents were living under similar ecological conditions, they were exposed to similar pressures of natural selection -> animals ended up evolving certain striking features in common

III. Comparative Embryology

- embryos are organisms in early development

- in early stages of embryo development, they are all strikingly similar

- it is clear that the same groups of embryonic cells develop in the same order and in similar patterns to produce the tissues and organs of all vertebrates

Melanie Maldonado Sunday, February 1, 2015IV. Homologous Structures

-similarities among vertebrates body parts

-homologous structures are mature structures that serve different functions but develop from the same embryonic tissues

-provide evidence that all four-limbed animals with backbones have descended from common ancestors

V. Analogous Structures

- analogous structures are mature structures that have different structure but serve the same purpose

- structures seemed to have evolved from under natural selection in similar environments

VI. Genetics

-evolution in genetics is evident in DNA codes

-organisms with similar genetic coding are more closely related, as organisms with less similar genetic coding are more distantly related

-allows mapping of relationships between organisms, evidence of common ancestors

Sunday, February 1, 2015

Unit 2: Evolution ***NECESSARY TO KNOW1. Compare analogous structures and homologous structures and give an example of each…- Homologous structures have different appearances, but have similar underlying

structure. They also have different functions. An example is a human hand and a whale flipper. However, analogous structures have similar appearances, but have different underlying structure. Analogous structures usually have similar functions. An example is the wings of a bat and a bird.

2. List and describe two examples of natural selection (one must be antibiotic resistance)…- Antibiotic resistance is when antibiotics are used incorrectly and result in adapted

bacteria. When you use antibiotics, there are certain bacteria that have more resistance to them than others. If you do not follow your antibiotic regimen properly, and discontinue use before you should just because you no longer feel the effects, the most resistant bacteria linger in your body and continually reproduce, passing their resistance on to their offspring. These resistant bacteria have been produced as a result of natural selection.

- Peppered moths were present in their respective environment prior to the time of industrialization. Before industrialization and all of the pollution it left in the environment, the light peppered moth was more common than the dark peppered moth. This was due to the fact that the light peppered moth blended in with the environment more well and could avoid predators. However, once the environment became polluted and darker, the dark peppered moth phenotype became much more frequent because the environmental factors that make moths with the dark phenotype more fit.

Unit 3: Genetic Evolution —- ***NECESSARY TO KNOW

1. Explain transient and balanced polymorphism using an example for each.

- Transient polymorphism is when one allele slowly replaced by another allele, and becomes much more frequent. An example of transient polymorphism is the peppered moth— prior to industrialization, the light peppered moth phenotype was much more frequent than the dark phenotype due to the fact that they have an easier time blending in with the environment to avoid predators. Once pollution occurred, and the dark phenotype moth began to have ease blending in with the environment, the dark phenotype progressively replaced the light phenotype.

- Balanced polymorphism is when alleles are in equilibrium with eachother, and the two alleles together give you an advantage. An example of balanced polymorphism is sickle cell anemia. When a human possesses both alleles (one allele makes you prone to malaria but also gives you normal blood function, and the other allele makes you prone to sickle-cell anemia but immune to malaria, but sickle-cell allele is recessive,) they are put at an advantage compared to those who possess homozygous alleles.

Sunday, February 1, 20152. Compare allopatric speciation and sympatric speciation, giving an example for each.

- Allopatric speciation is when the formation of a new species occurs due to a geographic barrier. An example of this is two populations of squirrels not being able to interbreed due to a river that lies in between the separate populations. This leads to separate gene pools, and eventually speciation.

- Sympatric speciation is when the formation of a new species occurs due to a non-geographic barrier. An example of this is a temporal barrier. A temporal barrier exists between two species when they have different mating/breeding seasons during the year. An example of a temporal barrier existing between organisms is when one type of frog has a mating season from January to March, and then a similar type of frog has a mating season from March to May. Since these populations do not interbreed, it will likely lead to speciation.

3. Describe the two paces of evolution (Punctuated Equilibrium and Gradualism)

- One pace of evolution is called punctuated equilibrium. Punctuated equilibrium is the idea that evolution does not occur steadily over time, but only rapidly when environmental factors make it necessary. There are long periods of no change followed by brief periods of rapid evolution.

- Another pace of evolution is called gradualism. Gradualism is the theory that evolution occurs consistently, but gradually. Then, the adaptations that accumulate over time lead to evolution.

Unit 4: Classification — Cladograms - Cladograms are the representation of evolution over time in a diagram that shows…

• what organisms are more closely related than others

• what adaptation/change occurred that brought about evolution

• the presence of a common ancestor

• distinctive features that separate one organism/group of organisms from other organisms


Animal Phyla

There are 6 different animal phyla we must know for our test.

A. Porifera

- only sponges

- no body tissue, no symmetry, no coelm, no segmentation, no entrance

- ex. Sponge

B.Cnidaria

-some possess stinging cells

-true tissue, radial symmetry, no coelm, no segmentation, 1 entrance

-ex. sea anemone, corals, jellyfish, etc.

C. Platyhelminthes

- true tissue, 3 body layers, bilateral symmetry, no coelm, no segmentation, 1 entrance

- flattened free-living worms

- ex. tapeworm

Sunday, February 1, 2015D. Annelida

- true tissue, 3 body layers, bilateral symmetry, coelm, segmentation, 2 entrances

- ex. earthworm

E.Mollusca

-true tissue, 3 body layers, bilateral symmetry, coelm, no segmentation, 2 entrances

-also possess a foot (visceral muscle mass) and sometimes shell

-ex. snails

F. Arthoropoda

- true tissue, 3 tissue layers, bilateral symmetry, coelm, segmentation, 2 entrances

- jointed appendages, exoskeleton

- ex. spiders, crustaceans

G. Chordata

- true tissue, 3 body layers, bilateral symmetry, coelm, no segmentation, 2 entrances

- includes all vertebrates

- ex. fish


Plantae Phyla

A. Bryophytes

- Leaves, Roots & Stems: no true leaves or roots

- Reproductive Features: spores produced

- Other Features: anchored by rhizoids

- ex. moss

B. Filicinophytes

- Leaves, Roots & Stems: have leaves, roots and non-woody stems

- Reproductive Features: spores in sporangia on underside of leaf

- Other Features: have large leaves that are divided into leaflets (tiny leaves)

- ex. ferns

C. Angiosperm

- Leaves, Roots & Stems: have leaves, roots and stems (woody and non-woody vary)

- Reproductive Features: seeds found in fruits produced

- Other Features: have flowers

- ex. sunflower

D. Conifer

- Leaves, Roots & Stems: have leaves, roots and woody stems

- Reproductive Features: seeds found within cones produced

- Other Features: leaves are usually narrow with a thick, waxy cuticle

- ex. cones and pines


Binomial Nomenclature, Problems w/ Definition of Species & Hierarchy ***ALL NECESSARY INFORMATION• Binomial Nomenclature is the 2 word international naming system invented by

Linnaeus. Each species is given 2 names, The first is the genus name with a uppercase letter, and the second is the species name with a lowercase letter.

- appears as Genus species

Kingdom, Phylum, Class, Order, Family, Genus, Species

What is the problem with the definition of species?

- Many sibling species have been found. These are species that cannot interbreed, but show no significant differences in appearance. They are separate species, but are very difficult for ecologists to identify. (ex: the Pipistrelle Bat in Britain was recently shown to be two sibling species)

- - Some pairs of species that are clearly different in their characteristics will interbreed. Many plant species hybridize and some animals also. (ex: ruddy ducks and white-headed ducks).

- - Some species will always reproduce asexually, so the members of a population do not interbreed. The biological definition therefore does not apply.

Unit 5: Basic Chem & Water The most frequently occurring chemical elements in living things are carbon, hydrogen, oxygen and nitrogen. Other common elements that are necessary for survival are sulfur, calcium, phosphorus, iron and sodium.

Organic molecules are molecules composed of only carbon and hydrogen.

- Carbon: necessary component of organic molecules, required to build proteins, carbohydrates and fats

- Hydrogen: necessary component of organic molecules, found in water which makes up majority of body

- Oxygen: required for cellular (aerobic) respiration which is necessary for life

- Nitrogen: vital component of amino acids and nucleic acids, the building blocks for proteins and DNA

Sunday, February 1, 2015- Sulfur: a part of some amino acids, involved in protein synthesis of amino acids

- Phosphorus: a phosphate base is a component of DNA, also part of ATP (energy)

- Iron: found in blood, which is used to circulate oxygen throughout the body

- Calcium: Regulates production of cell wall in plants, strengthens bones, muscle contraction

ORGANIC MOLECULES: Molecules made up of carbon & hydrogen only.

NON-ORGANIC MOLECULES: Anything that does not fall under organic

Hydrogen Bonding, Properties of Water and how it is necessary for life ***ALL NECESSARY INFORMATION

• Explain and draw hydrogen bonding in water molecules

Hydrogen bonding occurs between water molecules due to the fact that water molecules are polar molecules, which means that they possess partially positive and partially negative ends. These bonds between partially positive and negative ends are weak when there are only few, but when there are many hydrogen bonds are extremely strong. Hydrogen bonding can only occur between Hydrogen, Fluoride, Oxygen and Nitrogen.

• List 3 properties of water and explain those properties.

Some properties of water are its thermal, cohesive and solvent properties. Thermal properties of water include heat capacity, boiling and freezing points and the cooling effect of evaporation. Water has a large heat capacity which means that a considerable amount of energy is needed to increase it’s temperature. This is due to the strength of the hydrogen bonds which are not easily broken. Water has a high boiling and freezing point. It boils at 100 C because the strong hydrogen bonds. All these hydrogen bonds between the water molecules need to break for the liquid to change to gas. Cohesion is the effect of hydrogen bonds holding the water molecules together. Water moves up plants because of cohesion. Long columns of water can be sucked up from roots to leaves without the columns breaking. The hydrogen bonds

Sunday, February 1, 2015keep the water molecules sticking to each other. The solvent properties of water mean that many different substances can dissolve in it because of its polarity.

• How is water vital for life? Explain while making connection to it’s properties.

The thermal properties make water vital for life due to the fact that it is used to maintain homeostasis. When organisms perspire, the sweat that is released onto the surface of the skin cools down your body temperature in order to maintain bodily functions. The cohesive property of water allows plants to transfer it through the vascular system, as a transport medium for nutrients, or other substances. Water is also important to life because it provides a habitat for aquatic organisms. It’s low freezing point and high boiling point make it a safe habitat due to it’s high heat capacity. Water’s transparency makes it important also because since provides a habitat to aquatic organisms, if it weren’t for water’s transparency, it would be much more difficult to sustain life underwater. It’s transparency also makes it possible for plants to perform photosynthesis underwater.

Unit 6: Biochemistry

Molecule Monomer Polymer Function Image

Carbohydrate Monosaccharide, glucose, simple sugar

Polysaccharide, starch, glycogen

Energy source, raw materials for molecules

Protein Amino acids Polypeptides, protein

Determined by structure, catalyst

Lipid Fatty acids, glycerol

Phospholipid, triglyceride

Nutrition, storage, insulation

Nucleic Acid Nucleotide DNA, RNA, Nucleic Acid

Storage of genetic information


Carbohydrates

STRUCTURES OF CARBOHYDRATES TO KNOW

1.Monosaccharide (consist of a single monomer)

-forms of monosaccharides are glucose, ribose, fructose, galactose, deoxyribose, simple sugars, etc.

-ring is composed of multiple carbons and one oxygen atom

-ex. glucose (image)

2. Disaccharide (consist of 2 monomers)

- pairs of monosaccharides linked together by dehydration synthesis

- have a distinct double-ring structure

- ex. maltose, lactose & sucrose (images)

3.Polysaccharide (multiple monomers to form a polymer)

-many monomers brought together form a polysaccharide

-some have a branched structure

-costs little energy to build, releases energy when digested

-ex. cellulose, starch, glycogen (images)


Carbohydrates: What to Know

II. Give 3 examples of monosaccharides, disaccharides, and polysaccharides.

Three types of monosaccharides are glucose, ribose and deoxyribose. Three types of disaccharides are fructose, sucrose and maltose. Three types of polysaccharides are starch, glycogen and cellulose.

III. Be able to identify glucose and ribose from diagrams.

- A glucose molecule has a hexagon structure. A ribose molecule has a pentagon structure.

IV. State one function of glucose, glycogen and lactose in animals.

- A function of glucose in animals is that it’s used as an energy source for the body.

- A function of glycogen in animals is that it’s a source of long-term energy storage, and is stored primarily in muscles and in the liver.

- A function of lactose in animals is that it’s the sugar found in milk that is given to newborns.

V. State functions of sucrose, fructose and cellulose in plants.

- A function of sucrose in plants is that it’s used as an energy source for the plant.

- A function of fructose in plants is that it’s found in fruit, and gives sweetness to attract animals.

- A function of cellulose in plants is that it makes up the cell wall.

I. State functions of carbohydrates.

- Raw materials, energy, energy storage and creating structural compounds


Proteins - proteins are long chains of polypeptides, which are

formed from amino acids (protein’s respective monomer)

- look for nitrogen when identifying proteins

- functions of amino acids are protein synthesis, energy reserve and hormones (thyroxin) - form fits function

- bonds between amino acids are called peptide bonds (another form of covalent bonds) that are formed by nitrogen and carbon

- polar amino acids are hydrophilic (does not repel water) and tend to be placed on the outside of the protein

- non-polar amino acids are hydrophobic (repels water) and tend to be placed on the inside of the protein

Proteins: Structures

I. Primary Structure

- this structure determines the folding of the polypeptide to give a functional protein

II. Secondary Structure

- folding of the nitrogen-carbon-carbon backbone of the polypeptide chain using weak hydrogen bonds

- produces alpha helix and beta pleating

III. Tertiary Structure

- folding of polypeptide into domains whose chemical properties are determined by the amino acids in chain

- folding is sometimes held together by strong covalent bonds

IV. Quaternary Structure (not all proteins reach this structure)

- some proteins are made of several polypeptide subunits — these subunits fit together to form a functional protein


Proteins: Functions

There are many different functions that proteins possess. Ones I need to know are…

A.Catalytic - act as a catalyst in order to speed up chemical reactions. ex. rubisco: acts as an enzyme in photosynthesis

B.Storage - biological reserves of metal ions and amino acids. ex. casein: found in milk

C. Transport - transports nutrients, other materials, etc. ex. hemoglobin: blood cells, transport oxygen throughout body

D. Communication - act as notifiers for releasing chemical messages to other structures. ex. insulin: is hormone that regulates blood sugar

E. Contractile - generate force for muscle contraction. ex. myosin: converts chemical energy (ATP) to mechanical energy, which creates force and movement

F. Protective - help protect the body against any problems that may occur. ex. immunoglobin: act as antibodies, attach to pathogens (foreign invaders) and mark them to be destroyed

G. Toxins - may act as toxic substance in order to protect organism. ex. snake venom: is used to protect snake from attackers or to catch prey

H. Structural - are fibrous proteins, involved in structure. ex. collagen: provide elasticity of skin, tendons, and ligaments

I. Pigment - induce colors in skin, eyes, etc. ex. rhodospin: makes rod cells of retina light-sensitive


Lipids - lipids are hydrophobic (“water fearing.) They will not mix with water and will repel it.

- includes fats, waxes, steroids and oils

- the cell membrane is composed of lipids called phospholipids, have a head that is hydrophilic, and two tails that are hydrophobic

Lipids: Types

1. Triglycerides

- made up of 3 fatty acids and one glycerol. formed by dehydration synthesis

- fats and oils fall under the triglyceride category

2. Phospholipids

- only have two fatty acids linked to glycerol, and a phosphate group

- only partly hydrophobic, form the basis of membranes

3. Steroids

- four fused rings in their molecule

- ex. cholesterol, progesterone, estrogen, testosterone

Lipids: Function - Serve as energy storage. Fats provide much more energy than carbohydrates do,

but take more energy to access (they are stored away.)

- Provide thermal insulation. Fats help keep the body warm and reduce heat loss.

- Makes up the double-layer of all membranes. Phospholipids are used to make up the cell membrane.

- Buoyancy. Since lipids are less dense than water, it allows buoyancy and animals can float in the water.


Nucleic Acids - Nucleotides are composed of three parts: a pentose sugar (ribose or deoxyribose,)

a phosphate group and a base (Adenine, Guanine, Cytosine, Thymine, or Uracil)

- two types of strands that can form from nucleotides- Deoxyribonucleic Acid (DNA) or Ribonucleic Acid (RNA)

- RNA is one strand of nucleotides, DNA is two strands

- in DNA, strands are antiparallel. Strands are linked by hydrogen bonding between their bases. Complementary base pairs are Adenine-Thymine and Cytosine-Guanine. in RNA, complementary bases are the same except Cytosine is paired with Uracil. Covalent bonds form between the phosphate groups and the sugars.

- DNA serves as genetic coding for genes, and a blueprint for building proteins.

- RNA serves as a blueprint for new cells, the next generation.

- Phosphorus and Sulfur serve as backbone for DNA

- there are two types of nucleotides…

1. Purines

• double ring nitrogen base, includes Adenine and Guanine. Adenine and Guanine are larger in size than Cytosine, Uracil and Thymine (Pyrimidines.)

• 2 hydrogen bonds are formed between Adenine and Thymine.

2. Pyrimidines

• single ring nitrogen base, includes Cytosine, Uracil and Thymine. Cytosine, Uracil and Thymine are smaller in size than Adenine and Guanine (Purines.)

• 3 hydrogen bonds are formed between Cytosine and Guanine/Uracil.


DNA Strand Pairing, Carbohydrates vs. Lipids, the role of Dehydration Synthesis and Hydrolysis, ***ALL NECESSARYI. Describe the structure of DNA, including the antiparallel strands and hydrogen

bonding between pyrimidines and purines.

The double-helix structure of DNA is formed by two anti-parallel strands of DNA. To form one single strand of DNA, covalent bonds must be formed between the phosphate group and sugar of nucleotides to form a strand. Then, to form a double-helix structure, hydrogen bonds are formed between complementary base pairs (Purines-Pyrimidines, A-T, C-G) C-G form 3 hydrogen bonds and A-T form 2 hydrogen bonds.

II. Compare the use of carbohydrates and lipids in energy storage.

Carbohydrates and lipids can both be used as energy storage however carbohydrates are usually used for short term storage whereas lipids are used for long term storage. Carbohydrates are soluble in water unlike lipids. This makes carbohydrates easy to transport around the body (from and to the store). Also, carbohydrates are a lot easier and more rapidly digested so their energy is useful if the body requires energy fast. As for lipids, they are insoluble which makes them more difficult to transport however because they are insoluble, lipids do not have an effect on osmosis which prevents problems within the cells in the body. They also contain more energy per gram than carbohydrates which makes lipids a lighter store compared to a store of carbohydrates equivalent in energy. Carbohydrates are stored as glycogen in animals, and lipids are stored as fats in animals.

III. Outline the roles of dehydration synthesis or hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides—between fatty acids, glycerol and triglycerides— and between amino acids and polypeptides.

In order to create polymers out of monomers, dehydration synthesis must occur. Dehydration synthesis is the formation of bonds that results in excess water molecules. In order to break down polymers into monomers, hydrolysis must occur. Hydrolysis is the process of adding water to polymers, and having bonds between monomers break down. To create bonds between amino acids to form polypeptides, between monosaccharides to form di/polysaccharides, or between monoglycerides to form triglycerides, dehydration synthesis must occur. Hydrolysis (the opposite of dehydration synthesis) is necessary to break down those bonds.


Unit 7: Cells, Intro to Cells and Cell Theory

Cell Theory

1. All living things are composed of cells

2. The cell is the smallest unit of life

3. Cells only can come from pre-existing cells

Evidence for the cell theory comes from microscopes. They offer increased visualization of tiny objects. Things viewed under a microscope have been found to be made of cells. Evidence is also found through Francesco Redi’s study with the meat jars, on the subject of spontaneous generation.

All life performs 7 different life functions.

1. Movement - the ability to move from location to location. The ability to propel blood, nutrients, urine, etc. through the body also counts as movement (sessile organisms.)

2. Reproduction - the ability to produce new cells or other offspring.

3. Responding to the environment - the ability to sense changes in the environment and reacting to them.

4. Metabolism - the ability to break down substances (includes all chemical reactions that occur within cells.) Metabolism is regulated by hormones

5. Growth - the ability to increase in size (number of cells.)

6. Excretion - the ability to remove waste from the organism. Includes the digestive system evaluating feces, urinary system evaluating urine, respiratory system exhaling carbon dioxide, etc.

7. Nutrition - the ability to take in food and substances that is necessary for survival.


Origin of Life on Earth

4 conditions necessary for life to develop on Earth…

- Non-living synthesis of simple organic molecules

- Assembly of organic molecules into polymers

- Origin of self-replicating molecules that make inheritance possible

- Packing of molecules into membranes

Miller & Urey Experiment• Early Earth had high temperatures, lots of meteor showers, lots of lightning storms, many

volcanoes, and most of Earth was ocean.

• Miller & Urey wanted to test to see perhaps how organic molecules were created from inorganic matter on Earth. Their experiment was…

I. In a glass refluxing system, they created a miniature early Earth.II. This early Earth replica included hydrogen, methane, ammonia and water III. The mixture was heated and sparks were used to mimic lightning before allowing the Earth

to cool down.• After performing this experiment and leaving their miniature Earth for a week, they found

that organic molecules were able to be created by things in their Earth. • The conclusion was that organic molecules had first formed in placed such as

volcanoes, hydrothermal vents, or any other location where they could flourish.

Endosymbiotic TheoryEndosymbiotic theory is the theory that chloroplasts and mitochondria formed by a prokaryote being ingested by another cell. Endosymbiotic theory also states that eukaryotic cells are believed to have evolved from aerobic prokaryotes.Evidence for this theory: • Mitochondria and chloroplasts both have double-membranes (not a normal trait of

organelles)• Mitochondria and chloroplasts both have ribosomes within them—similar to prokaryotes• Mitochondria and chloroplasts are both roughly the same size as bacteria• Mitochondria and chloroplasts both have their own DNA coding.

How is cell size limited by the ratio of surface area:volume?• Smaller cells have a larger ratio than larger cells.• The cell membrane must be large enough to absorb nutrients.• Cells divide when they reach a certain size.• If ratio gets too small, substances won’t be able to enter the cell fast enough to fuel chemical

reactions and waste will accumulate faster than it can be excreted.


Stem Cells & Differentiation

Differentiation is defined as the specialization of a cell. It occurs numerous times during development of multicellular organisms. When a zygote forms, it changes from a simple zygote to a complex system of tissues and cell types— this is all due to differentiation.

An example of differentiation is a zygote changing to a multicellular embryo, then to a more complex system of fetus.

Stem cells are cells that have yet to differentiate, so they are unspecialized and can become any type of cell. They have two qualities-

1. Self Renewal- can continually divide

2. Potency- possess the capability to differentiate

************************************************************Stem Cell UsesThere is many ways that stem cells can be used to treat disease. However, there are certain ethical issues surrounding the use of stem cells due to our duty to respect the value of human life, although we also have a duty to prevent or alleviate suffering.

Need to know two different ways you can use stem cells:

Using stem cells to treat Stargardst’s Disease (disease that affects vision) -1. Stem cell researcher has an embryonic stem cell2. Researcher differentiates that embryonic stem cell into a retinal cell 3. New retinal cell is injected into retina and enters the body4. Retinal cell attaches to patient’s existing retinal cells, which do not function properly5. Once stem cell attaches to retinal cells, they will all slowly improve functional properties6. Result: Vision will begin to improve greatly.Using stem cells to treat Leukemia-1. Stem cell researcher has an embryonic stem cell2. Researcher differentiates that embryonic stem cell into a bone marrow cell (gives rise to red

blood cells, white blood cells, and platelets in the body)3. Chemotherapy has the ability to kill normal cells in bone marrow—leads to patient not being

able to produce blood cells.4. Doctor will inject healthy bone marrow cells into patient5. Injected cells will find way to bone marrow and begin to produce healthy cells6. Result: Allows patient to be able to produce healthy blood cells


Eukaryotic & Prokaryotic Cells

Eukaryotic cells and prokaryotic cells are very differing— eukaryotic cells are cells that are multicellular, and prokaryotic cells are unicellular.

Be able to compare and contrast prokaryotic & eukaryotic cells!• Prokaryotic cells have naked DNA• Prokaryotes do not possess mitochondria, chloroplasts, centrioles, etc. • Prokaryotes reproduce by binary fission.• Prokaryotes have smaller ribosomes— 70s• Prokaryotes either have no or few organelles bounded by a single membrane.• Eukaryotic cells have chromosomes made up of DNA and proteins• Eukaryotic cells include animal cells and plant cells, and can possess all organelles that

P+A cells have• Eukaryotic cells have larger ribosomes—80s • Eukaryotic cells have many organelles• Both prokaryotic cells and eukaryotic cells can have a cell wall, cell membrane, pili,

flagella, ribosomes, and plasma membrane• Both can reproduce

Prokaryotes Eukaryotes

nucelus no, only posses a nucleoid (loose bundle of chromosomes)

yes

membrane-bound organelles no yes (many)

size 1-10 micrometers 10-50 micrometers

when did they evolve 3.5 billion yrs ago 1.5 billion years ago

cytoplasm yes yes

cell membrane yes yes

cell wall some do plants

ribosomes yes yes

DNA circular, free floating DNA chromosomes in nucleus

examples bacteria plants, animals, etc.


Be able to draw and label a diagram of an animal cell!Make sure to label:• Rough endoplasmic reticulum• Cell membrane• Lysosome• Golgi body/apparatus• Nuclear membrane• Nucleus• Mitochondria• Ribosome

Be able to draw and label a diagram of a prokaryotic cell!Make sure to label:• Cell wall• Cell membrane• Pili• Ribosome• Nucleoid• Cytoplasm• FlagellaAnimal Cells & Plant Cells Organelles

organelle plant cell animal cell function

nucleus (and nucleolus)

present present storage of genetic information, manages cell functions

mitochondria not present present performs cellular respiration, converts energy stored in food into energy

lysosome not present present breaks down old organelles, food particles or invading objects

ribosome present present performs protein synthesis

centriole not present present play major part in cell division

cell wall present not present rigid wall made up of cellulose, boundary around cell provides structure and support

organelle


Division of Prokaryotes, Differences between Plant and Animal Cells- Prokaryotes divide by a process called binary fission. It’s an asexual reproduction method,

involving the splitting of the parent organism into separate organisms

(A few) Differences between P & A Cells• Animal cells only have a cell membrane• Plant cells possess a cell membrane and cell wall• Animal cells don’t have chloroplasts• Plant cells don’t have mitochondria or centrioles

vacuole present (much larger) present (much smaller) sac of fluid surrounded by membrane, used for storage of wastes nutrients and water

rough endoplasmic reticulum

present present make large amounts of protein to be exported from cell or inserted to cell membrane

smooth endoplasmic reticulum

present present involved in synthesis of lipids, and breakdown of toxic substances

cytoplasm present present gelatin-like fluid, contains salts, minerals and organic molecules- surrounds organelles

golgi apparatus present present receives and distributes proteins from E.R to organelles or out of cell

cilia & flagella not present present cell mobility

cell membrane present present semi-permeable phospholipid bilayer, controls what enters & exits cell

plastids present not present 3 types: chloroplasts, chromoplasts (synthesize & store pigments,) and leucoplasts (store food such as starches, proteins & lipids

chloroplast present not present photosynthesis

plant cell animal cell functionorganelle


This is the end! Everyone study and make sure you don’t stress too much over the things you don’t understand that well. Good luck everyone :)

Documents

IB Biology HL Yr 1 Midterm Study Guide PDF Form