1. Potential

2. Kinetic

3. Chemical

Capacity to cause change because of where an object is located or how its parts are arranged.

Example: chemical bonds hold atoms in certain arrangements

Energy of motion

Example: muscles that help you bounce

Each conversion, a bit of energy is converted to thermal energy (heat)

*total amount of energy in the universe remains constant

* Energy can undergo conversions from one form to another, but it cannot be created or destroyed

2nd law of thermodynamics

*No energy conversion is ever 100% efficient

*The total amount of energy is flowing from high-energy forms to forms lower in energy

*Whenever energy is transformed to another form, some is converted to heat

ATP

(Adenosine Triphosphate)

*Main energy carriers on cells

*nitrogenous base, sugar (ribose) & 3 phosphate groups

* Endergonic reaction - cell "spends"

* Exergonic reaction - cell "earns"

ADP

(Adenosine diphosphate)

*formed when ATP gives up phosphate group

*nitrogenous base, sugar (ribose) & 2 phosphate groups

AMP

(Adenosine Monophosphate)

*found in RNA

*Nitrogenous base, sugar (ribose) and one phosphate group

*energy in (energy input required)

*cells "spend" ATP (ATP delivers energy to this reaction)

*cells store energy by way of this reaction

*non-spontaneous process that takes place with outside intervention - low energy to high energy

*Energy out (energy released)

*Cells "earn" ATP (ATP accepts energy released by this reaction)

*Ends with net release of energy

*Spontaneous process that takes place with NO outside intervention - high energy to low energy

1) Biosynthetic (anabolic) - endergonic

Example: photosynthesis

2) Degradative (catabolic) - exergonic

Example: aerobic respiration

Anabolic pathway

(Biosynthetic)

*Endergonic -- photosynthesis

*synthesis of larger molecules from smaller ones

From small organic molecules

to

Molecules of life

*reductive process that requires energy

Catabolic Pathway

(Degradative)

*exergonic -- aerobic respiration

*breakdown of larger molecules into smaller ones

From nutrients (carbs, fats, proteins)

to

breakdown products (CO2 and H2O)

*An oxidative process that releases energy

*minimum amount of energy that will get chemical reaction going

*enzymes make energy barriers smaller

*"dynamic bottleneck" or critical point of no return where potentially reacting species convert to products or return to reactants

*Stable reactants must surmount a free-energy barrier to be converted to a product

*This is the barrier

*pockets or crevices where substrates bind & where reactions proceed

*All or part of substrate "fits" this

*Complementary in shape, size, polarity & charge

-hydrogen peroxide enters cavity in catalase (iron molecule)

-A hydrogen is attached to amino acid histidine & oxygen binds to iron

-this binding destabilizes peroxide bonds, which breaks

-H2O forms

-later reaction, another hydrogen peroxide will pull oxygen from iron & then catalase can work again

Atoms or molecules other than proteins that associate with enzymes and are necessary for their function

Metal ions - copper, iron, zinc, calcium & magnesium

Cosubstrates - are only transiently associated with enzyme NAD+ and NADP+

Prosthetic groups - are permanently associated with the enzyme

organic cofactors

NAD, NADP & FAD

Accepts electrons & hydrogen ions

Transfers them within cell

Derived from vitamins

pH

Salinity

Temperature

Hormones

Coenzymes & Cofactors

Allosteric regulators

Difference in number per unit volume of molecules (or ions) of a substance between two adjacent regions

In the absence of other forces, a substance moves from a region where it is more concentrated to one where its less concentrated

"down" the gradient

Steeper concentration gradient

 higher temperatures

 size of molecule diffusing

 Electrical or pressure gradients

Control mechanism

an activity causes a condition to change, then the change itself stops the activity

A cellular change, caused by a specific activity, shuts down the activity that brought it about

Structure Level

Coiling/folding of amino acid chain (polypeptide)

name of mutated proto-oncogene

P53 oncogene inhibits production of normal tumor suppressor protein

Result = unregulated cell growth not halted & results in cancerous growth

Activates cell division

means it codes for a protein that regulates cell growth

Specifically it codes for a tumor suppressor protein which protects from tumor growth

1. DNA cannot leave the nucleus

2. Ribosomes are located outside the nucleus

Structure Level

2 or more polypeptide chains (amino acids chains) form protein

Result from mutation of gene P53 on Chromosome 17

Mutated gene leads to a predisposition toward certain types of cancers

Example of proto-oncogene

Structure Level

Further folds amino chain to 3-D shape

negatively charged R group pull toward positively charged R group and pushes aways from negatively charged R group

hydrophilic - polar, charged - moves to outside

hydrophobic - nonpolar - moves to inside

Albinism

Tay Sachs

Cystic Fibrosis

Sickle-Celled Anemia

Huntington's Disease - in Chromosome 4, HH or Hh will get the disease - lose muscle control, convulsions, nervous degeneration causing death

Polydactyly - Extra toes & finger

Roman Numerals = generations

Squares = males

Circles = females

Shaded/darken = condition that is being studied

Unshaded = individuals that have the dominant phenotype and at least on dominant allele.

Symbols with lines = carriers

A dominant condition is transmitted in unbroken descent from each generation to the next.

Most matings will be the form Mm x mm (Heterozygous or Homozygous) recessive

50% for each child to receive mutated gene & be affected

recessive trait that will only manifest itself when homozygous

Severe conditions: unlikely to live so most matings bw two heterozygous carriers

1/4 chance each child will be affected

the chance that both maternal and paternal alleles at one locus are identical by descent

or

The proportion of all individual's genes that are homozygous bc of identity by common descent

every individual who carries the dominant allele manifests the trait & has at least one affected parent

trait appears in each generation (easy to identify)

appears equally in males & females

Both sexes transmit the trait to their offspring

Does not skip generations

unaffected persons do not transmit the trait

Affected persons have at least one affected parent

appears only when a person inherits 2 alleles

Appear to skip generations

2 affected individuals are offspring of relatives

Appears in both sexes with equal frequency

Trait tends to skip generation

Affected offspring usually born to unaffected parents

Appears more frequently among children of consanguine marriages

Adhesion

Communication

Receptor

Recognition

Phospholipid bilayer is a fluid matrix

Bilayer is two-dimensional solvent

Lipids & proteins can undergo rotational and lateral movement

are asymmetric

Phospholipids

Proteins

Glycolipids

Sterols

Plasma membrane is a mosaic of:

Net movement of like molecules or ions down a concentration gradient

Although molecules collide randomly, the net movement is away from the place with the most collisions (down gradient)

transport occurs through simple diffusion where the rate of diffusion depends on the concentration gradient and the substances solubility in the membrane's nonpolar core

water, O₂ and steroids diffuse readily

Passive transport

Active Transport

Membrane crossing mechanism (Mediated Transport)

Tranporter protein must be activated - ATP gives up phosphate to activate transporter

(think of transporter as locked gate and ATP is the key)

Needs additonal energy input

Membrane crossing mechanism (mediated transport)

Doesn't require additional energy input

Flows down the concentration gradient (high to low)

Allows solutes to move both directions

Endocytosis

Exocytosis

Membrane Crossing Mechanism (Bulk Transport)

Patch of plasma membrane sinks inward and seals back on itself

Allows things in

Membrane Crossing Mechanism (Bulk Transport)

Cytoplasm fuses with plasma membrane so its contents are dumped out

Expels things out

Pressure applied to solution to prevent influx of water

Also called hydrostatic pressure

Diffusion of water across a selectively permeable membrane

H₂O diffuses higher to lower concentration

Side with most solutes has lowest water concentration

Type of diffusion of solutes through membrane (selective diffusion)

Allows diffusion of low-molecule-weight solutes (crystalloids)

Prevents diffusion of high-molecule-weight solutes (macro-molecules)

low-molecular-weight solutes removed by placing pure solvent outside membrane

1. Glucose

2. Cl-bicarbonate exchanger

1. Na/K pump (sodium-potassium pump)

2. ABC Transporters

Active Transport

ATP-dependent multidrug transporter

pumps drugs out of cells

1st stage - light-dependent reaction

2nd stage - light-independent reaction

Glucose

(Passive Transport)

Glucose binds to transporter

Bound glucose makes protein change shape & closes behind glucose

Glucose exposed to inside and detaches from transporter

Transporter is vacant and protein regains its shape

Na/K pump

(sodium-potassium pump)

Active Transport

ATP hydrolysis drives Na out and K in

Antiport - 3 positive charges exit for every 2 that enter

set of techniques for taking one or more genes from one organism and inserting it/them into the genome of another organism.

Often referred to as genetic engineering

1 - cut out specific sequence of DNA (gene of interest) from donor organism

2 - insert gene of interest into DNA of recipient organism

enzyme that cuts DNA into small fragments

example: PvuII - only cuts mutated DNA

1. plasmids - small sort-of-circular pieces of DNA

2. viruses

(Gene placed inside and recipient organism exposed to them)

In plasmid, pUC18, gene bla contains DNA code to make this enzyme

enzyme makes cells resistant to the antibotic ampicillin

enzyme found in luminescence gene called lux that is in bacteria named Photobacterium fischeri

enzyme needed for a checmical reaction that produces light

normally found in organs of certain plankton, fish and squid (allows them to glow in the dark)

Metabolism, reproduction, growth & cellular organization

also: movement, excretion, sensitivity (response to stimulus), respiration & nutrition

POTENTIAL to carry out life processes

Makes their own food

example: plants

All of the various species living

(all populations of all species in specified area)

1. Bacteria - single-celled, no nucleus, prokaryotic

2. Archaea - single-celled, no nucleus, prokaryotic

3. Eukarya - multi-celled, has nucleus, eukaryotic

When hypothesis has been repeatedly & rigorously tested & supported

Successful hypothesis

1. observe event

2 make prediction (develop hypothesis)

3. test prediction

4. observe results

5. revise hypothesis

6. repeat as needed

often in form of statement

 often expressed negatively

 sometimes crude attempts to offer possible explaination for observations

 testable predictions

Single-celled organism

no nucleus or organelles

Achaea & Bacteria

multi-celled organism

DNA inside nucleus

Plants, animals, protists & fungi

Depend on energy stored in tissues of producers

humans, animals

Number of protons in nucleus of atom of given element

# of protons = # of electrons

negative subatomic particle

particles that occupy orbitals around atomic nucleus

repel each other

Mass Number

(Atomic Weight)

Represents # of protons & # of neutrons

Isotopes: vary in mass#

positively charged subatomic particle in nucleus of all atoms

It's number defines element

Chemical bond

 Strong mutual attraction between ions with opposite charged

 If loses electron - positively charged -- If gains electron - negatively charged

bond in table salt (NaCl)

Molecule held together by polar covalent bond & has no net charge

Interaction between covalently bonded hydrogen atom in donor group & a pair of non-covalently electrons on an acceptor group

2 atoms share pair of electrons to fill outermost shell

Non-polar - share electrons equally

Polar - don't share electrons equally

2 molecules covalently bond into a larger one

forms polymers from subunits

enzymes remove -OH from one molecule, H from another and form bond between two molecules (O)

1. Polarity - Partial charged poles

2. Temperature-Stabilizing - Takes alot of heat to break hydrogen bonds

3. Solvent - dissolves many things

4. Cohesion - resists breaking apart (surface tension)

0 to 14

0 = most acidic; highest H+

14 = Most basic; lowest H+

7 = Neutral

Functional Group

-OH

Hydrophilic

In sugars and amino acids

1. hydroxyl

2. methyl

3. carbonyl

4. carboxyl

5. amino

6. phosphate

Carbon has 6 electrons

1st shell = 2 electrons  2nd shell = 8 electrons

3rd shell = 8 electrons

Can form up to 4 covalent bonds

Can form chains or rings

Functional Group (-COH)   --  hydrophilic

In sugars, amino acids & nucleotides

Aldehyde - has 1 hydrogen and 1 R group

at end of carbon backbone (glucose)

Ketone - No hydrogen, 2 R groups

in middle of carbon backbone (fructose)

Functional Group

hydrophobic

In fatty acid chains

functional group

In amino acids, fatty acids, carbohydrates

highly polar

Acts as acid (releases H+)

Simplest Carbohydrates

Glucose & Fructose (Sweet tasting)

Hydrophilic

any molecule of carbon, hydrogen & oxygen

Must have at least 3 carbons

Monosaccharides (simplest sugars)

Oligosaccharides (few sugars)

Disaccharides (2 monosacchrides formed)

Polysaccharides (many sugars)

functional group  -- hydrophilic

In nucleotides (ATP, RNA, DNA), many proteins & phospholipids

Acidic

many sugars

straight or branched chains

Cellulose - cell wall of plants

starch - storage in plants

glycogen - storage in animals

chitin - hard exoskelton (contain nitrogen)

1. Autosomes

2. Sex Chromosomes

non-sex chromosome that are same length, shape and have the same centromere location - carry the same genes for both male and female

paired chromosomes that are different size and related to the sex of the organism

XX = Female    XY = Male

X and Y chromosomes function as homologues during meiosis

2 copies of X chromosomes (XX)

Each X chromosome inherited from each parent

Homozygous

Have 1 X chromosome & 1 Y chromosome

X inherited from mother - Y inherited from father

Because 1 X chromosome, any recessive alleles carried will be expressed

Hemizygous

Fewer than 2 dozen genes identified  --

Carries 307 genes

SRY gene is master gene for sex determination - forms in the testes

Band located at top of chromatid

(if band absent, then SRY gene absent and will not be male)

Carries approx. 2000 genes (1336 genes)

Most genes with nonsexual traits

can be expressed in both males & females

Doesn't have SRY gene

(due to absence, forms the ovaries instead of the testes)

- arrested cells are broken apart

-metaphase chromosomes are fixed & stained

-chromosomes are photographed through microscope

-photograph of chromosomes is cut up and arranged to form karyotype diagram

A pair or set of genes on a chromosome that tend to be transmitted together

Genes on one type of chromosome

unequal ratios of 4 types of gametes

most gametes have parental genotypes

A smaller number have recombinant genotypes

- fundamental building blocks of all substances, living and nonliving

-smallest particles that retain properties of an element

- made up of subatomic particles

tough, indigestible, structural material in cell wall of plants

polysaccharide

polysaccharide

easily digested, storage form in plants

-sugar storage form in animals

-stored in muscle & liver cells

-when blood sugar decreases the liver cells degrade and release glucose

-looks like a bush

structural material for hard parts of invertebrates

contains nitrogen

Contains digestive enzymes to help break food down

digests, recycles materials

makes, process & packages proteins & lipids

1. nuclear envelope

2. nucleoplasm

3. nucleolus

4. chromatin

1. microtubules

2. microfilaments

3. intermediate filament

synthesis of lipids

makes lipids, degrades fats, inactivates toxins

1. tight junction

2. adhering junction

3. gap junction

Long, slender cellular structure used for mobility

Eukaryotes - whips side to side

Prokaryotes - rotates like propeller

A protein filament that projects from the surface of some bacterial cells

used to cling to surface or move across surfaces

energy powerhouse, produces many ATP by aerobic respiration

makes energy out of food

1. bacterial flagellum

2. plasma membrane

3. pilus

4. DNA in nucleoid region

5. cytoplasm with ribosomes

What are 5 components of prokaryotic cell?

-single bonds between carbons

-chains straight so pack tightly

- short chains = softer fats

-long chains = harder fats

-has carboxyl group at end (-COOH)

-saturated and non-saturated fatty acids

-symbol of each element is abbreviation of its name

-elements ordered by atomic number

Functional group  --  hydrophilic

In amino acids and certain nucleotides

Acts as weak base (accepts H+)

perform 3 biological functions: form bilayer of membrane, store energy and signal between cells

consists of fatty acids, tricyglycerols, glycerophospholipids, sphingolipids, steriods and waxes

-has one or more double bonds

-chains kinked or bend so pack less orderly

-short chains = harder fates

-long chains = softer fats

-energy reservoirs in animals

-allows starvation survival up to 3 months

-function to insulate

-Saponification: formation of soap

Phospholipids - main component in cell membrane

head is hydrophilic

2 fatty acid tails are hydrophobic

rigid backbone of 4 fused together carbon rings

most common is cholesterol

Nucleotide = ribose

Bases = adenine (A), Uracil (U), Cytosine (C) and Guanine (G)

A=U and C=G

Single stranded - secondary structure

contains instructions for growth & development

Nucleotide = deoxyribose

Bases = adenine (A), Thymine (T), Cytosine (C) and Guanine (G)

A = T and C = G

Double helix; antiparallel

-phospholipid bilayer

-carries many proteins that carry out metabolic processes

In both prokaryotic and eukaryotic cells

outer cell membrane that encloses the cytoplasm

Controls what comes in and out of the cell

cytoskeleton element -- largest element

composed of protein tubulin

arise from microtubule organizing centers (MTOCs)

polar & dynamic

involved in shape, mobility, cell division

form spindle fibers that chromosomes attach to be moved

composed of nucleotides

single-stranded RNA and double-stranded DNA

sugar phosphate backbone

chain of amino acids linked by peptide bonds

links amino group of one amino acid to carboxyl group of another amino acid

Levels of protein structure

primary (sequence), secondary (structure), tertiary (one chain) and quaterary (multiple chains)

11

A-1-A-2-A-3-A-4-A-5-A-6-A-7-A-8-A-9-A-10-A (11 A (amino acids)

contains amino group (NH2) and carboxyl group (-COOH) and hydrogen

one r-group (variable)

20 amino acids in proteins

organism that makes its own food using carbon from CO2 and energy from light or inorganic substances

Example: plants

organisms that obtain carbon from organic compounds assembled by other organism

get energy from eating plants and one another

Example: animals

1. Chlorophyll A & B

2. Carotenoids

3. Xanthophylls

4. phycobilins

5. anthocyanins

Pigment that reflects red

In red algae & cyanobacteria

pigment that reflects yellow, orange & red -- Absorbs blue-violet & blue-green

In plants, algae & cyanobacteria

Antioxidant (neutralize oxygen radicals)

Doesn't contain oxygen (only difference from xanthophylls)

Accessory pigment

lutein (yellow) found in plants

yellow, brown, purple or blue

contains oxygen (only difference from carotenoids)

-alternating single & double bonds

-bonds represent shared electrons between carbon atoms

1. carotenoids

2. xanthophylls

3. phycobilins

4. anthocyanins

pigment that reflects blue-green

in plants, green algae & cyanobacteria

Absorbs violet & red light

pigment reflects yellow-green

In all plants, algae & cyanobacteria

Absorbs violot & red light

pigment that reflects blue-green

In plants, green algae & cyanobacteria

Absorbs violet & red light

-stored as triglycerides & broken down to glycerol & fatty acids

-Glycerol converted to PGAL and enters glycolysis

-Fatty acids converted to Acetyl CoA and enters Kreb cycle

-proteins are broken down to amino acids

-Amino group is removed and forms ammonia which is converted to urine and excreted

-Carbon backbones enters the Kreb cycle or it's preparatory reactions

1. Diffusion

2. Dialysis

3. Facilitated Diffusion

4. Osmosis

5. Filtration

-Passive transport

-Carrier protein in plasma membrane accelerates movement of relatively large molecules from region of higher to region of lower concentration

-passive process that requires a protein for movement of a solute across a membrane

-passive transport

-hydrostatic pressure pushes water & nutrients across membrane (across walls of small blood vessels)

Example: Kidneys

1. Bulk transport

2. endocytosis

- phagocytosis and pinocytosis

3. exocytosis

4. receptor-mediated endocytosis

1. Aerobic pathway

2. Anaerobic pathway

- energy-releasing pathway

- evolved later

- requires oxygen

- Starts in cytoplasm with glycolysis and ends in mitrochondria

-Extract energy from glucose

RuBP

Ribulose biphosphate

1. PGA (phosphoglycerate)

2. PGAL (phosphoglyceraldehyde)

-energy-releasing pathway

-evolved first

-doesn't require oxygen

-starts in cytoplasm with glycolysis and ends in cytoplasm

-common among prokaryotes and protists that live where oxygen is absent

Rubisco

Found on the stromal surface of the thylakoid membrane

In the Calvin Benson Cycle, what is the most abundant protein on earth?

Where is it located?

Catalyzes CO2 fixation to RuBP

2 catalytic activities are oxygenase & carboxylase

the stomata closes on hot, dry days increasing the oxygen level & lowering the CO2 level.

Rubisco attaches RuBP to O2 instead of CO2

Forms 1 PGAL instead of 2

In C3 plants

- neoplasm

- cancerous

- grow & divide abnormally disrupting surrounding tissues physically & metabolically

- neoplasm

- noncancerous

- grow slowly & retain surface recognition protein that keep them in a home tissue

1. benign

2. malignant

abnormal masses of cells that lost controls over how they divide and grow

benign & malignant

- descendents of tumor cells from a woman named Henrietta Lacks

- line of human cancer cells that can be grown in culture

-not all cells can be grown in culture

-growing cells in culture allows researchers to investigate processes & test treatments w/o danger to patients

-during transition between prophase I and metaphase I

-microtubules from spindle poles attach to kinetochores of chromosomes

the phenotype of the heterozygotes (Aa) cannot be distinguished from one of the homozygotes (AA)

Example: Gerbils

AA = brown; aa = black; Aa = brown

No way can tell is AA or Aa

Heterozygote phenotype is somewhere between that of two homozygotes - often described as blending though the alleles themselves don't blend - The phenotype look like the two traits have blended together

Example: Snapdragons: If have one red (AA) and one white (aa) - a pink snapdragon will be produced.

The reason is that homozygous red plant produces a lot of pigment and the homozyous white produces no pigment so the heterozygote will produce half as much of the homozygous red

(Note: there is no dominant allele)

Ration for F1 generation is 1:2:1 (has the same genotypic and phenotypic ratios)

phenotype of the heterozygote includes the phenotypes of both homozygotes

Example: ABO blood types - A and B are both expressed

Example: have a dark green clover and a light green clover - will produce a clover with both light green and dark green pigment expressed

No dominant allele

1. Interphase

2. Prophase

3. Metaphase

4. Anaphase

5. Telophase

6. Cytokinasis

DNA replicated but has not formed the condensed structure of chromosomes.

They remain loosely coiled chromatin

Chromatin condenses into discrete chromosomes

spindles form at opposite "poles" of the cell

Nuclear envelope breaks down

located in moist temperate zones

Examples: sunflowers, beans.

in subtropical regions

CO2 fixed twice in different cells

Example: Sugar Cane

In very hot climates

Carbon fixed twice in same cell

Day (stomata closes) & reopens at night

Allows researchers to:

1. investigate basic genetic processes

2. reconstruct life's evolutionary history

3. devise counterattacks against rapidly mutating pathogens

enzymes that chop up viral DNA at a specific sequence

Number of cuts depend on number of times "target" sequence occurs

G1

S

G2

DNA sequences are repeated two or more times

Can occur through unequal crossovers in Prophase I

Loss of some part of the chromosome

most are lethal or cause serious disorders

part of the sequence of DNA within the chromosome becomes oriented in the reverse direction with no molecular loss

May not affect the carrier's health but can affect fertility

Crossovers in inverted region during meiosis may result in deletions or duplications that affect the viability of the forthcoming embryos

If a chromosome breaks, the broken part may get attached to a different chromosome or different part of the same chromosome

Most are reciprocal or balanced - two chromosomes exchange parts

Philadelphia Chromosome - Chromosome 9 and 22 change places

-Associated with cancer, chronic leukemia

a complete molecule of DNA and its attached proteins

carries part or all of an organism's genes

linear in eukaryotic cells

circular in prokaryotic cells

one or more chromosomes do not separate during mitosis or meiosis

gametes with the wrong number of chromosomes

Anaerobic pathway that breaks down glucose and forms ethanol and ATP

Begins in glycolysis

End reactions regenerate NAD+ so glycolysis can continue

Net yield: 2 ATP per glucose

Anaerobic pathway that breaks down glucose; forms ATP & lactate

Starts in glycolysis

End reactions regenerate NAD+ to continue glycolysis

Net yield: 2 ATP per glucose

Active transporter that pumps 3 sodium ions out across the plasma membrane for every 2 potassium ions pumped in

(High concentrations of potassium and low concentrations of sodium)

active transport that utilizes energy of ATP hydrolysis to transport various substrates across cellular membrane

Pumps out toxin & drugs from the cells

Through the Cori Cycle

metabolic pathway in which lactate is produced by anaerobic glycolysis in the muscles move to the liver and is converted to glucose which then returns to the muscles and is converted back to lactate

diploid cells have pairs of genes, on pairs of homologous chromosomes.

The 2 genes of each pair are separated from each other during meiosis, so end up on different gametes

three alleles

gene that controls ABO type codes for enzyme that dictates structure of a glycolipid on blood cells

2 alleles A and B are codominant when paired

3rd allele O is recessive to the others

one gene may influence two or more traits

Example: Marfan syndrome - genetic disorder that arises from mutations in fibrillin gene

Tyrosinase - heat-sensitive enzyme

enzyme catalyzes one step in the synthesis of brown/black pigment melanin only in cooler regions (legs, tail, ears)

Yarrow plant - genetically identical but grow differently at different elevations

transcribes the retroviral RNA into a complementary DNA (cDNA) to form a DNA:RNA hybrid

DNA synthesis is primed by a host cell tRNA whose 3' end is partially unfolded to base pair with the viral RNA & all RNA tumor viruses contain a reverse transcriptase

1 - must be able to cut & rejoin DNA at precise location

2 - select DNA molecule to serve as carrier (vector)

3 - prepare & insert foreign DNA

4 - Introduce vector into host organism (process called transformation)

5 - Screen for host cells replicating the hybrid DNA

small circles of DNA with just a few genes

Bacteria can usually survive without plasmids

Used to carry foreign DNA to host cells & are called cloning vectors