Biology Final

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Who discovered the structure of DNA?

Watson & Crick

Gregor Mendel

showed how traits passed from one generation to another

Frederick Griffith

showed that traits could be passed by the transfer of molecules

Frederick Griffith's Experiment with mice

-injected bacteria into mice
-2 types of streptococcus: smooth and rough
-smooth bacteria killed mice
-rough bacteria mice lived
-boiled smooth bacteria mice lived
-mixture of boiled smooth and living rough mice died

transforming factor

the dead cells from the smooth boiled bacteria transferred a trait to still living in the mice and killed them. Rough bacteria transferred to smooth

Hershey and Chase experiment

-used bacteriophage
-to determine what is being passed from one generation to another

Bacteriophage experiment

-phage injected then makes more phage
-original phage stays outside and injects phage
-protein- injects radioactive sulfer
-DNA- injects radioactive phosphate
-DNA found in the phage

base pairs

A-T
G-C

Pyrimidines

T & C

Purines

A & G

Ribose

H group

deoxyribose

no oxygen

What link nucleotides to each other in DNA?

phosphodiester bonds

hydrogen bonds

temporary and weak-impermanet
lots of them make strong

histomes

DNA wrap around this

Denaturation

denature strands of DNA (break apart)

The entire human genome is how big?

3.2 billion base pairs long

DNA replication

conservative: no change, copy
semiconservative: original strand, separated then copied to turn into daughter cells
dispersive: DNA copied in sections

build new strands of DNA

rule of complementary
A&T G&C

what is the original stand of DNA

template

The DNA is a nucleus is organized by being wrapped around histome proteins in a beads on a string structure known as...

nucleosome

5 prime

phosphate

3 prime

hydroxyl group (OH)

Which enzyme cannot synthesize a nucleic acid chain from scratch (without a primer)?

DNA polymerase

DNA polymerase

-moves in the 5 to 3 direction
-it needs a primer

what unwinds a DNA helix

Helicase

stabilize single stranded DNA and prevent the two strands at the replication fork from reforming double stranded DNA

single stranded binding proteins

avoids twisting of the DNA ahead of replication fork by cutting the DNA, turning the DNA on one side of the break in the direction opposite of that of the twisting force, and rejoining the two strands again

topoisomerase
(relaxes DNA)

synthesizes RNA primer in the 5 to 3 direction to initiate a new DNA strand

Primase

main replication enzyme in E.coli. extends the RNA primer by adding DNA nucleotides to it.

DNA polymerase III

tethers DNA polymerase III to the DNA template, making replication more efficient

sliding DNA clamp

seals nick left between adjacent fragments after RNA primers replaced with DNA

DNA ligase

leading strand of DNA synthesis

synthesized continuously

lagging strand of DNA synthesis

synthesized discontinuously

evolution

change in the genetic composition of a population from generation to generation

elements

composed of individual atomos

molecule

2 or more atoms of 1 element

atomic number

is the number of protons in the nucleus

atomic mass

sum of the protons and neutrons

4 most common elements

CHON
Carbon, Hydrogen, Oxygen, Nitrogen

trace elements

those required by an organism in small quantities

4 most important chemical linkages in biological molecules

chemical bonds

electrical attraction cation(-) and anion(+)

ionic bonds

electron sharing (polar & nonpolar)

covalent bonds

partially charged atoms. individual ones are weak, bond with oxygen, nitrogen and sulfur, weak unless there is a lot

hydrogen bonds

weak forces that develop over very short distances between nonpolar molecules (equal sharing)

Van der Waala Force

4 properties of water

1. cohesive behavior (allow ppl to walk on water)
2. ability to moderate temp
3. expansion upon freezing
4. versatility as a solvent

cohesion

hydrogen bonds hold water molecules together

adhesion

an attraction between different substances
(allow water to travel up the plants cell wall)

surface tension

is a measure of how hard it is to break the surface of a liquid

moderation of temperature

-water absorbs heat from warmer air and releases stored heat to cooler air
-water can absorb or release a large amount of heat with only a slight change in it own temp.

evaporation cooling

transforming from a liquid to a gas

heat of vaporization

how hot we have to get to sweat
is the heat a liquid must absorb to be converted to gas

hydration layer

water forms around the charged molecules

solvent

water

solute

is whats being dissolved

buffers

substances that neutralize acids and bases

tetravalence

carbon can form 4 covalent bonds with a variety of atoms
-valence is the number of covalent bonds that an atom can form

hydrocarbons

are organic molecules consisting of only carbon and hydrogen

enantiomers

mirror images fo each other, typically only one of the 2 can enter a reaction

structural isomers

same chemical formula but atoms are arranged different ways

isomers

2 or more molecules with the same chemical formula, but different molecular structures

polymer

long chains of monomers

monomers

carbohydrates, proteins, lipids, nucleic acids

dehydration reactions

2 monomers are covalently bonded through the loss of water molecule

hydrolysis

covalent bonds between 2 monomers are broken by the addition of water molecules
(broken down by adding water molecules)

neutral lipids

fatty acid: a single hydrocarbon chain with a carboxyl group
oils: are liquid at biological temperatures
fats: are semisolid
saturated: have no double bonds between individual carbon atoms of the fatty acid chain

unsaturated

at least one double bond. where double bonds are formed, hydrogen is eliminated (kinked)

phospholipids

primary lipids fo cell membranes
-hydrophobic tails and hydrophilic heads
-when added to water, they self assemble a bilayer, with the hydrophobic tail pointing toward the interior

steroids

lipids characterized by a carbon consisting of 4 fused rings

proteins

enzymes
structural support
storage
transport
cellular communication
movement
defense against foreign substances

amino acids

organic molecules with carboxyl and amino groups

peptide bonds

link amino acids through dehydration synthsis

primary structure

the unique sequence of amino acids
-determined by inherited genetic information

secondary structure

coils, folds, random coils and loops
-alpha helix and beta pleated sheet

tertiary structure

overall three dimensional shape or conformation
-interaction among various side chains (R group)

Quaternary structure

several proteins, how they bond
-protein consists of multiple polypeptides

protein conformation

-also depends no the physical and chemical conditions of the proteins environment
-pH
-salt concentration
-temperature

denaturation

occurs when a protein loses its native structure
-a denatured protein is biologically inactive

nucleic acids

nucleic acids store and transmit hereditary information

nucleotides

the monomer of nucleic acids, consists of 3 parts linked together by covalent bonds

RNA based catalysts are called..

ribozymes

catalysts

speed up the rates of reactions by many millions of times without the need for an increase in temperature

potential energy

energy of position

kinetic energy

energy of motion

chemical energy

potential energy of the body

all living organisms exchange energy (fact)

living organisms are open systems

2 laws of thermo dynamics

1. energy can be transferred or transformed but it cannot be created or destroyed
2. every energy transfer or transformation increases the disorder (entropy) of the universe

exothermic reaction

spontaneous, release energy

endothermic reaction

absorbs energy, NOT spontaneou

spontaneous reactions

delta G is NEGATIVE

organisms reach equilibrium

-when delta G = zero
they Die

catabolic pathways

-delta G = negative
-spontaneous (cat falling)
-break it down
-exergonic

anabolic pathways

-positive delta G
-requires energy
-Never spontaneous
-build stuff up
-endergonic

exergonic reaction

-energy outward
-spontaneous
-negative
-releases energy

endergonic reaction

-energy inward
-absorbs free energy
-not spontaneous
-positive
-needs energy

hydrolysis of ATP

adds water-break apart

ATP

3 phosphate

ADP

2 phosphate

energy coupling

use an exergonic reaction to drive an endergonic one

phosphorylation

add phosphate to make ATP

enzymes do what?

speed up metabolic reactions without heat

ATP is..

recycled in the cell

catalyst

speed up reactions

active site

where the substrate binds to and a chemical reaction occurs

substrate

is a molecule upon which an enzyme acts

enzyme substrate complex

a complex composed of a substrate bound to the active site of an enzyme

cofactor

is a non protein chemical compound that is bound to a protein and is required for the proteins biological activity

coenzyme

a substrate that enhances the action of an enzyme

reactant

used during a chemical reaction to make the product

products

the final total

enzymes reduce activation energy

-creates the hump in the graph

enzymes stabilize the transition state

1. enzymes bring the reacting molecules together
2. enzymes expose the reactant molecules to altered charge environments that promote catalysts
3. enzymes change the shape of the substrate molecules (induced fit)

competitive inhibitor

binds to the active site

noncompetitive inhibitor

binds somewhere else; changes shape

feedback inhibition

end product switches off the metabolic pathway

allosteric regulation

enzymes function at one site is affected by the binding of a regulatory molecule at another site
-activators and inhibitors

evolution

change in the genetic composition of a population generation to generation

Natural Selection, Darwin's 4 observation

1. variations in traits within populations
2. traits are inherited from parents to offspring
3. all species are capable of producing excess offspring
4. many of these offspring do not survive

microevolution

-fine details
-short period of time
-small scale genetic changes in populations

macroevolution

-large time scale (dinosaurs)
-larger scale evolutionary changes in species and more exclusive groups

natural selection

survival

mutation

changes in DNA (spontaneous)

migration

stuff moving and change

random genetic drift

different genes

phylogeny

-everything started from 1 thing
-evolutionary history

genetic code

all organisms have the same

monophyletic

consists of the ancestor species and all its descendants

paraphyletic

grouping consists of an ancestral species and some, but not all, of the descendants

polyphyletic

grouping consists of various species that lack a common ancestor

2 sources of the SARS disease

1. civets
2. horse shoes flies

earliest evidence of life

3.4 billion years ago

methanogens

swamp gas

extreme halophiles

salt loving organisms

extreme thermophiles

hot places or cold areas

archaea

share traits with bacteria and eukaryotes

cell surface structures

1.cell wall
-maintains shape
-provides physical protection
-prevents the cell from bursting in a hypotonic environment
2. eukaryote cell walls are made of cellulose
3. most bacterial cell walls contain peptidoglycan

what is peptidoglycan

proteins on sugar backbone

gram positive

turns purple
big peptidoglycan layer

gram negative

turns pink
capsid on top layer

chemoautotrophs

oxygen, use CO2

chemoheterotrophs

oxygen, eat stuff

photoautotrophs

uses light for energy, use CO2

photoheterotrophs

uses light for energy, eat stuff

obligate aerobes

require oxygen for cellular respiratoin

obligate anaerobes

are poisoned by oxygen and use fermentation or anaerobic respiration

facultative anaerobes

can survive with or without oxygen

nitrogen fixation

take nitrogen gas from atmosphere make ammonium build amino acids and nucleic

how does bacteria reproduce

binary fission-cell divides, grows, DNA replication

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