ch.11-14 Flashcards by Annmarie Bradley

DNA 4 types of nucleotides and their pairings

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
A=T
C=G

How well did you know this?

Not at all

Perfectly

DNA structure

double helix

How well did you know this?

Not at all

Perfectly

What does DNA replication require?

Unwinding– helices
Complementary base pairing
Joining– DNA polymerase and DNA ligase

How well did you know this?

Not at all

Perfectly

Semiconservative replication

parent strands unwind and separate due to the actions of the helicase

How well did you know this?

Not at all

Perfectly

DNA replication in the Eukaryotes

Forms “replication bubbles”
bubbles spread in both directions until they meet

How well did you know this?

Not at all

Perfectly

Protein synthesis

Major enzymes
Transcription and Translation
Take a DNA strand and decipher the amino acid code using a codon chart

How well did you know this?

Not at all

Perfectly

RNA structure and function

Ribonucleic acid
Uses uracil, not thymine
single stranded

How well did you know this?

Not at all

Perfectly

Three major types of RNA

Messenger RNA(mRNA)
Transfer RNA(tRNA)
Ribosomal RNA(rRNA)

How well did you know this?

Not at all

Perfectly

Messenger RNA(mRNA)

produced in the nucleus from the DNA template
carries genetic information

How well did you know this?

Not at all

Perfectly

Transfer RNA(tRNA)

produced in the nucleus from the DNA template
transfers amino acids ribosomes

How well did you know this?

Not at all

Perfectly

Ribosomal RNA(rRNA)

produced in the nucleus
nucleolus of the nucleus from the DNA template
joins proteins to form ribosomes

How well did you know this?

Not at all

Perfectly

Sir Archibald Garrod

first to suggest the link between genes and proteins

How well did you know this?

Not at all

Perfectly

Transcription

DNA serves as a template to make RNA
complementary RNA is made from a DNA template
bases join in order dictated by the sequence of bases in the template DNA strand

How well did you know this?

Not at all

Perfectly

Translation

mRNA directs the sequence of amino acids in a protein
rRNA and tRNA assist

How well did you know this?

Not at all

Perfectly

Translation 1

tRNA brings amino acids
Anticodon– a group of three bases complementary to a specific codon of mRNA

How well did you know this?

Not at all

Perfectly

Translation 2

Ribosomes are composed of protein and rRNA
site of translation— protein
P site– for a tRNA attached to a peptide
A site– for newly arrived tRNA with an amino acid

Translation 3

Initiation: mRNA binds to the small subunit of a ribosome, large subunits then join
Elongation: peptide lengthens 1 amino acid at a time
Termination: 1 of 3 codons reached
release factor causes ribosomal subunits and mRNA to dissociate
complete polypeptide released

Lac operon

when lactose is present it binds to the repressor

Fossil evidence

fossils trapped in rock strata are the fossil record that tells us the history of life

Finches

ground-dwelling finches: beak size depends on the size of the seeds they eat
speciation: formation of new speciation— occurred because the isolated population evolved independently of the mainland population

Galápagos island tortoise

long-necked tortoises: in dry areas where food is scarce
short-necked tortoises: in most regions with an abundance of food
adaptation: any characteristics that make an organism more suited to its environment

Natural Selection

mechanism for evolution
the process that results in the evolution of organisms well adapted to their environment

Natural selection requires

members of a population have heritable variation
more offspring produced than can be supported
individuals with favorable traits to survive and reproduce more than those lacking traits

Stabilizing selection(the most common form of selection)

occurs when an intermediate phenotype is favored
extreme phenotypes selected against individuals near the average are favored

Disruptive selection

two or more extreme phenotypes are favored over the intermediate phenotype British land snails and thrushes

Directional selection

occurs when an extreme phenotype is favored occurs when a population is adapting to a changing environment

Genetic drift

refers to change in allele frequencies of a gene pool due to chance allele frequencies "drift" over time depending on which member dies, survives, or produces more likely in small populations more likely to lose rare alleles

Two types of genetic drifts

bottle neck founder effect

Bottle neck effect

species suffer a near extinction and only a few survivors go on to produce the next generation

Founder effect

rare alleles occur at a higher frequency in a population isolated from the general population *alleles carried by founders are dictated by chance alone

Genetic mutation

ultimate source for allele differences the adaptive value of mutation depends on current conditions *no variation without mutation

Gene flow

"gene migration" movement of alleles among populations by migration of breeding individuals can increase variation within the population by introducing novel alleles from another population continued gene flow reduces differences among populations-- can prevent speciation

Non Random mating

selection of mates according to genotype or phenotype(no chance) Assortative mating: tend to mate with individuals with the same phenotype sexual selection: favors characteristics that increase the likelihood of obtaining mates

Microevolution

individuals did not evolve as evolution occurs, genetic and phenotypic changes occur within a population small measurable evolutionary changes within population from generation to generation

Hardy Weinburg Equilibrium

states that an equilibrium of allele frequencies in a gene pool will remain in equilibrium as long as 5 conditions are met

Hardy Weinburg Equilibrium requirements

no mutations no gene flows random mating no genetic drifts no selections

Causes of Microevolution

genetic mutation gene flow nonrandom mating genetic drift natural selection

Hardy Weinburg Equilibrium formula

p^2+2pq+q^2=1