GN311 Exam3

What genetic changes can impact biochemical pathways

mutations in the enzymes within the step wise reaction

How does biochemical pathways use epistatic interactions

needs enzymes to move through intermediates

What is the difference between a mutation in somatic vs germline cells

germline is passed through generatin while somatic isn’t

What is a gain of function mutation

Cell produces protien with additional function, completes unintended actions

What is a loss of function mutation

protien looses purpose, partialy or completely

What is a silent mutation

synonymous, no change in AA

What is a nonsense mutation

codon changes to a stop codon

What is a missense mutation

non synonymous, Changes AA

What is a nuetral missense mutation

no notable change in function of protein

What is a transition

purine to purine, pyrimidine to pyrimidine

What bases are purines

A/G

What bases are Pyrimidines

T/C/U

What is a transversion

pyrimidine to purine

What is a read through mutation

Stop codon changes to non-stop codon

What are the three spontaneous point mutations

depurination, deamination, and wobble

What is depurination

removed bond at purine, apurnic site, gap in DNA

What is deamination

replaces CG with U, making AT during replication

What is wobble pairing

miss pairings due to flexible helix, needs two rounds of replication to alter both strands

What happens to the functionality of a protein with a frameshift mutation

Almost always is non-functional

What is a intercalating agent

slips betwen bases distorts helix, cause frameshift mutation=poly stutters

What causes template slippage

intercalating agents

What happens with unequal crossing over

different sizes of stands and frameshift mutations

What are the three mutagens

Alkylating bases, deamination, and hydroxlamine

What is the mutagen Alkylation

an ethyl group replaces a oxygen, making g match with t

What is the mutagen deamination

NH2 group replaced by oxygen, c turns into U

What is the mutagen hydroxylation

NH2 is replaced with OH, making c match with A

How does X-rays affect the genome

breaks phosphodiester bonds and causes point mutations

How does UV light affect the genome

creates thymine dimers which distorts helix and inhibits replication

What is a dimer

bond between bases on same strand that distorts helix

How does transposable elements affect the genome

they are nearby genes that copy and paste themselves into functional gene changing the function of the gene

What is a Ac transposable element?

An activator, creates the transposase

What is ds transposable element

dissociation or deletion, needs Ac to move, what is getting placed in the genes

What happens for a direct repair in bacteria of pyrimidine dimers

photolyase aborbs light and clips dimer

What happens in with the direct repair methyltransferase

removes methyl group to restore guanine

What happens with proof reading in both prokaryotes and eukaryotes

DNA poly stalls, exonuclease removes inncorect nucleotide and DNA poly replaces base.

What happens in mis-matached repair (MMR)

MMR proteins find incorrect base, exonuclease cuts section around base, DNA poly rebuilds, doesn’t remove lesions

What happens in Nucleotide Excision Repair(NER)

Uses SSB to hold strands apart, dimered DNA cut, DNA poly fills gap, removes lesions

What is a lesion

damaged DNA

What happens in a Base Excision Repair(BER)

glycosylases remove defective bases making a apurinic site, AP endonuclease removes phosphodiester bond next to base and DNA poly rebuilds

What are the two types of a double strand break

Nonhomologous end joining(NHEJ) and Homologous recombination repair(HRR)

What is nonhomologous end joining

when no sister available joins broken ends, mutations common

What is homologous recombination repair

sister is available and used as a template

What happens in translesion DNA ploymerase bypass

some polymerases can skip over lesions in replication, often leading to errors

How do proteins bind to DNA

Transcription factors

What is positive control

activator protein bind to DNA to increase transcription

What is negative control

repressor binds to DNA to stop transcription

What is inducible control

transcription turns on in presence of small molcule

What is repressible control

transcription turns off in presense of small molecule

What is constitutive expression

gene is always on because repressor cannot bind to the DNA

What does the lacZ gene code for

b-galactrosidase

What does the lacY gene code for

permease

In negative control is the lac gene transcription off or on with no lactose

off

In negative control is the lac gene transcription off or on with lactose

on

In positive control is the lac gene transcription off or on with no lactose

off

In positive control is the lac gene transcription off or on with lactose

on

What does the lacI gene code for

the repressor

What does the lacO gene code for

the attachment of the repressor

What does the lac P gene code for

the attachment of the RNA polymerase

What is monosomic

missing chromosome

What is nullsomic

double missing chromosome

What is trisomic

extra chromosome

triploid is what

3 copies of chromosomes

What is tetraploid

4 copies of every chromosome

What is autopolyploidy

extra sets of homosomes from same species

What is anopolyploidy

chromosomes from multiple species

What causes sterility for polyploidy organisms

nondisjunction in mitosis

What is amphidiploids

allopolyploid that behaves likea diploid

What does maternal genes do for development of drosophila

establishs anterior and posterior polarity

what does segementation genes do

number and polarity of genes

What are the three types of segmentation gene

gap genes, pair rule genes, segment polarity genes

Is bicoid in anterior or posterior

anterior

Is Nanos in anterior or posterior

posterior

Is caudal present in the anterior or posterior end

posterior

Does bicoid repress or activate caudal

repress

Where is hunchback concentrated

anterior

does nanos inhibit or promote hunchback transcription

inhibit

What do homeotic genes do

gives identity to segments, ordered anterior to posterior

What is the antennapedia complex

5 genes, head and anterior thorax

What is the bithorax complex

posterior thoraz and abdomen 3 genes

What is a homeodomain

protein created from a homoebox(has tf)

What is a homeobox

common DNA sequences

What does class a genes affect

sepals and petals

What does class B gene affect

petal and stamens

What does class C genes affect

stamens carpels

What is somatic recombination of b cells

helps create and store different b antibodies by changing variable regions

Structure of antibodies

heavy+light combine to create variable region

What type of regulation is trp

negative repressible

What happens in lack of trp in trp operon

repressor cannot bind and transcription happens

What happens with trp present in trp operon

binds to repressor to activate it and no transcription takes place

What is the attenuator for the trp operon

in leader sequence and decreases transcription when trp is present

what is anti sense RNA

bind to mRNA to inhibit transcription

What is a riboswitch

regulates transcription

What is a DNasel hypersensitive site

upstream of transcription where regulartory protiens bind to in eukaryotes

Histone deacetylation

tightens DNA to histones with lys

Histone acetylation

losens DNA from histone with lys

What does methylation of DNA do to transcription

changes transcription rate