Lecture 3/10

Question 1

what do release factors do for proks at the end of translation?

Answer 1

cleave the polypeptide chain and disassembles and releases the ribosomal subunits and the tRNA

Question 2

what are the main differences between prok and euk translation?

Answer 2

in euks the small subunit scans for the 5’ cap and then the Kozak sequence (ACCAUGG) to start translation

in euks, the first amino acid is Met, not fMet

Question 3

what is important to look for in the Kozak sequence

Answer 3

AUG with C two nts upstream and G one nt downstream to start translation

Question 4

what helps guide the ribosome to the 5’ cap?

Answer 4

initiation factors

Question 5

what helps unwind the 2ary structure of RNA

Answer 5

helicase

Question 6

peptide bond formation occurs when amino acids are in which sites in the ribosome?

Answer 6

P and A

Question 7

what is the 5’ UTR

Answer 7

the region of the transcript upstream of the initiator codon that doesn’t get translated

Question 8

what is the 3’ UTR?

Answer 8

the area downstream of the stop codon that doesn’t get translated

Question 9

are UTRs a specific size?

Answer 9

no, they can be long or short

Question 10

are UTRs always present? What is their function?

Answer 10

yes, and they’re for stability and contain sequences for regulation

Question 11

how can there be one transcriptional unit for an operon that encodes multiple proteins?

Answer 11

each gene has its own shine delgarno, AUG, and stop codon

Question 12

for translation in euks, what does each transcriptional unit need?

Answer 12

its own promoter and enhancer/repressor regions

Question 13

does each gene need a stop and start codon?

Answer 13

yes! even as part of the same transcript

Question 14

what is a DNA-dependent DNA polymerase?

Answer 14

template DNA, output DNA (like DNA polymerases)

Question 15

what is a DNA-dependent RNA polymerase?

Answer 15

DNA template, RNA output (ie. RNA polymerases and primase)

Question 16

what is a RNA-directed DNA polymerase?

Answer 16

template RNA, output DNA (ie reverse transcriptase and telomerase)

Question 17

what is a RNA-dependent RNA polymerase?

Answer 17

template RNA, output RNA

Question 18

what are proteins phosphorylated by?

Answer 18

kinases

Question 19

what is a phenotype?

Answer 19

observable characteristic

Question 20

what is an allele?

Answer 20

the alternative possibilities for each gene (every gene has multiple alleles)

Question 21

what is genotype?

Answer 21

a pair of alleles in a diploid individual

Question 22

what does +/+ stand for?

Answer 22

WT

Question 23

what does a/z stand for

Answer 23

het

Question 24

what does the het phenotype define?

Answer 24

the dominant allele

Question 25

if +/z are WT phenotype, which allele is dominant?

Answer 25

WT allele

Question 26

what does a dash represent in a GT? (like +/-)

Answer 26

an unknown GT, so +/- means either +/+ or +/z

Question 27

what is the result of a LOF mutation?

Answer 27

reduced or abolished protein activity

Question 28

what is a null/amorphic mutation

Answer 28

a mutation that completely blocks the function of a gene product (ie. deletion of an entire gene or early stop codon)

Question 29

what is a hypomorphic mutation?

Answer 29

gene product has weak, but detectable activity, may or may not be sufficient

Question 30

what is haploinsufficient?

Answer 30

one WT allele doesn't produce enough protein on its own to produce a WT phenotype

Question 31

where are you most likely to find haploinsufficient genes?

Answer 31

development

Question 32

what is a trans het?

Answer 32

a WT with a mutated copy or just two mutated copies

Question 33

are GOF mutations usually recessive or dominant?

Answer 33

dominant

Question 34

what is a hypermorphic mutation?

Answer 34

it generates more gene product or the same amount of a more efficient gene

Question 35

why are GOFs bad?

Answer 35

gives you too much protein

Question 36

where are the mutations that affect the protein itself (ie. making a more efficient gene product) found?

Answer 36

on exons

Question 37

where would you find the proteins that make more transcript and more protein?

Answer 37

in the regulatory regions

Question 38

what is a neomorphic mutation?

Answer 38

it generates a gene product with new function or that is expressed at inaproppriate time or place

Question 39

what is a nonsense mutation

Answer 39

codon for an amino acid is changed to a stop codon

Question 40

what does the severity of a nonsense mutation depend on?

Answer 40

location on the protein, the earlier it is the worse it will be for protein function

Question 41

where are nonsense mutations found? why?

Answer 41

exons only! it has to be in the coding region, can't be in the intron

Question 42

what happens to many proteins truncated by nonsense proteins?

Answer 42

they might be unstable and therefore degraded since it can't fold correctly

Question 43

what do frame shift mutations cause and what are they?

Answer 43

insertion or deletion of a block of one or more proteins from the DNA (not multiples of a codon) and disrupts the translational frame

Question 44

where are frameshift mutations found?

Answer 44

exons

Question 45

what are point mutations?

Answer 45

single nucleotide substitutions (either transition or transversion -- these can change what the amino acid will be

Question 46

what kind of mutations don't alter the gene product/amino acid sequence and why?

Answer 46

silent mutations, and because of wobble!

Question 47

what are missense mutations?

Answer 47

one amino acid is substituted with another

Question 48

what are the 2 types of missense mutations?

Answer 48

conservative and non-conservative

Question 49

what is a conservative missense mutation?

Answer 49

substituted amino acid has similar chemical properties to WT amino acid

Question 50

what is a non-conservative missense mutation?

Answer 50

substituted amino acid has different chemical properties of WT amino -- will change the structure of the protein

Question 51

Mutations in DNA affect both ______ and ______

Answer 51

RNA and protein

Question 52

if you disrupt (with a mutation) where something is going to be sliced, that can also disrupt the ______

Answer 52

function

Question 53

what is an inversion?

Answer 53

a 180 degree rotation of a segment of DNA

Question 54

when would an inversion mutation occur?

Answer 54

during recombination

Question 55

what is a reciprocal translation

Answer 55

parts of 2 nonhomologous chromosomes change places, effect depends on whether it's at the coding region of a protein

Question 56

are mutations that affect protein levels found in or outside of the protein coding regions? what kinds of mutations are these?

Answer 56

outside! point, deletion, substitution