Week 11 (Gene structure and expression)

Question 1

central dogma

Answer 1

DNA - replication
RNA - transcription
Proteins - translation

Question 2

rRNA

Answer 2

site of polypeptide assembly

Question 3

tRNA

Answer 3

transports and positions amino acids

Question 4

mRNA

Answer 4

directs which amino acids are assembled into polypeptides

Question 5

snRNA

Answer 5

is involved in splicing

Question 6

transcription

Answer 6

-synthesize any type of RNA from a DNA template
-DNA strand provides template for complementary RNA strand

Question 7

translation

Answer 7

-occurs at ribosomes
-mRNA is used to determine the amino acid sequence of a polypeptide

Question 8

genetic code

Answer 8

-unambiguous
-nearly universal
-redundant

Question 9

ORF and what terminus

Answer 9

start (AUG) N terminus to stop codon C terminus

Question 10

each amino acid in a protein is specified by ____

Answer 10

a codon

Question 11

triplet code

Answer 11

64 codon combinations

Question 12

start of transcription

Answer 12

when RNA polymerase binds to a promoter (binding site on template strand of DNA)

Question 13

how many of the 2 DNA template strands is transcribed

Answer 13

only 1

Question 14

RNA polymerase

Answer 14

-adds ribonucleotides to the growing 3’ end of an RNA chain
-does NOT need a primer

Question 15

which way does the template strand run

Answer 15

3’ to 5’

Question 16

which way does complementary strand run

Answer 16

5’ to 3’

Question 17

what signals the end of transcription

Answer 17

the terminator

Question 18

how many RNA polymerase does eukaryotes have

Answer 18

3

Question 19

how pre mRNA is modified

Answer 19

5’ cap - protects mRNA
3’ poly A tail - prevents hydrolysis

Question 20

Introns

Answer 20

spliced out (non coding )

Question 21

Exons

Answer 21

spliced together to be translated into amino acids

Question 22

spliceosome and what is made up of

Answer 22

made from snRNPs and does splicing
(RNA and proteins)

Question 23

ribozymes

Answer 23

RNA molecules that catalyze chemical reactions

Question 24

RNA splicing

Answer 24

removing introns and keeping exons

Question 25

how many nucleotides are moved at at time in translation

Answer 25

3

Question 26

what begins translation

Answer 26

when portion of mRNA binds to a ribosome

Question 27

SSU

Answer 27

small ribosomal subunit -acts first settles on 5’ end

Question 28

LSU

Answer 28

large ribosomal subunit -settles down on top

Question 29

translation : initiation

Answer 29

-tRNA has a anticodon on its bottom which base pairs with codons in mRNA -Met binds to AUG on mRNA

Question 30

activating enzymes

Answer 30

aminoacyl tRNA Synthetase -attaches the appropriate amino acid to its corresponding tRNA

Question 31

translation: elongation

Answer 31

-new amino acids enter with tRNA to the A site -LSU transfers the polypeptide from the P site to the new amino acid -moves 3 nucleotides over -old tRNA leaves out of E site (exit)

Question 32

translation : termination

Answer 32

stop codons are recognized by release factors that release the newly made polypeptide from the ribosome

Question 33

prokaryotic mRNA vs euk

Answer 33

pro- polycistronic euk- monocistronic

Question 34

what is special about prokaryotic mRNA

Answer 34

they are often translated before transcription is complete

Question 35

what is a large scale mutation

Answer 35

long segments of DNA are affected

Question 36

what are point mutations

Answer 36

chemical change in just one base pair of a gene

Question 37

types of point mutations

Answer 37

silent - replacement of a pair of complimentary nucleotides with another as long as it doesn’t change structure of function missense - same as silent but changes structure or function of protein nonsense- changes an amino acid codon to a stop codon

Question 38

framesshift mutations

Answer 38

-single insertions or deletions that affect open ready frame ORF -groups of 3 do not cause a frame shift

Question 39

where do mutations affect

Answer 39

affect DNA replication and transcription

Question 40

what is an operon

Answer 40

cluster of genes under the control of a single promoter

Question 41

operator

Answer 41

dna sequence in which the represor protein may bind

Question 42

represor protein

Answer 42

protein that only binds to the operator inhibits transcription

Question 43

activator protein

Answer 43

protein that that binds near the promotor and enhances transcription

Question 44

inducer

Answer 44

molecule that inactivates a represor protein

Question 45

corepressor

Answer 45

actives the represor protein

Question 46

jacob and monod proposed what

Answer 46

operon model for bacterial gene expression

Question 47

inducible gene

Answer 47

normally turned OFF but can be turned ON -> lac operon

Question 48

repressible gene

Answer 48

normally turned ON but can be turned OFF ->trp operon

Question 49

positive control

Answer 49

uses an activator protein

Question 50

negative control

Answer 50

uses a represor protein

Question 51

allolactose

Answer 51

inactivities the represor, removing it from the operator

Question 52

lac operon

Answer 52

-transcribed only when lactose is present

Question 53

when lactose is absent lac operon is ____

Answer 53

OFF

Question 54

when lactose is present lac operon is ____

Answer 54

ON

Question 55

when glucose is low cAMP levels are ______ and binds to ____

Answer 55

high binds to CAP protein

Question 56

when glucose is high cAMP levels are ______ and what doesn’t bind

Answer 56

low and CAP doesn’t bind

Question 57

when trp is present the trp operon is _____ the operator is _____

Answer 57

OFF and bound

Question 58

when the is little or no trp the operon is ______ and ______ and the operator is _____ bound

Answer 58

ON and transcribed and not bound