Biochem - Prokaryotic Transcription

Front 1

what is the name for the portion of a gene that is copied into RNA?

Back 1

transcription unit

Front 2

what is the name for the strand of DNA that is identical to the RNA? Complementary to the RNA?

Back 2

coding strand; non-coding strand

Front 3

By convention, when the sequence of a gene is recorded, which strand is indicated?

Back 3

coding strand

Front 4

the region of RNA that encodes a protein is called what?

Back 4

coding region

Front 5

what is the sequence of the start codon? Of the 3 stop codons?

Back 5

AUG; UAA, UAG, UGA

Front 6

which protein catalyzes RNA synthesis?

Back 6

RNA polymerase

Front 7

what is the composition of the RNA pol core enzyme?

Back 7

a2bb’

Front 8

what is the composition of the RNA pol holoenzyme?

Back 8

a­2bb’σ

Front 9

is the promoter region located upstream or downstream of coding region?

Back 9

upstream

Front 10

what is the name for the first nucleotide in the transcription unit?

Back 10

transcription start site

Front 11

what is the position number for the transcription start site?

Back 11

1

Front 12

which subunit of the RNA holoenzyme is responsible for recognizing specific sequences in the promoter?

Back 12

σ

Front 13

which part of the RNA polymerase protein is responsible for the synthesis of the mRNA chain?

Back 13

core enzyme (σ falls off following binding of holoenzyme)

Hint 13

None

Front 14

what catalyzes mRNA elongation?

Back 14

release of pyrophosphate from the nucleoside triphosphate and hydrolysis of pyrophosphate into inorganic phosphate.

Front 15

Does RNA polymerase require a primer for mRNA production?

Back 15

no

Front 16

what is the term for cluster of adjacent gene coding regions which endode proteins required for a common metabolic process?

Back 16

operons

Front 17

do operons produce one or multiple strands of mRNA? What is a term to describe this mRNA?

Back 17

one; polycistronic

Front 18

how many genes are encoded in the lac operon?

Back 18

3

Front 19

what is the name of the area on the DNA that the repressor binds in situations of no lactose?

Back 19

operator

Front 20

how is the operator located in the lac operon in relationship to the promoter?

Back 20

downstream

Front 21

what is the name for the gene encoding the lac operon repressor? Is this gene facultatively or constitutively expressed?

Back 21

I gene; constitutively

Front 22

what is the term used to refer to the promoter and operator of the lac operon? To the repressor of the operon?

Back 22

cis-acting sequences; transacting sequence

Front 23

what is meant by cis-acting in relation to promoter and operator in lac operon?

Back 23

they must be physically connected to the genes they regulate

Front 24

what happens to the lac operon repressor in the presence of lactose?

Back 24

lactose binds the repressor and causes a conformational change which causes repressor-lactose complex to fall off operator sequence.

Front 25

does glucose trigger or repress production of lactose enzymes?

Back 25

repress

Front 26

what is the relationship between cAMP, CAP, and glucose for the lac operon?

Back 26

in the absense of glucose, levels of cAMP rise. cAMP binds to CAP, and this complex binds, in turn, to the lac promoter just upstream of the RNA polymerase.

Front 27

what effect does CAP-cAMP binding to promoter have on RNA polymerase activity?

Back 27

it causes RNA pol to bind more tightly to DNA and allows transcription to initiate more efficiently

Front 28

what does CAP stand for?

Back 28

catabolite activator protein

Front 29

in the presence of glucose and absense of lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?

Back 29

yes; low; no; no

Front 30

in the presence of glucose and lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?

Back 30

no; low; no; yes but at low levels

Front 31

in the absence of glucose and lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?

Back 31

yes; high; yes; no because the repressor wins

Front 32

in the absence of glucose and presence of lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?

Back 32

no; high; yes; yes, at high levels

Front 33

what are the three ways in which the RNA transcript is modified post-transcriptionally?

Back 33

capping, splicing, polyadenylation

Front 34

following transcription, a poly-A tail is added to which end of the RNA transcript? A cap is added to which end?

Back 34

3'; 5'

Front 35

are eukaryotic mRNAs poly- or monocistronic?

Back 35

monocistronic

Front 36

which two sites are essential for splicing of the introns?

Back 36

splice donor site and splice acceptor site

Hint 36

None

Front 37

what are gene families? Are they always located on the same chromosome?

Back 37

duplicated genes that are closely related but not identical, and that encode proteins with similar functions; no

Front 38

are repeats in 'junk' DNA identical in each individual?

Back 38

no

Front 39

what is an SNP? How many SNPs are present between pairs of human sequence?

Back 39

single nucleotide polymorphisms; 1 per 1000 base pairs