RNA & Transcription

Question 1

The degenerate code allows for what?

Answer 1

Multiple codons to encode for the same AA

Question 2

Initiation (start) codon

Answer 2

AUG –> Methionine

Question 3

Termination (stop) codon

Answer 3

UAA, UGA, UAG

Question 4

Mutation that affects one of the nucleotides in a codon

Answer 4

Point mutation

Question 5

Nonsense mutation

Answer 5

produces premature stop codon

aka truncation

Question 6

Missense mutation

Answer 6

substitution of one AA for another AA

Question 7

The three nucleotides of a codon are referred to as

Answer 7

the reading frame

Question 8

Mutation where some number of nucleotides are added or deleted from the mRNA sequence

Answer 8

Frameshift

Question 9

Enzyme that unwinds DNA double helix in transcription

Answer 9

Helicase & topoisomerase (prevents supercoiling)

Question 10

What is the name of the strand that mRNA is synthesized from?

Answer 10

Anti-sense strand (template)

Question 11

Enzyme responsible for synthesizing mRNA strand during transcription

Answer 11

RNA polymerase II

Question 12

Specialized DNA regions that initiates transcription of a particular gene

Answer 12

Promoter region

Question 13

RNA polymerase binding site in promoter region is known as

Answer 13

TATA box

Question 14

What helps RNA polymerase locate and bind the TATA box in the promoter region of DNA?

Answer 14

Transcription factors

Question 15

Major difference between RNA polymerase and DNA polymerase?

Answer 15

RNA polymerase does not require a primer to start generating a transcript like DNA polymerase does in replication

Question 16

What is the relationship between the mRNA strand and the coding (sense) strand?

Answer 16

They are exactly identical with the exception that all T residues are replaced with U residues in mRNA

Question 17

The first base transcribed from DNA to RNA is defined as

Answer 17

+1 base of that gene region

Question 18

T/F: no nucleotide in the gene is numbered 0

Answer 18

True

Question 19

Numbers to the left of the +1 start point (upstream, or toward 5’ of coding strand) are +/-?

Answer 19

negative

Question 20

Numbers to the right of the +1 start point (downstream, or toward the 3’ end of coding strand) are +/-?

Answer 20

positive

Question 21

Upstream refers to what end of both the coding/template strands?

Answer 21

5’

Question 22

Downstream refers to what end of both the coding/template strands?

Answer 22

3’

Question 23

How many bases upstream from the first transcribed base is the TATA box?

Answer 23

25 bp
located at (-25)

Question 24

Posttranscriptional modifications include:

Answer 24

5’ cap (7-methylguanylate triphosphate)

3’ poly-A tail (polyadenosyl)

Question 25

Splicing is accomplished by the splicesome which contains what two molecules?

Answer 25

SnRNA (small nuclear RNA) and snRNPs (small nuclear ribocucleoproteins)

Question 26

Lariat

Answer 26

name given to the excised noncoding regions of hnRNA

Question 27

What function does the 5’ cap serve?

Answer 27

Recognized by the ribosome as the binding site and protects from degradation

Question 28

What function does the poly-A tail serve?

Answer 28

Protects mRNA from the instant degradation it encounters as soon as it exits the nucleus … the longer the poly-A tail the more time the mRNA will survive before it is digested by the cytoplasm