Gene Expression

Question 1

process of transcription

Answer 1

the synthesis of a single stranded RNA based on base-pairing with a single stranded DNA

Question 2

process of translation

Answer 2

the production of a polypeptide based on an RNA nucleotide sequence

Question 3

where does transcription occur in the cell?

Answer 3

nucleus

Question 4

where does translation occur in the cell?

Answer 4

cytoplasm

Question 5

mRNA vs tRNA vs rRNA

Answer 5

mRNA (messenger)= encodes a polypeptide and only RNA to get translated
tRNA (transfer) = carries AAs to ribosome
rRNA (ribosomal) = part of ribosome structure

Question 6

what is the role of the promoter in transcription?

Answer 6

The is a non-transcribed region of a gene. The sigma factor binds to the promoter, then facilitates the binding of RNA pol in proks

In Euks –> promoters recruit RNA pol by binding to basal TFs

Question 7

Coding vs template strand of DNA

Answer 7

coding strand matches mRNA (but w/out Us)
coding strand (ATG)–> template strand (TAC) –> mRNA (AUG)

Question 8

steps of translation initiation

Answer 8

1. small subunit and initiator tRNA bind to 5’ end of mRNA
2. Scanning begins for start codon AUG
3. large subunit binds to small subunit

Question 9

steps of elongation

Answer 9

1. charges tRNA enters at A site of ribosome
2. a polypeptide bond is created between the AA in the A and P sites
3. the bond is broken between the tRNA-aa in the P site
4. the ribosome translocates toward the 3’ end of mRNA

Question 10

steps of termination

Answer 10

release factors mimic shape of tRNA and bind, causing termination

Question 11

anticodon

Answer 11

a codon at one end of a tRNA molecule that is complementary to a mRNA sequence

Question 12

silent mutations

Answer 12

does not change AA seq

Question 13

nonsense mutations

Answer 13

change in nucleotide that results in early stop codon

Question 14

missense mutations

Answer 14

change in nucleotide that changes AA specified