Session 8-Gene Expression

Question 1

What three things does the process of making a polynucleotide or polypeptide need?

Answer 1

Enzyme
Activated substrates
Template

Question 2

What is the:
Enzyme?
Activated substrate?
Template?
For DNA?

Answer 2

DNA polymerase
dNTPs
DNA

Question 3

What are the names of the three stages in making a polynucleotide or polypeptide?

Answer 3

Initiation
Elongation
Termination

Question 4

What is the:
Enzyme?
Activated substrate?
Template?
For making RNA?

Answer 4

RNA polymerase
NTPs
DNA

Question 5

What is the process of making RNA called?

Answer 5

Transcription

Question 6

What is the:
Enzyme?
Activate substrate?
Template?
For making a polypeptide?

Answer 6

Ribosome
AA
mRNA

Question 7

In transcription, what is involved in the initiation stage? (3)

Answer 7

Promoter recognition
Transcription initiation factors
RNA polymerase

Question 8

Why is a TATA box important?

Answer 8

Transcription factor binding to a TATA box sets the direction of transcription

Question 9

What happens in elongation in transcription?

Answer 9

5’ to 3’ chain growth

Question 10

Which two methods protect mRNA against degradation?

Answer 10

Capping

Tailing or polyadenylation

Question 11

What happens in capping?

Answer 11

A 5’ to 5’ linkage is created to provide protection against degradation

Question 12

What happens in tailing or polyadenylation?

Answer 12

Occurs at the 3’ end of the chain (polyA tail)

Question 13

Why are there methods to prevent mRNA degradation?

Answer 13

Because RNA is unstable and is always degrading so it needs to be controlled

Question 14

What is splicing?

Answer 14

Occurs in the middle of the mRNA strand and involves the removal of introns and is sequence dependent

Question 15

What are the 5 different types of RNA?

Answer 15

rRNA
mRNA
tRNA
miRNA
Noncoding RNA

Question 16

Which RNA polymerase is used to make rRNA?

Answer 16

RNA polymerase I

Question 17

Which RNA polymerase is used to make mRNA?

Answer 17

RNA polymerase II

Question 18

Which RNA polymerase is used to make tRNA?

Answer 18

RNA polymerase III

Question 19

True or false: every transcription starts with AUG codon so every protein starts with methionine

Answer 19

TRUE

Question 20

What are the three termination codons?

Answer 20

UAA
UAG
UGA

Question 21

What is inosine?

Answer 21

Base in tRNA anticodons which can read U, C and A in the 3rd position

Question 22

What is a wobble base?

Answer 22

Wobble base pairs do not follow the normal base pair rules:
G-U
I-U
I-A
I-C

Question 23

What happens in initiation of translation?

Answer 23

AUG codon recognition
Special methionyl tRNA
Ribosome

Question 24

What happens in elongation in translation?

Answer 24

N to C chain growths
Aminoacyl tRNAs - A site is the point of entry for aminoacyl tRNA (except for first aminoacyl tRNA which enters at P site)
P site is where peptidyl tRNA is formed in ribosome

Question 25

What is aminoacyl tRNA?

Answer 25

tRNA to which AA is chemically bonded and delivers AA to ribosome for incorporation into polypeptide chain that is being produced

Question 26

What happens in termination of translation?

Answer 26

Stop codons are identified

Question 27

What are the subunits found in eukaryotic ribosomes?

Answer 27

40S and 60S subunits, which make up 80S

Question 28

What are the subunits found in prokaryotic ribosomes?

Answer 28

50S and 30S which make up a 70S ribosome

Question 29

What is a TATA box?

Answer 29

DNA sequence that indicates where a genetic sequence is read and decoded. It is a type of promoter sequence, which specifies to other molecules where transcription begins