Gene Expression

Question 1

What enzymes are involved in DNA replication?

Answer 1

DNA polymerase
Ligase
Helicase

Question 2

What is the enzyme used in RNA transcription?

Answer 2

RNA polymerase

Question 3

What is the template used in RNA transcription?

Answer 3

DNA strand

Question 4

What are the 3 stages in RNA transcription?

Answer 4

Initiation
Elongation
Termination

Question 5

What is the enzyme used in RNA translation?

Answer 5

Ribsome

Question 6

What is the template used in RNA translation?

Answer 6

mRNA

Question 7

How is the DNA strand being read in DNA replication? How is being made?

Answer 7

It’s being read 3’ to 5’ and being made 5’ to 3’.

Question 8

When does termination occur in DNA replication?

Answer 8

When two replication forks meet.

Question 9

Explain the initiation of RNA transcription.

Answer 9

A promoter recognises specific sequence on the DNA strand called the TATAAA-box.

Question 10

In what direction is the DNA template during RNA transcription being read?

Answer 10

In 3’ to 5’. This means that the mRNA is complementary to the template strand and identical to the other strand.
The direction of how it is built is 5’ to 3’.

Question 11

What is RNA processing?

Answer 11

pre-mRNA needs to become mature mRNA which is going to be translated.

Question 12

What different steps are involved in RNA processing?

Answer 12

Capping
Tailing/Polyadenylation
Splicing

Question 13

What is capping?

Answer 13

At the 5’ end there is put on a 5’ cap. This is to protect against degradation.

Question 14

What is tailing or polyadenylation?

Answer 14

At the 3’ end there is polyadenylation tail. This is a lot of adenine put on.
This also protects against degradation.

Question 15

What is splicing?

Answer 15

This happens in the middle where introns are removed. This step is sequence dependent and is necessary because introns are not supposed to be coded for in translation.

Question 16

Are introns never translated in RNA translation?

Answer 16

Yes they can be if there is a mutation. Splicing is sequence dependent so it need precise splicing. If there is a mutation on an intron it might not be spliced off.

Question 17

What kind of ribosomes are found in eukaryotes? What subunits?

Answer 17

80s ribosomes with 40S + 60S subunits.

Question 18

How does initiation occur in translation?

Answer 18

First of the 40s subunit recognises the 5’Cap on the mRNA. It then starts to go through the mRNA. When it recognises the start codon AUG the 60s subunit is put on and the mRNA will start being read.

Question 19

How does termination occur in translation?

Answer 19

By triplet codons as well called stop codons. UAA, UAG and UGA.

Question 20

What is the wobble position of a tRNA and what does it do?

Answer 20

A base called in the wobble position is called wobble base. It allows the tRNA to recognise more than one codon.

Question 21

In what direction do amino acids grow?

Answer 21

In N to C.

Question 22

What is aminoacyl tRNA?

Answer 22

The tRNA that is needed for translation of the mRNA to produce an amino acid.

Question 23

What is an anticodon?

Answer 23

A specific sequence found on the tRNA which matches/recognises the codon on the mRNA.

Question 24

In what direction is the mRNA being read?

Answer 24

In 5’ to 3’.

Question 25

How does elongation work in translation?

Answer 25

Formation of peptide bonds with the help of peptide transferase. The amine group and the carboxyl group join to form a peptide bond and H2O is released.