DNA Transcription

Question 1

This is the process by which information from a gene is used in the synthesis of a functional gene or product: protein or non coding RNA

a) transcription
b) translation
c) gene expression
d) DNA replication

Answer 1

Gene expression

Question 2

This states that genetic information only flows in one direction. (from DNA to RNA via transcription and from RNA to proteins via translation)

Answer 2

Central Dogma of Molecular Biology

Question 3

Why is the Central Dogma of Molecular Biology wrong?

Answer 3

Because RNA can be used to make new DNA
Because DNA can give rise to non-coding RNA (which does not code for a functional protein)

Genetic information doesn’t just go one way.

Question 4

This is an RNA molecule that does not give rise to a protein and has some other function

Answer 4

Non-coding RNA

Question 5

A defined region (sequence) of DNA that produces a type of RNA molecules that has some function

Answer 5

Gene

Question 6

What are 3 functions of a gene sequence?

Answer 6

Regulating synthesis of RNA
Produce RNA
Further process RNA

Question 7

This is a DNA-dependent RNA synthesis.

Answer 7

Transcription

Question 8

What is the enzyme used to catalyse transcription?

Answer 8

RNA polymerase

Question 9

How does RNA polymerase synthesise mRNA?

Answer 9

By catalysing the formation of phosphodiester bonds between ribonucleotides.

Question 10

mRNA is transcribed from which strand?

Answer 10

Template strand

Question 11

What is the template strand?

Answer 11

The DNA sequence that is to be transcribed. The strand that determines what base will be added complementary to it. Template strand is synthesised in 3’ to 5’ direction

Question 12

What is the coding strand?

Answer 12

The strand that RNA polymerase will add nucleotide bases to. Coding strand is synthesised in 5’ to 3’ direction.

Question 13

What are the 3 stages of Transcription?

Answer 13

Initiation, Elongation, Termination

Question 14

Initiation is regulated by specific DNA sequences. What is an example of this?

Answer 14

TATA box and promoter regions to initiate mRNA synthesis.

Question 15

Does transcription require a primer? Why/why not?

Answer 15

No it does not need a primer.

It has promoter regions that contain a TATA box that transcription factors will bind to for the RNA pol II to bind to and start transcription.

Question 16

What is the enzyme responsible for forming a transcriptional initiation complex? What does it bind to?

Answer 16

RNA polymerase II binds to transcription factors on the TATA box (in promoter regions)

Question 17

These are regions of the DNA sequence that can be transcribed but not translated.

They are involved in regulating gene expression.

Answer 17

Non-coding regions

Question 18

What happens if there are mutations in non-coding regions?

Answer 18

This results in disruption of normal gene expression

Question 19

This is a DNA segment that is recognised by RNA polymerase to initiate transcription.

Answer 19

Promoter regions

Question 20

These contain regulatory elements/sequences that influence on gene expression at transcriptional/translational level

Answer 20

UTRs/untranslated regions like 5’ UTR 3’UTR

Question 21

This facilitates the addition of Poly A tail

Answer 21

3’ UTR

Question 22

This facilitates the addition of 5’ G cap

Answer 22

5 ‘ UTR

Question 23

This prevents the degradation of mRNA and facilitates export of mRNA from nucleus to cytoplasm.

Answer 23

Poly A tail

Question 24

This is the process where introns are removed to form a full coding sequence using UTRs

Answer 24

Splicing

Question 25

Where does transcription occur in eukaryotes?

Answer 25

In the nucleus

Question 26

Where does transcription occur in prokaryotes?

Answer 26

In the cytoplasm

Question 27

Which parts of a gene are transcribed from DNA to mRNA?

Answer 27

Coding sequence + non-coding regions (like UTR)

Question 28

Which parts of a gene are translated from mRNA to proteins?

Answer 28

Coding sequence only