Lecture 16: Gene Expression - Transcription

Question 1

What is gene expression?

Answer 1

The process by which information from a gene is used to synthesis functional gene products

Question 2

What are examples of functional gene products?

Answer 2

• Protein

- Non-coding RNA

Question 3

What is a gene?

Answer 3

A defined sequence of DNA that produces a type of RNA molecule that has some function

Question 4

What might a gene be responsible for?

Answer 4

The regulation of RNA synthesis

Question 5

What is transcription?

Answer 5

DNA-dependant RNA synthesis

Question 6

What catalyses transcription?

Answer 6

RNA polymerase

Question 7

What type of RNA is made during transcription?

Answer 7

mRNA

Question 8

How does RNA polymerase synthesise mRNA?

Answer 8

By catalysing the formation of phosphodiester bonds between ribonucleotides

Question 9

What does RNA polymerase do during transcription of then catalyse the formation of bonds?

Answer 9

Selects the correct nucleotides to incorporate into mRNA based on the sequence of the DNA being transcribed

Question 10

What are complementary DNA strands?

Answer 10

Two strands running antiparallel

Question 11

What are complementary sequences made of?

Answer 11

They are made of one coding strand and one template strand

Question 12

What direction does the coding strand run?

Answer 12

5’ -> 3’

Question 13

What direction does the template strand runs in?

Answer 13

3’ -> 5’

Question 14

What is mRNA transcribed from?

Answer 14

The DNA template strand

Question 15

What regulates initiation?

Answer 15

Specific DNA sequences

Question 16

What do transcription factors bind to during initiation?

Answer 16

They bind to the TATA box and other regions of the promoter

Question 17

What does RNA polymerase II do during initiation?

Answer 17

binds forming a transcription initiation complex with transcription factors

Question 18

After DNA strands seperate during initiation what do DNA polymerase II do?

Answer 18

start synthesising mRNA without the need of the a primer

Question 19

What does the RNA polymerase II do during elongation?

Answer 19

It starts to insert complementary RNA nucleotides in the 5’ -> 3’ direction

Question 20

Where does transcription occur?

Answer 20

In the nucleus

Question 21

Where does translation occur?

Answer 21

In the cytoplasm

Question 22

What are introns?

Answer 22

Non-coding regions

Question 23

What are exons?

Answer 23

Coding regions

Question 24

What do 5’ UnTranslated Regions (UTR’s) facilitate?

Answer 24

The addition of of the 5’ G cap

Question 25

What do 3’ UnTranslated Regions (UTR’s) facilitate?

Answer 25

The addition of the polyA tail

Question 26

What does a poly-A tail do?

Answer 26

It prevents mRNA degeneration and facilitate mRNA export from the nucleus