Regulation Of Gene Expression (week 13)

Question 1

What is the meaning of gene expression?

Answer 1

The process of information from a gene being used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype (final effect).

Question 2

A major method of gene expression in bacteria is?

Answer 2

The bacterial promoter
- polycistronic operon
- promoter
- initiation by a sigma factor
- RNAPol enabling or blocking

Question 3

What does the lac-i repressor bind to?

Answer 3

Lactose (techinically alo-lactose, an isomer of lactose)

Question 4

Phosphoryaltion mechanism

Answer 4

Signal -> phosporelay -> changes response in regulatory behaviours

Question 5

What is transcriptional regulation?

Answer 5

• Acts in the promoter reigon
• Acces of RNAPolymerase to the promoter
• Production of a transcript
• Sigma factors in RNAPol locate the binding spot

Question 6

What are sigma factors?

Answer 6

• They recognise motifs in the promoter sequence
• Different sigma factors will be present under different conditions and thus changes gene expression (eg. Ecoli under heat shock expresses new genes due to a change in sigma factor).

Question 7

What is the lac operon?

Answer 7

• Negative regulation in bacteria
  More info on page 33 of notes

Question 8

What is the method of regualtion of gene expression through chromatin (indirect)?

Answer 8

Histone spacing can be very close together or further apart - the looser chromatin is the more proteins that can access it. Thus is a TF.

Question 9

What is a method of inhibition of gene expression?

Answer 9

• Methylation of the DNA, locks in pattern of gene expression

Question 10

What is totipotency?

Answer 10

The ability of a cell to differentiate into any type of cell.