Lecture 11 - Bacterial transcription

Question 1

What are the 2 levels of controlling gene expression?

Answer 1

Transcription

Translation

Question 2

What is the non-template strand also known as?

Answer 2

‘sense’ strand

Question 3

What is template strand also known as?

Answer 3

‘antisense’ strand

Question 4

What is the difference with DNA replication and RNA synthesis?

Answer 4

Uracil substitutes for Thymine

Question 5

Why is uracil not found in DNA?>

Answer 5

Cytosine can undergo spontaneous deamination to produce uracil

Spontaneous deamination - looses amino group, replaced by oxygen forming uracil

Question 6

How is uracil kept out of DNA?

Answer 6

Any uracil is removed by uracil-DNA glycosylase

Generates abasic site - breaks glyosidic bond

Removed and repaired by DNA polymerases

Question 7

What is an abasic site?

Answer 7

Backbone lacking base

Question 8

What are the 3 major classes of bacterial DNA?

Answer 8

mRNA - encodes proteins

rRNA - role in protein synthesis

tRNA - adaptors between mRNA and amino acids

Question 9

How many RNA polymerases synthesize the 3 classes of RNA molecules in bacteria?

Answer 9

One