Microbial genetics - 34

Question 1

What are 3 important properties of bacterial genome

Answer 1

Single circular chromosome
No nuclear membrane - Chromosome confined to nucleoid (specific region)
Plasmids - Self replicating DNA molecules in cytosol

Question 2

How was horizontal gene transfer discovered

Answer 2

Injected heat treated (dead) bacteria with lethal mutation and non mutated harmless from into subject. Host then died as a result of the harmful mutation being transferred to the live bacteria

Question 3

What are the 3 strategies of horizontal gene transfer

Answer 3

Transformation
Transduction
Conjugation

Question 4

Describe transformation gene transfer

Answer 4

Naked DNA from dead bacteria finds its way into live bacteria. It multiplies and creates the gene in new bacteria. (Possible as DNA is heat resistant)

Question 5

Describe conjugation gene transfer

Answer 5

Use of Sexual Pilus - attaches to another bacterial cell and unwinds circular strands moving them along the tube.

Question 6

Describe transduction gene transfer

Answer 6

When phage viruses use bacteria to reproduce sometimes they take up the bacteria’s genome (completely random mistake). They then inject this into another bacteria and it is reproduced.

Question 7

Briefly describe lytic replication

Answer 7

Phage DNA uses bacteria to reproduce itself

Question 8

Briefly describe lysogenic replication

Answer 8

Phage DNA integrates into bacteria (prophage) and is reproduced. Will sometimes randomly separate again and turn to lytic.