Lecture 34: Microbial Genetics

Question 1

List 3 properties of bacterial genome:

Answer 1

• Typically a singular circular chromosome
• No nuclear membrane
• Small circular DNA molecules known as Plasmids

Question 2

What is the region called that the chromosome in a bacterial cell is confined to known as?

Answer 2

Nucleoid region

Question 3

What are 2 types of gene transfer amongst bacteria?

Answer 3

• Horizontal gene transfer

- Vertical gene transfer

Question 4

What is horizontal gene transfer?

Answer 4

Transferring genes from one organism directly to another

Question 5

What is vertical gene transfer?

Answer 5

Transferring genes from ‘parent’ to ‘offspring’

Question 6

What are the 3 types of horizontal gene transfer?

Answer 6

• Transformation
• Transduction
• Conjugation

Question 7

Outline the features of conjugation.

Answer 7

• Bacteria use a sex pilus, that attach to another bacteria

- plasmids unwind and are fed through the pilus to another bacteria

Question 8

Outline the features of transformation.

Answer 8

Naked DNA fragments find their way into another bacteria

Question 9

Outline the features of transduction.

Answer 9

Phage virus bind and inject their DNA into bacteria

Question 10

Outline the lytic cycle.

Answer 10

• Phage inserts its DNA
• replicates using the bacteria’s machinery
• Cell lyses releases newly assembled phages

Question 11

Outline the Lysogenic cycle.

Answer 11

• Phage DNA integrates with bacterial DNA

- Cell replication creates more bacteria containing bacterial chromosome