Bacterial Genetics

Question 1

Transformation

Answer 1

Ability to take up naked DNA from environment. Seen in P. pneumoniae, H. influenzae type B and Neisseria (SHiN). Any DNA can be used.
Adding deoxyribonuclease to environment will degrade naked DNA in medium –> no transformation seen

Question 2

Conjugation F+ x F-

Answer 2

F+ plasmid contains genes required for sex pilus and conjugation. Bacteria without this plasmid are termed F-. Plasmid (dsDNA) is replicated and transferred through pilus from F+ cell. No transfer of chromosomal genes.

Question 3

Conjugation Hfr x F-

Answer 3

F+ plasmid can become incorporated into bacterial chromosomal DNA, termed high-frequency recombination (Hfr) cell. Replication of incorporated plasmid DNA may include some flanking chromosomal DNA. Transfer of plasmid and chromosomal genes.

Question 4

Transposition

Answer 4

Segment of DNA that can “jump” from one location to another, can transfer genes from plasmid to chromosome and vice versa. When excision occurs, may include some flanking chromosomal DNA, which can be incorporated into a plasmid and transferred to another bacterium

Question 5

Transduction - Generalized

Answer 5

A packaging event. Lytic phage infects bacterium, leading to cleavage of bacterial DNA. Parts of bacterial chromosomal DNA may become packaged in viral capsid. Phage infects another bacterium, transferring these genes.

Question 6

Transduction - Specialized

Answer 6

An excision event. Lysogenic phage infects bacterium; viral DNA incorporates into bacterial chromosome. When phage DNA is excised, flanking bacterial genes may be excised with it. DNA is packaged into phage viral capsid and can infect another bacterium.

Question 7

Lysogeny is seen in what 5 toxins

Answer 7

Shiga like toxin
Botulinum toxin
Cholera toxin
Diphtheria toxin
Erythrogenic toxin of strep pyo