Mechanisms of Gene Transfer

Question 1

4 DNA carriers/donors:

Answer 1

• Plasmids
• Transposons
• Phages
• Microbiome

Question 2

3 Transfer mechanisms:

Answer 2

• Conjugation
• Transformation
• Transduction

Question 3

What transfer mechanisms are used to transfer plasmids to other bacteria?

Answer 3

Conjugation, transformation, transduction

Question 4

Small genetic elements capable of mediating their own mvt from one chromosomal (or plasmid) location to another

Answer 4

Transposon

Question 5

Extrachromosomal, autonomously replicating circular DNA molecules

Answer 5

Plasmids

Question 6

Nickname for Class II transposition

Answer 6

Cut and Paste

Question 7

Plasmid-mediated process of DNA transfer from one cell to another

Answer 7

Conjugation

Question 8

What two things are required for bacterial conjugation?

Answer 8

1) cell-to-cell contact long enough for conjugation bridge to be built via sex pilus
2) Presence of conjugal plasmid capable of transfer replication

Question 9

What encodes the sex pili?

Answer 9

Conjugative plasmid in donor (male)

Question 10

Is the copy of the plasmid transferred to the female in bacterial conjugation single or double stranded?

Answer 10

Single - it is later converted to a circular duplex molecule in the recipient

Question 11

Cell lyses, free DNA fragments, DNA binds to bacterial cell surface, DNA enters recipient cell, DNA integrates into host chromosome by homologous recombination

Answer 11

Transformation

Question 12

Capsule exchange can occur through what type of transfer mechanism and commonly involves what species?

Answer 12

Transformation - pneumococci

Question 13

What types of genes are acquired in bacterial transformation that involve resistance to antibiotics?

Answer 13

• Genes that encode antibiotic binding proteins
• Genes that encode enzymes that inactivate antibiotics
• Genes that encode exporters of antibiotics

Question 14

Result of occasional packaging of host DNA during lytic infection and subsequent transfer to a recipient via phage injection

Answer 14

Transduction

Question 15

What types of phage receptors are present on bacterial surface?

Answer 15

• O-antigens
• Porins
• Flagella
• Pili

Question 16

What toxin genes are carried on bacteriophages? (ABCDE)

Answer 16

ShigA-like toxin
Botulinum toxin
Cholera toxin
Diphtherai toxin
Erythrogenic toxin (S pyogenes)