Unit 2 - 14. Bacterial & Viral Genetics

Question 1

plasmid

Answer 1

• a circular double-stranded DNA molecule in bacteria which is located outside of the main chromosome
• can replicate independently of the main chromosome
• influences important bacterial functions such as resistance to antibiotics
• may exist as one copy or multiple copies per cell
  Examples:
  R plasmid = carry genes for resistance to various antibodies
  F plasmid = responsible for DNA transfer during conjugation

Question 2

bacteriophage

Answer 2

• a virus that infects bacterial cells

- commonly called a phage

Question 3

Transposon

Answer 3

• gene that moves from one DNA molecule to another within the same cell or from one site on a DNA molecule to another site on the same molecule
• contains insertion sequences (IS) on either end

Question 4

Transformation

Answer 4

• DNA fragments picked up by a recipient bacterium cell & incorporates it into the cell genome
• same species and needs to be competent

Question 5

Transduction

Answer 5

• process by which a bacteriophage carriers genetic information from one bacterial cell (donor cell) to another (recipient cell)

Question 6

Conjugation

Answer 6

• DNA transferred from one bacterial cell (donor cell/male cell) to another (recipient/female cell) via sex pillus and plasmid

Question 7

Mapping Bacterial Genes: Transformation

Answer 7

• only genes that are close together will be carried on the same molecule of transforming DNA (due to DNA fragments)

Question 8

Mapping Bacterial Genes: Transduction

Answer 8

• only genes close together can be transferred by phage because not all of the bacterial gene can fit into phage

Question 9

Mapping Bacterial Genes: Conjugation

Answer 9

• interrupt mating at different time intervals and look at phenotype of recipient

Question 10

4 commonly used bacterial mutants

Answer 10

1. Antibiotic resistant mutants
2. Nutritional mutants
3. Carbon source mutants
4. Temperature sensitive mutants

Question 11

1. Antibiotic resistant mutants

Answer 11

• mutants that are able to grow in the presence of an antibiotic that would kill bacteria without this mutation

Question 12

2. Nutritional mutants

Answer 12

• mutants that are unable to synthesize an essential nutrient
• only grow in medium with nutrient

Question 13

3. Carbon source mutants

Answer 13

• cannot use a particular substance as a source of energy/carbon

Question 14

4. Temperature sensitive mutants

Answer 14

• will grow at one temperature but not at another temperature