Unit 9- Bacterial and Viral Genetic Systems

Question 1

adv of using bacteria/viruses in genetic studies

Answer 1

1) reproduction is rapid
2) many progeny are produced
3) haploid genome allows all mutations to be expressed directly
4) asexual reproduction, simplifies the isolation of genetically pure strain
5) growth in lab is easy and requires little space
6) genomes are small
7) techniques are available for isolating and manipulating their genes
8) they have medical importance
9) they can be genetically engineered to produce substances of commercial value

Question 2

phototrophic

Answer 2

wild type

Question 3

ausotrophic

Answer 3

mutant type

Question 4

min medium

Answer 4

only required by phototrophic bacteria

Question 5

complete medium

Answer 5

all the substances, like amino acids, needed by bacteria to grow and reproduce
*including autotrophic bacteria

Question 6

selective medium

Answer 6

A medium that lacks
an essential nutrient

Question 7

plasmids

Answer 7

small, circular DNA molecules. Mostly non-essential genes but helps in some environs

Question 8

episomes

Answer 8

freely replicating plasmids
- F (fertility) factor

Question 9

conjugation

Answer 9

direct transfer of DNA from one bacterium to another
- direct transfer via connection tube (sex pilus) is 1 way traffic from donor to host

Question 10

transformation

Answer 10

bacterium takes up DNA (small fragments) from medium
- recomb takes place

Question 11

competent cells

Answer 11

cells that take up DNA

Question 12

transformants

Answer 12

cells that recieve genetic material

Question 13

cotransformation

Answer 13

2+ genes are transferred to host. (rate used for mapping: 2 genes are more likely to be transferred when close)

Question 14

transduction

Answer 14

bacterial viruses take DNA from one bacterium to another
* bacteriophages carry DNA
- usually between same/closely-related species
- generalized (any gene) or specialized (few genes)

Question 15

antibiotic resistance

Answer 15

due to R plasmids that can be transferred to any type of bacterium

Question 16

horizontal gene transfer

Answer 16

genes can be passed between indiv members of diff species by nonproductive mechanisms

Question 17

bacterial defense mechansisms

Answer 17

• restriction-modification systems
  -CRISPR- Cas systems
  -CRISPR ARRAY
  -CRISPR-CAS FUNCTION
  -PAM SEQUENCES

Question 18

retrovirus

Answer 18

RNA virus that has been integrated into the host genome

Question 19

reverse transcriptase

Answer 19

synthesizing DNA from RNA or DNA template

Question 20

virus

Answer 20

replicating structure (DNA/RNA) + protein coat

Question 21

bacteriophage

Answer 21

bacterial infection virus
- viruelent phages reproduced through lytic cycle kill host

Question 22

temperate phages

Answer 22

phage DNA integrates into bacterial chromosome, where it remains as inactive prophage

Question 23

cotransduction

Answer 23

only genes close together on gene are transferred together
(distance indicator)

Question 24

provirus

Answer 24

A viral genome
incorporated into the host chromosome