Deck 6: Genetic Analysis and Mapping in Bacteria and Bacteriophages

Question 1

What is a form of recombination in bacteria that involves the F plasmid?

Answer 1

conjugation

Question 2

A bacteriophage that is capable of entering either a lytic or lysogenic cycle is called a(n) ________.

A) temperate bacteriophage
B) virulent bacteriophage
C) plasmid
D) episome
E) plaque-forming unit

Answer 2

A

Question 3

Max Delbrück presented the first evidence that bacteria are capable of spontaneous mutation. What is the name of the test that Delbrück used to demonstrate this phenomenon?

A) fluctuation test
B) logarithmic test
C) lag test
D) prototrophic test
E) auxotrophic test

Answer 3

A

Question 4

Name two forms of recombination in bacteria.

A) lytic and lysogenic
B) auxotrophic and prototrophic
C) conjugation and transduction
D) mixed and generalized
E) insertion and replication

Question 5

Temperate phages are those that can enter either the ________ or ________ cycle.

A) lytic; lysogenic
B) virulent; avirulent
C) functional; nonfunctional
D) former; nonformer
E) complementing; competing

Question 6

Transduction is a form of recombination in bacteria that involves ________.

A) 5-bromouracil
B) plasmids
C) bacteriophages
D) fertility factors
E) physical contact between the bacteria involved

Question 7

Bacteriophages engage in two interactive cycles with bacteria. What are these cycles?

A) lytic and lysogenic
B) insertion and replication
C) auxotrophic and prototrophic
D) heteroduplex and homoduplex
E) negative and positive

Question 8

Name the typical phases of the bacterial growth cycle in liquid culture medium.

Question 9

Explain the composition and use of minimal medium in the study of bacterial genetics.

Question 10

How does an auxotroph differ from a prototroph?

Question 11

Name the general category into which double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R would fall.

A) capsid
B) r-determinant
C) plaque
D) partial diploid
E) plasmid

Question 12

Distinguish between F⁺ and F^- bacteria.

Question 13

The clearing made by bacteriophages in a "lawn" of bacteria on an agar plate is called a ________.

A) clear zone
B) lysogenic zone
C) prophage
D) plaque
E) host range

Question 14

Assume that the gene trpA in an auxotrophic strain of E. coli is located at 27 minutes, whereas the gene pyrE is located at 81 minutes.
a) How are minutes arrived at in this context?
b) Present an experimental scheme that would allow you to convert one of the auxotrophic strains to a prototrophic strain.

Question 15

Describe how different strains of E. coli can reveal different linkage arrangements of genes in Hfr crosses.

Question 16

What is the role of the F factor in bacterial recombination?

Question 17

In general, what two methods are used to grow bacteria in the laboratory?

Question 18

What are prototrophs?

Question 19

In what way was the interrupted mating technique used to generate a genetic map in E. coli based on time?

Question 20

Jacob, Wollman, and others developed a linkage map of E. coli that is based on time. What form of recombination is involved in generating a linkage map based on time?

Question 21

Bacteriophages that cannot undergo lysogeny but can infect bacteria are called ________.

Question 22

What are the roles of the recBCD genes?

Question 23

Lysogeny is an important phenomenon in bacteria and phages. Briefly describe lysogeny (using labeled diagrams if helpful).

Question 24

Assume that one counted 67 plaques on a bacterial plate where 0.1 ml of a 10^-5 dilution of phage was added to bacterial culture. What is the initial concentration of the undiluted phage?

Question 25

What experimental observation demonstrated that genes are involved in the integration of foreign DNA into the bacterial chromosome?

Question 26

In a bacterial cross in which the donor (Hfr) is a⁺b⁺ and the recipient strain (F^-) is a^-b^-, it is expected that recombinant bacteria will all be a⁺b^+.

Question 27

A form of bacterial recombination that involves a viral intermediate is called ________.

Question 28

Name three forms of recombination in bacteria.

Question 29

Bacteria that are in a particular physiological state to become transformed are called ________.

Question 30

What is a significant difference between a lytic and a lysogenic cycle?

Question 31

What is a bacteriophage?

Question 32

What is the consequence of a mutation in the recA gene in bacteria?

Question 33

What is meant by the term cotransformation?

Question 34

Present the general structural features of a plasmid and give an example.

Question 35

If two different auxotrophic strains are placed in a liquid medium culture tube, prototrophic strains can sometimes be subsequently recovered. Name several mechanisms by which this is possible.

Question 36

Explain what is meant by the term heteroduplex in the context of bacterial transformation.

Question 37

When a bacteriophage genome incorporates itself into the chromosome of the host, that phage genome is referred to as a(n) ________.

Question 38

Compare and contrast bacteriophage lysis and lysogeny.

Question 39

What is a merozygote?

Question 40

Name the term used to describe the phenomenon in which a bacteriophage genome incorporates its genome into the chromosome of the host.

Question 41

Cotransduction of genes is an indication that the genes are linked.

Question 42

The "interrupted mating technique" provides a genetic map in Drosophila.

Question 43

R plasmids often contain genes for antibody production.

Question 44

Lysogeny is a process that occurs during transformation and conjugation.

Question 45

Lysogeny is most likely associated with transduction.

Question 46

A symbiotic relationship between a phage and a bacterium apparently occurs in the process of lysogeny.

Question 47

An Hfr cell can initiate chromosome transfer from one E. coli to another.

Question 48

To produce recombinants in bacteria, one crossover is better than two.

Question 49

Viral mutations and variants are often categorized by changes in host range and/or plaque morphology.

Question 50

A plaque is a substance that causes mutation in bacteria.