Deck 6: Genetic Analysis and Mapping in Bacteria and Bacteriophages

Question 1

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

Answer 1

C

Question 2

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 2

A

Question 3

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

Answer 3

A

Question 4

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

Question 5

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

Question 6

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 7

How does an auxotroph differ from a prototroph?

Question 8

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 9

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 10

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 11

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

Question 12

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

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

What are prototrophs?

Question 15

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

Question 16

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

Question 17

Distinguish between F⁺ and F⁻ bacteria.

Question 18

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

Question 19

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 20

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

Question 21

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 22

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

Question 23

What is meant by the term cotransformation?

Question 24

What is a bacteriophage?

Question 25

What is a merozygote?

Question 26

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

Question 27

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

Question 28

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

Question 29

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

Question 30

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

Question 31

Name three forms of recombination in bacteria.

Question 32

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

Question 33

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

Question 34

What are the roles of the recBCD genes?

Question 35

Compare and contrast bacteriophage lysis and lysogeny.

Question 36

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

Question 37

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 38

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 39

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

Question 40

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

Question 41

Lysogeny is most likely associated with transduction.

Question 42

A plaque is a substance that causes mutation in bacteria.

Question 43

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

Question 44

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

Question 45

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

Question 46

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

Question 47

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

Question 48

Lysogeny is a process that occurs during transformation and conjugation.

Question 49

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

Question 50

R plasmids often contain genes for antibody production.