Deck 8: Genetic Analysis and Mapping in Bacteria and Bactierophages

Question 1

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

Answer 1

The interrupted mating technique showed that genes were passed in a linear
fashion from the Hfr bacterial strain to an F - strain. By interrupting the mating tube, it could be determined when (in minutes) genes were transferred.

Question 2

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

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

Answer 2

A

Question 3

Name two forms of recombination in bacteria.

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

Answer 3

A

Question 4

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 5

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

Question 6

How does an auxotroph differ from a prototroph?

Question 7

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

Question 8

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

Question 9

Transduction is a form of recombination in bacteria that involves

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

Question 10

Distinguish between F+ and F - bacteria.

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) plaque
C) partial diploid
D) r -determinant
E) plasmid

Question 12

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. How are minutes arrived at in the
context of gene mapping in bacteria?

Question 13

What is a merozygote?

Question 14

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

Question 15

Temperate phages are those that can enter either the or

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

Question 16

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

Question 17

What are prototrophs?

Question 18

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

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

Question 19

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

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

Question 20

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

Question 21

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

Question 22

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

Question 23

Compare and contrast bacteriophage lysis and lysogeny.

Question 24

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

Question 25

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

Question 26

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

Question 27

What are the roles of the recBCD genes?

Question 28

What is a bacteriophage?

Question 29

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

Question 30

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

Question 31

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

Question 32

What is meant by the term cotransformation?

Question 33

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

Question 34

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 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

Lysogeny is an important phenomenon in bacteria and phages. Briefly describe lysogeny.

Question 37

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 38

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

Question 39

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

Question 40

What term is used to describe the phenomenon in which a bacteriophage genome incorporates its genome into the chromosome of the host?

Question 41

Lysogeny is a process that occurs during transformation and conjugation.

Question 42

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

Question 43

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

Question 44

Lysogeny is most likely associated with transduction.

Question 45

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

Question 46

R plasmids often contain genes for antibody production.

Question 47

A plaque is a substance that causes mutation in bacteria.