Bacteriophage Genetics Practice Problems

The results of complementation tests of six deletion mutants of the bacteriophage are given below, where + indicates that recombinants were formed.

Determine the number of genes represented by these mutations.

Four point mutations are tested in paired crosses with five deletion mutations for their ability to yield wild-type recombinants and the results for the same are provided below. 

Determine the relative order of the point mutations.

Genetic complementation of two lysis-defective phage mutants occurs when:

The phage DNA that has been integrated into the host chromosome is termed the  _________.

The process by which a bacteriophage is able to transfer only specific parts of a bacterial chromosome is called ____________.

Four fruit fly mutants (A, B, C, and D) were studied for their ability to produce a certain eye pigment. The mutants are known to result from point mutations. The following table shows the results of the complementation tests between the mutants:

Gene-mapping information identifies mutations B and D as the flanking markers in this group of genes. Which one of the following could be a possible order of mutations in the region of the chromosome?

Genetic complementation is a phenomenon in which two individuals with ___________ that affect the  __________ can combine their genetic material to restore the _____________ phenotype.

A group of four mutant bacteria (P, Q, R, and S) was studied for their ability to produce a certain protein. The mutants are known to result from different types of mutations. The following table shows the results of the complementation tests between the mutants: 

A new mutant, designated T, fails to complement mutants P, Q, and R but complements mutant S. Wild-type recombinants form between mutant T and mutations Q and R, but not between T and P. What kind of mutation is seen in mutant T?  

A group of four mutant E. coli bacteria (A, B, C, and D) was studied for their ability to produce a certain enzyme. The mutants are known to result from point mutations. A new mutant, designated E, fails to complement mutant B. Wild-type recombinants form between mutant E and mutants A, C, and D. Which of the following statement is correct regarding E?

A group of four fruit fly mutants (X, Y, Z, and W) was studied for their wing development. The mutants are known to result from point mutations. The following table shows the results of the complementation tests between the mutants: 

In the experiment, researchers observed wild-type growth resulting from recombination in coinfections identified as failures to complement (-) in the table. How do the researchers distinguish between wild-type growth resulting from complementation and wild-type growth due to recombination? 

A group of four fruit fly mutants (X, Y, Z, and W) was studied for their wing development. Mutant Y fails to complement mutant Z while wild-type recombinants form between mutant W and mutant X. Which of the following groups of mutants have mutations in the same gene?

In plaque assay, plaques are counted to identify the titer of the original stock sample which is usually reported as:

A single bacteriophage produces 50 viable viruses upon infecting a single E. coli that is present on a bacterial lawn. Identify the total number of bacteriophages that one will observe on a single plaque if, in total, three lytic cycles occur.

According to Benzer, the capability of two mutants in combination to restore the wild-type function is called:

The following are the five steps in the T4 bacteriophage's life cycle. However, the order is incorrect; therefore, determine the correct order.
1. The phage DNA is replicated, followed by the synthesis of protein components.
2. The phage is adsorbed to the bacterial host cell.
3. The phage DNA is injected and the host DNA is degraded.
4. Mature phages are assembled.
5. The host cell is lysed, leading to the release of phages.

In mapping experiments, what does the frequency of recombination imply?

The following are the laboratory techniques used in the recombinational analysis except:

A bacterial culture was infected with two strains of a virus. One strain was minute (m), turbid (tu) and acriflavin-resistant (a), while the other one was wildtype for all the three genes. The resulting 10000 plaques were distributed among the genotypes listed below.

m tu a = 4000
+ + +   = 3900
m + +  =   800
+ tu a  =   720
+ tu +  =   200
m + a  =   200
+ + a   =      80
m tu + =    100

Identify the order of genes.

Which of the following is the end result of Benzer's work?

In the recombination testing, the number of resulting recombinants is 3 x 10⁵ / mL. If the total number of progeny is 12 x 10⁸ / mL, what is the frequency of recombination between the two mutants?

Which of the following is the main purpose of the serial dilution technique?

The development of resistance among E. coli in the absence of stimulus such as bacteriophage T1 is called:

Which of the following phages remains inside the host for a period of time without lysing and killing it?

The uptake of DNA from the external environment by a bacterial cell is called _______.

What is the difference between the rII mutant phages and the wild-type phages?

The transfer of genetic material from parent to offspring is referred to as ______. However, the transfer of genetic material from one bacterium to another is called _______.

Which of the following is counted in plaque assay?

Identify the inaccurate statement concerning the bacteriophage complementation test.

Which of the following recombinants do you anticipate to see when two virus strains with genotypes h⁺r and hr⁺ infect a bacterial culture?