Deck 6: Bacterial and Viral Genetic Systems

Question 1

In a gene mapping experiment,DNA from a strain that is gal⁺ pro⁺ lac⁺ is transformed into an E.coli that is gal⁻ pro⁻ lac⁻.Some resulting transformants are gal⁺ lac⁺ and some are pro⁺ lac⁺,but no transformants are gal⁺ pro⁺.Which gene is in the middle?

A)gal
B)lac
C)pro
D)cannot be determined

Answer 1

B
lac

Question 2

Which is NOT an advantage of using bacteria for genetic studies?

A)Haploid genomes allow all mutations to be expressed directly.
B)Bacteria are of medical importance.
C)Bacteria have small genomes.
D)Asexual reproduction makes it easier to isolate genetically pure strains.
E)all of the above

Answer 2

E
a ll of the above

Question 3

The viral enzyme reverse transcriptase is used to

A)convert the viral DNA genome into a new DNA genome.
B)convert the viral RNA genome into a DNA genome.
C)digest the host cell.
D)allow the virus to enter the host cell.

Answer 3

B
convert the viral RNA genome into a DNA genome.

Question 4

Genetic exchange in bacteria is different from eukaryotic diploid genetic exchange in which way?

A)In bacteria,donated genetic material that is not recombined persists.
B)In bacteria,genetic exchange results in diploid progeny.
C)In bacteria,genetic exchange is NOT coupled with reproduction.
D)all of the above

Question 5

Barnard Davis's U-shaped tube experiment indicated that bacterial genetic exchange requires

A)the exchange of liquid medium between the two sides of the tube.
B)direct contact between the two bacteria.
C)mutations to be reverted to wild type.
D)none of the above

Question 6

Which is NOT true of plasmids?

A)They usually carry essential genes for bacterial survival.
B)Their replication is independent of the chromosomal DNA.
C)They are used extensively in genetic engineering.
D)They can provide antibiotic resistance.
E)They consist of double-stranded DNA.

Question 7

In mapping genes using transduction,genes that are _______ will NOT be cotransduced.

A)far apart
B)mutated
C)wild type
E)close together

Question 8

During which bacteriophage life cycle are new phages released from the bacteria by digesting the host cell?

A)lysogenic
B)lytic
C)both
D)neither

Question 9

Which of the following F factors can transfer chromosomal DNA?

A)F⁺
B)F⁻
C)F′
D)Hfr
E)F⁻ and Hfr

Question 10

If you were mapping bacterial genes and let the conjugation go for 100 minutes,approximately what percentage of the genome would be transferred?

A)0%
B)25%
C)50%
D)755
E)100%