Question

The introductory passage describes the way in which Vibrio cholerae bacteria obtain genes from their prey. Based on the information in the introductory passage and in the chapter, what type of gene transfer is this?
a. binary fission

b. transduction

c. conjugation

d. transformation

When new genetic material enters a bacterial cell through conjugation, transformation, or transduction, a merodiploid cell can be formed. Does this happen with the V. cholerae bacteria?

a. Yes, it produces temporary merodiploid cells between the time the genetic material enters the cell and the time that recombination occurs.
b. No, it cannot produce merodiploid cells because bacterial cells must always be haploid.
c. No, it cannot produce merodiploid cells because merodiploid cells can be produced only when entire genomes enter cells.
d. Yes, it produces permanent merodiploid cells because the newly introduced DNA has a replication origin.
e. Yes, it can, but only very briefly because the new genetic material is integrated back into the chromosome instead of undergoing recombination.

Answer 1

Answer:

1. The bacterium Vibrio cholerae obtains genes from its prey, a genetic transfer that occurs through the mechanism of transformation (option d).

2.  In the V. cholerae bacterium, the acquisition of new genetic material involves the production of temporary merodiploid cells between the time the genetic material enters the cell and the time when recombination occurs (option a).

Explanation:

1. In pathogenic bacteria such as Vibrio cholerae the introduction of genetic material into their genome produces structural and functional changes that promote their ability to cause disease.

In this case, the incorporation of genes by transformation leads to morphological change, development of colonization factors and strengthening of the toxin that V. cholerae produces.

2. Bacteria are prokaryotic cells whose chromosome charge is haploid, with the ability to have a single allele in the gene that determines a trait, and not in allele pairs, as is the case in eukaryotic cells.

The addition of external genetic material results in the bacterium having two alleles for a gene at any given time, which is called a partial diploid or merodiploid cell.

Once V. cholerae acquires new genetic material it becomes a merodiploid cell while genetic recombination occurs.