Question

In a culture of bacteria, there are some individuals that are unable to synthesize histidine. What is the best and most likely description of how these individuals differ from the other bacteria in the culture?
A) They differ in their phenotype but not in their genotype.
B) They don't differ in genotype or phenotype.
C) They differ in their genotype and in their phenotype.
D) They differ in their genotype but not in their phenotype.

Answer 1

Answer:

C) They differ in their genotype and in their phenotype.

Explanation:

Genotype refers to the genetic composition of an organism. It represents the gene and the respective alleles present in the genome of an organism. The genetic traits exhibited by organism due to the presence of a particular gene in its genome reflects the associated phenotype. Phenotype is the morphological expression of genotype.

The ability to synthesize histidine is a genetic trait. Bacteria not able to do so lack one or more genes that code the proteins involved in histidine biosynthesis. Here, the inability of histidine biosynthesis is the phenotype governed by the absence of the respective gene. Therefore, the bacteria unable to form histidine have different genotype and phenotype from the ones that can synthesize it.