Answer:
Use the following information to answer the question.
A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest.
Analysis of the data obtained from two students each have two fragments, two students each have three fragments, and two students each have one only.
What does this demonstrate?
a. The two students who have two fragments have two restriction sites within this gene.
Step-by-step explanation:
As every enzyme, a restriction enzyme works by recognizing DNA sequence bonding shapes, it is called recognition site, wraping the DNA molecule and, causing a double stranded cut, so his restriction enzyme needs to be the same one that cut the gene, the enzyme recognizes specific sites in DNA, so the plasmid will have ends that will match the gene's ends.
Option b: the students with three fragments are said to have "fragile sites", is not correct as "common fragile sites" or CFSs are not determined only using a restriction enzyme, but by complex repeated sequences on DNA inbuilt traits, which lead to these perturbed, unstable, genomic structures.
Option c: each of these students is heterozygous for this gene, is not correct as heterozygous refers to a person inheriting two different alleles, 1/2 from the mother´s chromosomes and 1/2 from the father´s, through sexual reproduction for a specific trait, not only fragments.
Option d: each pair of students has a different gene for this function, is not correct as the sample was collected from the same site for each of the students.
Option e. the two students who have two fragments have one restriction site in this region, is not correct as the restriction enzymes cleave DNA at fixed positions at their recognition sequence, leading to the same reproducible fragments.