Multiple Choice
Approximately how much DNA is present in the nucleus of a human somatic cell during the G1 phase of the cell cycle?
4
views
7. DNA and Chromosome Structure
DNA Structure
Struggling with Genetics?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
In an agarose gel electrophoresis experiment analyzing DNA structure, which individual's sample would most likely show DNA fragments of approximately 470 bp and 330 bp after digestion with a restriction enzyme that cuts at a specific site within the DNA?
A
A heterozygous individual with one allele containing the restriction site and one allele lacking it
B
A homozygous individual with both alleles lacking the restriction site
C
An individual whose DNA was not digested with the restriction enzyme
D
A homozygous individual with both alleles containing the restriction site
Verified step by step guidance1
Understand that the restriction enzyme cuts DNA at a specific recognition site, producing fragments of predictable sizes if the site is present.
Recognize that a homozygous individual with both alleles containing the restriction site will produce fragments of the same sizes from both alleles, resulting in bands of identical length on the gel.
Know that a homozygous individual lacking the restriction site will have uncut DNA, so only one larger fragment (the full-length DNA) will appear on the gel.
Consider a heterozygous individual with one allele containing the restriction site and one allele lacking it; digestion will produce two different fragment sizes corresponding to the cut and uncut alleles, resulting in two distinct bands (e.g., 470 bp and 330 bp).
Conclude that the presence of two distinct fragment sizes after digestion indicates heterozygosity for the restriction site, which explains why the sample shows bands at approximately 470 bp and 330 bp.
Related Videos
Related Practice
