Question

About 60% of the base pairs in a human DNA molecule are AT. If the human genome has 3.2 billion base pairs of DNA, about how many times will the following restriction sites be present?

a. BamHI (restriction site = 5'—GGATCC—3')
b. EcoRI (restriction site = 5'—GAATTC—3')
c. HaeIII (restriction site = 5'—GGCC—3')

Answer 1

The human genome consists of about 3.2 billion base pairs of DNA. The restriction sites for BamHI, EcoRI, and HaeIII will be present approximately 1.92 billion times each.

Step-by-step explanation:

The human genome consists of about 3 billion base pairs of DNA. Given that about 60% of the base pairs are AT, we can calculate the number of times the restriction sites will be present.

a. The restriction site for BamHI is 5'—GGATCC—3'. Since this site contains two A-T base pairs out of the total 6 base pairs, we can calculate the number of times it will appear by multiplying 60% (the percentage of AT base pairs) by 3.2 billion (the total number of base pairs): 0.6 * 3.2 billion = 1.92 billion.

b. The restriction site for EcoRI is 5'—GAATTC—3'. This site contains three A-T base pairs out of the total 6 base pairs. So, we can calculate the number of times it will appear by multiplying 60% by 3.2 billion: 0.6 * 3.2 billion = 1.92 billion.

c. The restriction site for HaeIII is 5'—GGCC—3'. This site contains two A-T base pairs out of the total 4 base pairs. So, we can calculate the number of times it will appear by multiplying 60% by 3.2 billion: 0.6 * 3.2 billion = 1.92 billion.