A person has the blood group AB, what determines this blood group?
a) different alleles on different chromosomes
b) different alleles on the same chromosomes
c) the same alleles on different chromosomes
d) the same allele on the same chromosomes
I thought that the answer should be B, but the correct answer is A. Why is it B and not A??
Chromosomes typically come in pairs. Would the other chromosome in the pair be considered the same (because of its designation) or different?
Actually, the correct answer is A, not B. A person's blood group is determined by different alleles on different chromosomes. Let's break this down to better understand why.
The ABO blood group system is determined by the presence or absence of certain antigens (proteins) on the surface of red blood cells. There are three different alleles that can determine blood type: A, B, and O.
A person with blood type AB has both A and B antigens present on their red blood cells. This means they must have inherited one A allele from one parent and one B allele from the other parent. Alleles are alternate forms of a gene, and we inherit one allele for each gene from each parent.
The A allele and B allele are located on different chromosomes. In humans, we have 23 pairs of chromosomes, and the A and B alleles are on separate chromosomes, not on the same chromosome. Each parent contributes one chromosome to determine the alleles inherited.
So the correct answer is A) different alleles on different chromosomes, because blood type AB is determined by inheriting one A allele and one B allele located on separate chromosomes.