Which genotype produces O phenotype?

Prepare for the Leaving Cert Biology exam with our Genetics test! Use targeted study aids, hints, and explanations for each question to boost your confidence and success. Get exam-ready now!

Multiple Choice

Which genotype produces O phenotype?

Explanation:
In the ABO system, the presence of A or B antigens on red blood cells determines the phenotype. A and B alleles code for enzymes that modify the surface H antigen to become A or B antigens. The i allele is nonfunctional, so it doesn’t add any sugar to the H antigen. Therefore, only when both alleles are i do you end up with no A or B antigens on the cell surface, which gives the O phenotype. The other genotypes produce A or B antigens: two IA alleles make A, IA with i makes A, and two IB alleles make B.

In the ABO system, the presence of A or B antigens on red blood cells determines the phenotype. A and B alleles code for enzymes that modify the surface H antigen to become A or B antigens. The i allele is nonfunctional, so it doesn’t add any sugar to the H antigen. Therefore, only when both alleles are i do you end up with no A or B antigens on the cell surface, which gives the O phenotype. The other genotypes produce A or B antigens: two IA alleles make A, IA with i makes A, and two IB alleles make B.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy