Question

EOC Biology STAAR Test Prep

Answer 1

Answer:

D. A, B, AB, or O

Explanation:

We can start by visualizing all the possible genotypes of the offspring by drawing a Punnett square, which is a visual representation of the different possible combinations of alleles:

Individual 1 = AO, Individual 2 = BO

     A   O

B  AB  BO

O  AO  OO

Here we can see that there are 4 possible genotypes: AB, BO, AO and OO based on the alleles of the parents. Now we can match the genotypes to phenotypes to answer the question:

A and B are codominant, meaning that both will be expressed equally if both are present. Therefore the genotype AB will result in an AB phenotype.

Next, since A and B are both dominant over O, they are the alleles that will be expressed in the phenotype if paired with an O. This means that the genotype AO will result in an A phenotype, and likewise, genotype BO will result in phenotype B.

Finally in the genotype OO, although O is a recessive allele, there are no dominant alleles here to mask them, therefore O is expressed in the phenotype.

Hence, from the genotypes AO and BO, the possible offspring genotypes are AB, BO, AO and OO, translating to the possible phenotypes: A, B, AB or O.

Hope this helped!

Answer 2

The parent genotypes are AO and BO.

Make a punnett square to see the genotypes of the offspring. I tried to make an example one below, but I suggest you draw one out for yourself.

A O

B AB BO

O AO OO

The four genotypes would be AB, BO, AO, and OO. Because A and B are dominant over the O allele, the phenotypes would just simply AB, B, A, and O.

So, Correct choice - d) A, B, AB, or O.