Question

P indicates the allele for hairy stems and p indicates the allele for smooth stems.

Which statement about the offspring is correct?
p p
P
p


A.
50% will be heterozygous, 25% will be homozygous dominant, and 25% will be homozygous recessive.

B.
50% will be heterozygous, 0% will be homozygous dominant, and 50% will be homozygous recessive.

C.
75% will be heterozygous, 25% will be homozygous dominant, and 0% will be homozygous recessive.

D.
0% will be heterozygous, 25% will be homozygous dominant, and 75% will be homozygous recessive.

Answer 1

The answer is B. IF you do the punnett square, you should get Pp Pp pp pp. Heterozygous means one uppercase letter and one lowercase letter. There are 2, or 50%, combinations with one uppercase and one lowercase letter. Homozygous means two of the same alleles, or 2 uppercase/2 lower case letters. Since the pairs that are homozygous are pp and pp, there are 0% homozygous dominant, due to pp being recessive. So, we can conclude that there is 50% homozygous recessive. Let me know if that makes sense, it's hard to explain!