What is the chance that a child will have PKD if the father is unaffected and the mother is heterozygous

1/4 The father is also heterozygous.

Explanation:

PKD is an autosomal recessive disorder. It results when a child has both recessive alleles for the Gene. So for the child to have the disorder when the mother is heterozygous, then the father must also be heterozygous

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.