Why does the woman not suffer from the condition? using a punnet square

Breaking down:

So, when it is said that the allele for PKU is recessive for the allele of no PKU, which means that if you have one allele of PKU and one allele of no PKU, the allele of no PKU will be applied.

When it is said that the woman is recessive, it means that she has only one allele of PKU, meaning that there is another one if no PKU, which is dominant and will prevent her from being diagnosed with phenylketonuria.

When it is said that the male os homozygous for the "normal allele" I do not know what it's supposed to mean, because there is no such thing as a "normal" or "anormal" gene. But still, it isn't important for answering the question.

Explanation:

The woman is heterozygous for PKU, which means that one of the two alleles is for PKU and the other one is for no PKU. Since the one for PKU is recessive, she will not suffer from the condition.

Note: I do not know why we're supposed to draw a punnet square, because we don't have information about her parents (this is something we could guess or make up (maybe predict) though) and that is not what is being asked in the image. If you still want to draw a punnet square, all you have to do is make sure that when the females parents breed, she inhertis the dominant allele (make sure she's heterozygous for PKU like she's supposed to be).

Hope it helped,

BioTeacher101