Question

cystic fibrosis is an autosomal recessive genetic disorder.
cross a cystic fibrosis father with a carrier mother.
hint: it is a recessive disorder, so only people with a homozygous recessive genotype will have it (f x f)
place the fathers alleles on the top and the mothers alleles on the side
*phenotypes go in the right two boxes!

kids carrying c.f. =
kids having c.f. =

Explanation:

Step1: Define parental genotypes

Father (has C.F.): $ff$
Mother (carrier): $Ff$

Step2: Fill Punnett Square top row

Father's alleles: $f$, $f$

Step3: Fill Punnett Square side column

Mother's alleles: $F$, $f$

Step4: Combine alleles for offspring

Top-left: $F + f = Ff$
Top-right: $f + f = ff$
Bottom-left: $F + f = Ff$
Bottom-right: $f + f = ff$

Step5: Calculate carrier frequency

Carriers are $Ff$: $\frac{2}{4} = 50\%$

Step6: Calculate affected frequency

Affected are $ff$: $\frac{2}{4} = 50\%$

Answer:

Punnett Square filled:
Top (Father): $f$, $f$
Side (Mother): $F$, $f$
Offspring cells (top-left to bottom-right): $Ff$, $ff$, $Ff$, $ff$
Kids carrying C.F. = 50%
Kids having C.F. = 50%