Inheritance - cystic fibrosis

Question 1

what disorder is cystic fibrosis of?

Answer 1

cell membranes. it is inherited

Question 2

what is cystic fibrosis controlled?

Answer 2

single gene which has 2 alleles

Question 3

what is the allele for a normal cell membrane function?

Answer 3

dominant ‘C’

Question 4

what is the allele for defective cell membranes?

Answer 4

recessive ‘c’

Question 5

what alleles does a person need in order to have cystic fibrosis?

Answer 5

two copies of the defective allele. inherit a defective allele from both parents.

Question 6

what is a carrier of the cystic fibrosis allele?

Answer 6

where a person has one defective allele and one normal allele. they don’t have cystic fibrosis. they are heterozygous

Question 7

how to figure out what child will have
father =carrier of cystic fibrosis (Cc)
mother= unaffected (CC)

Answer 7

create a punnet square
C c
C
C
50% = unaffected
50% = carrier

Question 8

what is possible from the probabilities predicted in a punnet square?

Answer 8

possible all offspring could be carriers or all unaffected

Question 9

work out phenotype and genotype?
Father = carrier (Cc)
Mother = carrier (Cc)
C c
C
c

Answer 9

CC Cc
cC cc
25% =unaffected (homozygous) 50%= carrier (heterozygous) 25%= cystic fibrosis (homozygous)