Inherited Disorders

Question 1

What is cystic fibrosis?

Answer 1

a genetic disorder effecting cell membranes resulting in overproduction of sticky mucus in the airways and pancreas

Question 2

what happens in the body of someone with cystic fibrosis?

Answer 2

the excessive mucus can block air passages and affect pancreatic function

Question 3

is the allele for cystic fibrosis dominant or recessive?

Answer 3

recessive

Question 4

what is the term for people who carry one copy of the cystic fibrosis allele but do not have the disorder themselves?

Answer 4

carriers

Question 5

how common is the cystic fibrosis allele in the population?

Answer 5

approximately 1 person in 25 have it

Question 6

what is polydactyly?

Answer 6

-a genetic disorder where a baby is born with extra fingers or toes
-it is not typically life threatening and does not cause any other problems

Question 7

what type of allele causes polydactyly?

Answer 7

the dominant allele ‘D’

Question 8

can polydactyly be inherited if just one parent carrier the defective allele?

Answer 8

yes as the allele is dominant

Question 9

what is the chance of a child having polydactyly is one parent has the ‘D’ allele ?

Answer 9

50%

Question 10

what is possible to do with embryos before IVF?

Answer 10

before implantation it is possible to remove a cell from each embryo and analyse its genes

Question 11

give an example of a genetic disorder that can be detected through embryo screening?

Answer 11

cystic fibrosis

Question 12

why might DNA testing be done on embryos in the womb?

Answer 12

to screen for genetic disorders

Question 13

what is the potential outcomes for embryos with ‘‘bad’’ alleles after screening during IVF?

Answer 13

they may be destroyed after screening

Question 14

what decision from a mother could embryo screening lead to?

Answer 14

pregnancy termintion

Question 15

what are the advantages of screening?

Answer 15

1)It will help to stop people suffering.
2) Treating disorders costs the Government (and the taxpayers) a lot of money.
3) There are laws to stop it going too far. e.g. parents cannot even select the sex of their baby (unless it’s for health reasons).

Question 16

what are the disadvantage of screening?

Answer 16

1)It implies that people with genetic problems are ‘undesirable’ — this could increase prejudice.
2) There may come a point where everyone wants to screen their embryos so they can pick the most ‘desirable’ one, e.g. they want a blue-eyed, blond-haired, intelligent boy.
3) Screening is expensive.