B6- Inherited Disorders

Question 1

What is cystic fibrosis caused by?

Answer 1

A recessive allele

Cystic fibrosis is a genetic disorder of the cell membranes resulting in thick sticky mucus production.

Question 2

How many carriers of the cystic fibrosis allele are there approximately?

Answer 2

1 in 25

Carriers are unaffected but can pass the allele to their offspring.

Question 3

For a child to have cystic fibrosis, what must be true about the parents?

Answer 3

Both parents must be carriers or have the disorder

The genetic representation is FF (unaffected), Ff (carrier), and ff (has cystic fibrosis).

Question 4

What is polydactyly?

Answer 4

A genetic disorder where a baby is born with extra fingers or toes

It is typically not life-threatening.

Question 5

What type of allele causes polydactyly?

Answer 5

A dominant allele

The allele is represented as ‘D’.

Question 6

What is the likelihood of a child having polydactyly if one parent has one D allele?

Answer 6

50% chance

The genetic representation includes Dd (has polydactyly) and dd (unaffected).

Question 7

What is the process during in vitro fertilisation (IVF)?

Answer 7

Embryos are fertilised in a laboratory and implanted into the mother’s womb

This allows for genetic analysis before implantation.

Question 8

What can be detected through embryo screening?

Answer 8

Many genetic disorders, such as cystic fibrosis

A cell can be removed from the embryo for genetic analysis.

Question 9

What are ethical concerns surrounding embryo screening?

Answer 9

It implies people with genetic problems are undesirable

This could increase social prejudice against those with genetic disorders.

Question 10

What are some arguments for embryonic screening?

Answer 10

• It will help to stop people suffering
• Treating disorders costs the Government a lot of money
• Allows parents to choose desirable traits

Arguments can vary widely, and there are laws to prevent misuse of screening.

Question 11

What are some arguments against embryonic screening?

Answer 11

• It implies that people with genetic problems are undesirable
• Screening is expensive

This raises concerns about discrimination and resource allocation.

Question 12

What can result from screening embryos in the womb?

Answer 12

The decision to terminate the pregnancy

This raises ethical concerns about the value of life.

Question 13

Fill in the blank: For embryos produced by IVF, embryos with ‘bad’ alleles would be _______.

Answer 13

destroyed

This is part of the ethical debate surrounding embryo screening.