Simple Inheritance in Animals and Plants: Genetic Disorders

Question 1

What allele causes cystic fibrosis?

Answer 1

recessive allele

Question 2

What is cystic fibrosis?

Answer 2

disorder of cell membranes causes production of thick, sticky mucus

Question 3

How many parents need to have the allele for it to be passed on?

Answer 3

both

Question 4

Symptoms of Cystic fibrosis

Answer 4

• breathing difficulty
• respiratory infections
• lower growth rate than expected
• difficulty in exercise

Question 5

Why is breathing affected by cystic fibrosis and how can it be treated?

Answer 5

• thick mucus prevents oxygen from diffusing across alveoli into blood
• Treatment: physiotherapy/ enzyme DNAase(using nebulizer)

Question 6

Why are respiratory infections caused by cystic fibrosis and how can it be treated?

Answer 6

• thick mucus traps bacteria in lungs which go onto reproduce and cause infection
• Treatment: antibiotics - kill specific bacteria/reduces MRSA

Question 7

Why is growth rate affected by cystic fibrosis and how can it be treated?

Answer 7

• pancreatic duct blocked with mucus so digestive enxymes cannot break down food, food not used so won’t be used for growth
• Treatment: digestive enzymes - food supplement breakdwon food

Question 8

Why is exercise affected by cystic fibrosis and how can it be treated?

Answer 8

• requires increased respiration to produce more energy for muscles to contract but mucus prevents flow of oxygen so difficulty to exercise
• Treatment: no treatment - choice of exercise is limited

Question 9

What allele causes polydactyly?

Answer 9

dominant allele

Question 10

What is polydactyly?

Answer 10

extra fingers or toes

Question 11

How many parents need to have the allele for it to be passed on?

Answer 11

only one

Question 12

How can we test for genetic disorders?

Answer 12

embryo screening

Question 13

arguments for embryo screening

Answer 13

• stop suffering of child
• advanced knowledge - prepare for lifestyle
• help decision to abort
• used to grow new tissues and organs

Question 14

arguments against embryo screening

Answer 14

• destroys potential life (human rights)
• opposes religious views
• creates stress for parents
• expensive process
• removing alleles from population in future may be needed for survival
• 50% chance child will be normal