Genetic disorders Quiz
Studying this course? Keep your progress in one place.
Pick an answer for each. Quizzes never use energy.
5 questions, one answer each
Each answer is checked as you go, with why.
See all 5 questions
1. Polydactyly is caused by which type of allele?
- A. A dominant allele
- B. A recessive allele
- C. An abnormal number of chromosomes
- D. An allele on the Y chromosome only
2. Two parents, neither of whom has cystic fibrosis, have a child with cystic fibrosis. What does this tell us about the parents' genotypes?
- A. Both parents must be homozygous dominant
- B. Both parents must be carriers (heterozygous)
- C. One parent must have cystic fibrosis without symptoms
- D. The allele must have mutated in the child only
3. In a cross between two carriers of the sickle cell allele (Ss x Ss), what proportion of offspring are expected to have sickle cell anaemia?
- A. 1 in 4 (25%)
- B. 2 in 4 (50%)
- C. 3 in 4 (75%)
- D. 4 in 4 (100%)
4. What causes Down's Syndrome?
- A. A dominant allele on a single gene
- B. A recessive allele on a single gene
- C. The presence of an extra chromosome
- D. A mutation in a plasmid
5. A person is heterozygous for the polydactyly allele. Which statement is correct?
- A. They do not have polydactyly because they only have one copy of the allele
- B. They have polydactyly because the allele is dominant
- C. They are a carrier only and cannot pass the allele on
- D. They will only have polydactyly if they also inherit an extra chromosome