BIO 3030 FINAL EXAM STUDY GUIDE: 100 GENETICS PRACTICE QUESTIONS & ANSWER KEY

BIO 3030 FINAL EXAM STUDY
GUIDE: 100 GENETICS PRACTICE
QUESTIONS & ANSWER KEY


1. Q: State Mendel’s law of segregation.

A: Alleles separate during gamete formation, so each

gamete carries only one allele per gene.
2. Q: What is a testcross?

A: A cross with a homozygous recessive individual to

determine an unknown genotype.

3. Q: What is the phenotypic ratio of a monohybrid cross Aa

× Aa?

A: 3:1.
4. Q: What is the phenotypic ratio of a dihybrid cross AaBb

× AaBb?

A: 9:3:3:1.
5. Q: In AaBb × AaBb, what is the probability of aabb
offspring?
A: 1/16.

, 6. Q: A person with blood type AB has children with a person
with blood type O. What blood types are possible?
A: A or B only.

7. Q: In incomplete dominance, what is the F2 ratio after
selfing pink F1 plants?
A: 1 red : 2 pink : 1 white.

8. Q: Give an example of codominance.

A: AB blood type.

9. Q: What is pleiotropy?
A: One gene affects multiple traits.

10. Q: Give an example of polygenic inheritance.

A: Human skin color or height.

11. Q: What phenotypic ratio is typical of recessive
epistasis?

A: 9:3:4.
12. Q: An affected father and a carrier mother for an X-
linked recessive trait. What is the chance of an affected

son?
A: 50%.
13. Q: Why are X-linked recessive traits more common in

males?