Genetics worksheet with answers

In pea plants, purple flowers (A) are dominant over white (a). A plant with genotype AA is crossed with a plant with genotype Aa. What is the probability P that an offspring has purple flowers?

Two Bb parents are crossed. B gives round seeds and is dominant over b, which gives wrinkled seeds. Click the cell of the Punnett square for an offspring with wrinkled seeds.

1. 1B × B
2. 2B × b
3. 3b × B
4. 4b × b

red-green colour blindness is X-linked recessive (allele b). A carrier mother, X^BX^b, has children with an affected father, X^bY. The mother's gametes run down the side. Click the cell for an affected daughter.

1. 1X^b × X^b
2. 2X^b × Y
3. 3X^B × X^b
4. 4X^B × Y

red-green colour blindness is X-linked recessive (allele b). A carrier mother, X^BX^b, has children with an unaffected father, X^BY. The mother's gametes run down the side. Click the cell for an affected son.

1. 1X^B × Y
2. 2X^B × X^B
3. 3X^b × Y
4. 4X^b × X^B

In a population of 1000 in Hardy–Weinberg equilibrium, 16% show a recessive trait. How many individuals N are expected to be homozygous dominant?

Two AaBb parents are crossed. Gene A gives tall plants (dominant) or short plants; gene B gives purple flowers (dominant) or white flowers. Click the one cell for an offspring that is shows short plants and is homozygous for purple flowers.

1. 1aB × AB
2. 2aB × ab
3. 3aB × aB
4. 4aB × Ab
5. 5AB × AB
6. 6AB × ab
7. 7AB × aB
8. 8AB × Ab
9. 9ab × AB
10. 10ab × ab
11. 11ab × aB
12. 12ab × Ab
13. 13Ab × AB
14. 14Ab × ab
15. 15Ab × aB
16. 16Ab × Ab