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 Tt parents are crossed. T gives yellow seeds and is dominant over t, which gives green seeds. Click the cell for an offspring that has yellow seeds and is homozygous.

1. 1T × t
2. 2T × T
3. 3t × t
4. 4t × T

Tall (A) is dominant over short (a), and round seeds (B) over wrinkled (b). The genes are on different chromosomes. For the cross AaBb × aabb, what is the probability P that an offspring is tall, round seeds?

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an affected father, X^hY. The mother's gametes run down the side. Click the cell for a carrier daughter.

1. 1X^h × Y
2. 2X^h × X^h
3. 3X^H × Y
4. 4X^H × X^h

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

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

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