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 white flowers?

Two Tt parents are crossed. T gives purple flowers and is dominant over t, which gives white flowers. Click the cell for an offspring that has purple flowers and is homozygous.

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

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 unaffected son.

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

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 short, round seeds?

Two AaBb parents are crossed. Gene A gives yellow seeds (dominant) or green seeds; gene B gives black fur (dominant) or white fur. Click the one cell for an offspring that is shows both green seeds and white fur.

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 2000 in Hardy–Weinberg equilibrium, 1% show a recessive trait. How many individuals N are expected to be homozygous dominant?