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Simple Genetics and Basic Punnett Squares

Total questions: 15

Worksheet time: 8mins

Name
Class
Date
1.

Which genotype is heterozygous for a single gene with alleles T (dominant) and t (recessive)?

a)

Tt

b)

tt

c)

TT

d)

tT

2.

Purple flowers are dominant to white. What phenotype results from genotype Pp?

a)

No flowers

b)

White flowers

c)

Purple flowers

d)

Mixed color

3.

Round seeds (R) are dominant to wrinkled seeds (r). Match each genotype to its phenotype.

a)

RR

1.

Round seeds

b)

Rr

2.

Round seeds

c)

rr

3.

Wrinkled seeds

4.

Pointed heads (P) are dominant to round heads (p). Which genotype set lists all individuals that would show pointed heads?

a)

Pp and pp

b)

PP and Pp

c)

PP only

d)

pp only

5.

Brown eyes (B) are dominant to blue (b). Which genotype is homozygous recessive?

a)

Bb

b)

bb

c)

bB

d)

BB

6.

A heterozygous round-seeded plant (Rr) is crossed with a homozygous round-seeded plant (RR). What percentage of offspring will be homozygous (RR)?

a)

25% of offspring

b)

50% of offspring

c)

75% of offspring

d)

100% of offspring

7.

In pea plants, purple flowers (P) are dominant to white flowers (p). If two white-flowered plants are crossed, what percentage of their offspring will have white flowers?

a)

50 percent of the offspring

b)

25 percent of the offspring

c)

0 percent of the offspring

d)

100 percent of the offspring

8.

A white-flowered pea plant (pp) is crossed with a plant that is heterozygous for purple flowers (Pp). What percentage of the offspring will have purple flowers?

a)

0 percent will be purple

b)

25 percent will be purple

c)

50 percent will be purple

d)

100 percent will be purple

9.

Two pea plants, both heterozygous for flower color (Pp × Pp), are crossed. What percentage of their offspring will have purple flowers?

a)

75 percent purple flowers

b)

50 percent purple flowers

c)

100 percent purple flowers

d)

25 percent purple flowers

10.

Two pea plants, both heterozygous for flower color (Pp × Pp), are crossed. What percentage of their offspring will have white flowers?

a)

25 percent white flowers

b)

50 percent white flowers

c)

75 percent white flowers

d)

100 percent white flowers

11.

In guinea pigs, short hair (S) is dominant to long hair (s). What genotype would a pure-breeding short-haired guinea pig have?

a)

Ss genotype for hair

b)

SS genotype for hair

c)

ss genotype for hair

d)

sS genotype for hair

12.

In guinea pigs, short hair (S) is dominant to long hair (s). What genotype would a long-haired guinea pig have?

a)

sS genotype for hair

b)

ss genotype for hair

c)

Ss genotype for hair

d)

SS genotype for hair

13.

Show the expected outcome for a cross between a pure-breeding short-haired guinea pig (SS) and a long-haired guinea pig (ss). What percentage of the offspring will have short hair?

a)

100 percent short-haired offspring

b)

0 percent short-haired offspring

c)

50 percent short-haired offspring

d)

25 percent short-haired offspring

14.

Two heterozygous guinea pigs (Ss × Ss) are crossed. What percentage of the offspring will have short hair?

a)

25 percent short-haired offspring

b)

50 percent short-haired offspring

c)

75 percent short-haired offspring

d)

100 percent short-haired offspring

15.

Two heterozygous guinea pigs (Ss × Ss) are crossed. What percentage of the offspring will have long hair?

a)

50 percent long-haired offspring

b)

100 percent long-haired offspring

c)

25 percent long-haired offspring

d)

75 percent long-haired offspring