Types of Monohybrid Cross – Check Test

1. A test cross is used to find the

A genotype of an individual showing a dominant characteristic.

B phenotype of an individual with an unknown genotype.

C genotype of an individual showing a recessive characteristic.

D phenotype of an individual with a known genotype.

Questions 2 and 3 refer to the following information.

In mice, the allele for black coat (B) is dominant to that for white coat (b).

2. A mouse with a black coat can be

A either homozygous dominant or homozygous recessive.

B either homozygous dominant or heterozygous.

C either homozygous recessive or heterozygous.

D only homozygous dominant.

3. A test cross was carried out to determine the genotype of a mouse

with a black coat.

A possible result of this test cross might be

A offspring all white.

B offspring all black.

C offspring all bb.

D offspring all recessive.

Questions 4 and 5 refer to the following information.

In pea flowers, the allele for red petal colour (R) is dominant to

that for white petal colour (r).

4. A cross between two plants produced offspring with a phenotype

ratio of 3 red petals : 1 white petals.

What were the genotypes of the parents?

A RR x rr

B Rr x rr

C Rr x RR

D Rr x Rr

5. If the cross RR x Rr is carried out, what will be the phenotype ratio

of the offspring

A 3 red petals : 1 white petal

B All red petals

C 1 red petal : 1 white petal

D All white petals

Questions 6, 7 and 8 refer to the following information.

The family tree shows the inheritance of albinism in a family.

It is a recessive condition involving lack of pigment in the skin, eyes

and hair.

6. How many individuals suffer from albinism?

A 2

B 3

C 4

D 9

7. Individual 8 has

A two normal alleles.

B the same alleles as his father.

C one normal and one recessive allele.

D two recessive alleles.

8. The genotype of which individuals can be identified from their phenotype?

A 2, 6, 8

B 2, 3, 11

C 5, 7, 9

D 2, 11, 12