All Biology MCQs

Question 1

A pleiotropic gene:

Accepted Answer

Controls multiple traits in an individual

Answer

Controls a trait only in combination with another gene

Answer

Is expressed only in primitive plants

Answer

Is a gene evolved during Pliocene

Question 2

Locus stands for:

Accepted Answer

Position of gene on homologous chromosomes

Answer

Regions of chromosomes

Answer

Position of an allele within a DNA molecule.

Answer

Close regions of the same chromosomes.

Question 3

Mendel's laws are explained by:

Accepted Answer

Chromosomes behaviour in meiosis

Answer

Chromosomes behaviour in mitosis

Answer

Cytokinesis in mitosis and meiosis

Answer

Mendel's laws have not ben explained

Question 4

How many pairs of homologous chromosomes are present in Pisum sativum?

Accepted Answer

7

Answer

5

Answer

6

Answer

8

Question 5

The set of all genes in any population is termed as?

Accepted Answer

Gene pool

Answer

Population tool

Answer

Species tool

Answer

All of these options are correct

Question 6

Polyploidy is more common in:

Accepted Answer

Plants

Answer

Animals

Answer

Bacteria

Answer

Virus

Question 7

Flower color is controlled by a single pair of alleles. The allele for red flowers is dominant to the allele for white flowers. A plant homozygous for red flowers is crossed with a plant homozygous for white flowers. All the resulting plants have red flowers (F1 generation). When the F1 generation crosses with each other, 18 plants are obtained. 12 plants have red flowers and 6 have white flowers (F2 generation). What ratio is expected in the F2 generation and what ratio has been obtained?

Accepted Answer

3:1 expected, 2:1 obtained

Answer

2:1 expected, 3:1 obtained

Answer

1:1 expected, 3:1 obtained

Answer

1:1 expected, 2:1 obtained

Question 8

In our society women are blamed for producing female children. Choose the correct answer for the sex ­determination in humans.

Accepted Answer

Due to the genetic makeup of the particular sperm that fertilizes the egg

Answer

Due to a condition like aspermia in the man

Answer

Due to the genetic makeup of the egg

Answer

Due to a defect in the woman

Question 9

When hybrids are crossed, the genotype ratio of the offspring is

Accepted Answer

1:2:1

Answer

1:1

Answer

3:1

Answer

4:1

Answer

3:2

Question 10

Which of the following is the most suitable term for the genotype AaBb?

Accepted Answer

Heterozygous

Answer

Homozygous recessive

Answer

Homozygous dominant

Answer

None of these

Question 11

In peas, the gene for yellow color (C) is dominant to the gene for green color (c). To determine the genotype of an unknown yellow pea, what kind of pea should you cross with it?

Accepted Answer

Homozygous recessive (cc)

Answer

Another unknown green pea

Answer

Any genotype

Answer

Homozygous dominant

Question 12

Blood group AB can be donated to:

Accepted Answer

AB

Answer

A

Answer

B

Answer

All of the above options are correct

Question 13

The following results of a cross between two individuals shown in the picture are: Which statement describes the children of the cross?

Accepted Answer

Two child is homozygous recessive, and the other exhibits a dominant phenotype but has a parent with a recessive phenotype.

Answer

One child is homozygous dominant, while the other exhibits a dominant phenotype but has a parent with a recessive phenotype.

Answer

One child is homozygous recessive, and the other exhibits a dominant phenotype but has a sibling with a recessive phenotype.

Answer

One child is homozygous recessive, and another exhibits a recessive phenotype, but has a parent with a dominant phenotype.

Question 14

The "d" and "D" alleles are used for lighter and darker skin colour in humans, respectively. By keeping in view the inheritance pattern of skin colour in human beings(controlled by 3 genes), choose which combination shows medium skin colour from the following picture:

Accepted Answer

Column C

Answer

Column A

Answer

Column D

Answer

Column E

Question 15

Phenotype is.

Accepted Answer

The observable physical characteristics or traits of an organism

Answer

The genetic makeup of an organism

Answer

The environmental factors affecting an organism

Answer

The interaction between genotype and environment

Question 16

Dominance is the physiological effect of an allele over its partner allele occupying the;

Accepted Answer

Same locus on respective homologue

Answer

Same locus on same chromosome

Answer

Different locus on same chromosome

Answer

Different locus on respective homologue

Question 17

In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the F2 generation of the cross RRYY × rryy?

Accepted Answer

Round seeds with yellow cotyledons, and wrinkled seeds with green cotyledons

Answer

Only round seeds with green cotyledons

Answer

Only wrinkled seeds with yellow cotyledons

Answer

Only wrinkled seeds with green cotyledons

Question 18

Haemophilia is more commonly seen in human males than in human females because:

Accepted Answer

This disease is due to a X-­linked recessive mutation.

Answer

A greater proportion of girls die in infancy.

Answer

This disease is due to a Y-­linked recessive mutation.

Answer

This disease is due to an X-­linked dominant mutation.

Question 19

A woman with normal vision, but whose father was color blind, marries a color blind man. Suppose that the fourth child of this couple was a boy. This boy:

Accepted Answer

May be colour blind or may be of normal vision

Answer

Must be colour blind

Answer

Must have normal colour vision

Answer

Will be partially colour blind since he is heterozygous for the colour blind mutant allele

Question 20

Male XX and female XY sometime occur due to:

Accepted Answer

Transfer of segments in X and Y chromosome

Answer

Deletion

Answer

Aneuploidy

Answer

Hormonal imbalance

All Free Biology MCQs with Answers