Principles of Inheritance and Variation — Page 3 | NEET Biology

Q21

How many different kinds of gametes will be produced by a plant having the genotype AABbCC?

A Four

B Nine

C Two

D Three

Correct Answer

Option C

Solution

(c) AABbCC produces only 2 gamete types: ABC and AbC.

Q22

In Antirrhinum (Snapdragon), red x white gave pink in F1. When pink flowers were selfed, F2 showed white, red and pink. Choose the incorrect statement

A This experiment does not follow the principle of dominance

B Pink colour in F1 is due to incomplete dominance

C Ratio of F2 is 1 Red:2 Pink:1 White

D Law of Segregation does not apply in this experiment

Correct Answer

Option D

Solution

(d) Law of Segregation is universally applicable; incomplete dominance only violates dominance.

Q23

Phenotype of an organism is the result of

A cytoplasmic effects and nutrition

B environmental changes and sexual dimorphism

C genotype and environment interactions

D mutations and linkages

Correct Answer

Option C

Solution

(c) Phenotype = genotype + environment interaction.

Q24

When dominant and recessive alleles express themselves together it is called

A codominance

B dominance

C amphidominance

D pseudodominance

Correct Answer

Option A

Solution

(a) Codominance: both alleles express themselves fully in the heterozygote.

Q25

A woman with an albinic father marries an albinic man. The proportion of her progeny is

A 2 normal:1 albino

B all normal

C all albino

D 1 normal:1 albino

Correct Answer

Option D

Solution

(d) Woman is Aa (carrier); albinic man is aa. Cross: Aa × aa = 1 normal (Aa) : 1 albino (aa).

Q26

The most striking example of point mutation is found in

A thalassemia

B night blindness

C Down syndrome

D sickle cell anaemia

Correct Answer

Option D

Solution

(d) Sickle cell anaemia: single nucleotide change (GAG→GTG) is the classic point mutation.

Q27

Genetic identity of a human male is determined by

A autosomes

B nucleolus

C sex chromosomes

D cell organelles

Correct Answer

Option C

Solution

(c) Sex chromosomes (XY in males) determine genetic sex identity.

Q28

Number of Barr bodies in each somatic cell of a normal female (XX) is

A 1

B 2

C 3

D 0

Correct Answer

Option A

Solution

(a) Normal female (XX) has 1 Barr body (one X is inactivated).

Q29

When a cluster of genes show linkage behaviour they

A induce cell division

B do not show a chromosome map

C show recombination during meiosis

D do not show independent assortment

Correct Answer

Option D

Solution

(d) Linked genes on the same chromosome do not assort independently.

Q30

In which mode of inheritance do you expect more maternal influence?

A Cytoplasmic

B Y-linked

C X-linked

D Autosomal

Correct Answer

Option A

Solution

(a) Cytoplasmic (maternal) inheritance: organelle genes are transmitted through maternal cytoplasm.