Principles of Inheritance and Variation Questions — NEET Biology

Q1

Ratio of complementary genes in F2

A 9:3:4

B 12:3:1

C 9:3:3:4

D 9:7

Correct Answer

Option D

Solution

(d) Complementary gene interaction: 9:3:3:1 becomes 9:7 when both dominants needed for expression.

Q2

Mongoloid idiocy in humans is also known as

A Tay Sachs disease

B Klinefelter syndrome

C Down syndrome

D Turner syndrome

Correct Answer

Option C

Solution

(c) Down syndrome (trisomy 21) is characterized by Mongoloid features.

Q3

The genes controlling the seven pea characters studied by Mendel are located on how many different chromosomes?

A Four

B Seven

C Six

D Five

Correct Answer

Option A

Solution

(a) Mendel's seven traits are on 4 chromosomes (some are far apart on the same chromosome).

Q4

Which one of the following traits of garden pea studied by Mendel was a recessive feature?

A Round seed shape

B Axial flower position

C Green seed colour

D Green pod colour

Correct Answer

Option C

Solution

(c) Green seed colour is recessive; yellow is dominant.

Q5

ABO blood group system is due to

A multifactor inheritance

B incomplete dominance

C multiple allelism

D epistasis

Correct Answer

Option C

Solution

(c) ABO blood groups are controlled by three multiple alleles: IA, IB, and IO.

Q6

Test cross involves

A crossing between two F1 hybrids

B crossing F1 hybrid with double recessive genotype

C crossing between two genotypes with dominant trait

D crossing between two genotypes with recessive trait

Correct Answer

Option B

Solution

(b) Test cross = F1 dominant x homozygous recessive parent.

Q7

If two persons with AB blood group marry and have many children, children could be classified as A:AB:B in 1:2:1 ratio. This is an example of

A incomplete dominance

B partial dominance

C complete dominance

D codominance

Correct Answer

Option D

Solution

(d) ABO blood groups where IA and IB are codominant.

Q8

In a population of 1000 individuals 360 are AA, 480 are Aa, and 160 are aa. The frequency of allele A is

A 0.4

B 0.5

C 0.6

D 0.7

Correct Answer

Option C

Solution

(c) p = (2×360 + 480)/(2×1000) = 1200/2000 = 0.6.

Q9

Fruit colour in squash is an example of

A Recessive epistasis

B Dominant epistasis

C Complementary genes

D Inhibitory genes

Correct Answer

Option B

Solution

(b) Summer squash fruit colour shows dominant epistasis (W_ masks colour).

Q10

The term linkage was coined by

A T. Boveri

B G. Mendel

C W. Sutton

D T.H. Morgan

Correct Answer

Option D

Solution

(d) T.H. Morgan coined the term linkage.