Principles of Inheritance and Variation — Page 5 | NEET Biology

Q41

The genotypes of a husband and wife are IA IB and IA i. Among blood types of their children, how many different genotypes and phenotypes are possible?

A 3 genotypes; 4 phenotypes

B 4 genotypes; 3 phenotypes

C 4 genotypes; 4 phenotypes

D 3 genotypes; 3 phenotypes

Correct Answer

Option B

Solution

(b) 4 genotypes (IAIA, IAi, IAIB, IBi) and 3 phenotypes (A, B, AB).

Q42

Experimental verification of the chromosomal theory of inheritance was done by

A Sutton

B Boveri

C Morgan

D Mendel

Correct Answer

Option C

Solution

(c) T.H. Morgan experimentally verified the chromosomal theory of inheritance using Drosophila.

Q43

Which one of the following is an example of polygenic inheritance?

A Production of male honey bee

B Pod shape in garden pea

C Skin colour in humans

D Flower colour in Mirabilis jalapa

Correct Answer

Option C

Solution

(c) Human skin colour (controlled by 3 genes A, B, C) is the classic example of polygenic inheritance.

Q44

A human male produces sperms with genotypes AB, Ab, aB, and ab in equal proportions. The genotype of this person is

A AaBB

B AABb

C AABB

D AaBb

Correct Answer

Option D

Solution

(d) AaBb produces 4 gamete types in equal proportions: AB, Ab, aB, ab.

Q45

Inheritance of skin colour in humans is an example of

A point mutation

B polygenic inheritance

C codominance

D chromosomal aberration

Correct Answer

Option B

Solution

(b) Skin colour in humans is controlled by multiple genes (polygenic inheritance).

Q46

In pea plants, yellow seeds are dominant to green. A heterozygous yellow seeded plant is crossed with a green seeded plant. The expected ratio of yellow and green seeded plants in F1 is

A 9:1

B 1:3

C 3:1

D 50:50

Correct Answer

Option D

Solution

(d) Gg x gg gives 1 Gg (yellow) : 1 gg (green) = 50:50.

Q47

Two genes R and Y located very close on the chromosomal linkage map of maize are hybridized. F2 segregation will show

A segregation in expected 9:3:3:1 ratio

B segregation in 3:1 ratio

C higher number of parental types

D higher number of recombinant types

Correct Answer

Option C

Solution

(c) Closely linked genes give predominantly parental gametes, so more parental type offspring.

Q48

A common test to find the genotype of a hybrid is by

A crossing F2 progeny with female parent

B studying sexual behaviour of F1 progenies

C crossing F1 progeny with male parent

D crossing F2 progeny with male parent

Correct Answer

Option C

Solution

(c) Test cross: cross F1 with the homozygous recessive (male) parent.

Q49

Select the correct statement with respect to dihybrid cross

A Tightly linked genes on the same chromosome show higher recombinations

B Genes far apart on the same chromosome show very few recombinations

C Genes loosely linked show similar recombinations as tightly linked ones

D Tightly linked genes on the same chromosome show very few recombinations

Correct Answer

Option D

Solution

(d) Tightly linked genes (close together) show very low recombination frequency.

Q50

The genotype of a plant showing the dominant phenotype can be determined by

A test cross

B dihybrid cross

C pedigree analysis

D back cross

Correct Answer

Option A

Solution

(a) Test cross determines whether the dominant phenotype is homozygous or heterozygous.