NEET MCQs Practice on Principles of Inheritance and Variation Class-XII Biology, Free unlimited practice on Principles of Inheritance and Variation Class-XII Biology Mcqs

Match List-I (Linkage/Recombination Data in Drosophila Cross A and Cross B) with List-II (Value/Concept):

List-I	List-II
A. Recombination percentage between yellow and white genes	I. 1.3 per cent
B. Recombination percentage between white and miniature wing genes	II. 37.2 per cent
C. Tightly linked genes	III. Show very low recombination
D. Linkage	IV. Physical association of genes on a chromosome

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Yellow and white genes showed 1.3% recombination (tight linkage). White and miniature wing genes showed 37.2% recombination (looser linkage).

Match List-I (Basic Ratios) with List-II (Monohybrid/Dihybrid/Test Cross):

List-I	List-II
A. F2 Phenotypic Ratio (Monohybrid Cross)	I. 3:1
B. F2 Genotypic Ratio (Monohybrid Cross)	II. 1:2:1
C. F2 Phenotypic Ratio (Dihybrid Cross)	III. 9:3:3:1
D. Test Cross (Tt x tt)	IV. 1:1

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: The F2 phenotypic ratio for a monohybrid cross is 3:1. The F2 genotypic ratio for a monohybrid cross is 1:2:1. The F2 phenotypic ratio for a dihybrid cross is 9:3:3:1. A test cross (Tt x tt) produces a 1:1 phenotypic ratio (e.g., violet:white).

Match List-I (Non-Mendelian Phenomena) with List-II (Trait/Mechanism):

List-I	List-II
A. Polygenic Inheritance	I. Traits generally controlled by three or more genes
B. Pleiotropy	II. Single gene exhibits multiple phenotypic expressions
C. Human Skin Colour	III. Phenotype influenced by multiple genes and environment
D. Phenylketonuria	IV. Classic example of pleiotropic disease in humans

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Polygenic traits are controlled by three or more genes. Pleiotropy is where a single gene produces multiple effects. Human skin colour is a classic example of polygenic inheritance influenced by environment. Phenylketonuria is a disease caused by a pleiotropic gene mutation.

Match List-I (ABO Blood Group Genotype) with List-II (Phenotype):

List-I	List-II
A. I^A I^A	I. Blood Group A
B. I^A I^B	II. Blood Group AB
C. I^B i	III. Blood Group B
D. i i	IV. Blood Group O

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: The phenotypes correspond directly to the genotypes provided in the table detailing the genetic basis of blood groups.

Match List-I (Sex Chromosome Karyotype) with List-II (Associated Human Syndrome/Condition):

List-I	List-II
A. 47, XXY	I. Klinefelter’s Syndrome
B. 45, X0	II. Turner’s Syndrome
C. Trisomy of Chromosome 21	III. Down’s Syndrome
D. Aneuploidy	IV. Gain or loss of chromosomes due to failure of segregation

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Klinefelter’s Syndrome has the karyotype 47, XXY. Turner’s Syndrome is 45, X0. Down’s Syndrome is caused by Trisomy 21. Aneuploidy is the gain or loss of a chromosome(s).

Match List-I (Sex-Linked Trait Feature) with List-II (Disorder):

List-I	List-II
A. Non-stop bleeding from a simple cut	I. Haemophilia
B. Failure to discriminate between red and green colour	II. Colour Blindness
C. X-linked recessive trait	III. Transmission from carrier female to male progeny
D. Queen Victoria	IV. Famous carrier of Haemophilia disease

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Haemophilia is a sex-linked recessive disease causing non-stop bleeding. Colour blindness is due to failure to discriminate red/green colour. X-linked recessive traits show transmission from carrier female to male progeny. Queen Victoria was a known carrier of Haemophilia.

Match List-I (Mendel’s Factors/Laws) with List-II (Core Concept):

List-I	List-II
A. Factors (Genes)	I. Contain information required to express a particular trait
B. Law of Independent Assortment	II. Segregation of one pair of characters is independent of the other pair
C. Alleles of a pair	III. Separate or segregate during gamete formation (Meiosis)
D. Dominant Allele	IV. The unmodified allele that produces a functional enzyme

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Factors (genes) contain the information for a trait. The Law of Independent Assortment deals with the independent segregation of two pairs of characters. Alleles of a pair segregate during gamete formation. The dominant allele is often the unmodified allele producing a functional enzyme.

Match List-I (Trait/Phenotype) with List-II (Gene/Allele Relationship):

List-I	List-II
A. Starch grain size in pea (Bb)	I. Incomplete dominance
B. Seed shape in pea (Bb)	II. Complete dominance
C. Flower color in Snapdragon (Rr)	III. Intermediate phenotype (Pink)
D. ABO blood grouping	IV. Co-dominance and Multiple alleles

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-I, C-IV, D-III
A-III, B-IV, C-I, D-II
A-IV, B-III, C-II, D-I

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Starch grain size in Bb is intermediate, showing incomplete dominance. Seed shape in Bb is round, showing complete dominance of R. Snapdragon Rr results in pink, an intermediate phenotype. ABO blood grouping involves three alleles (I^A, I^B, i) and shows co-dominance (I^A I^B).

Match List-I (Inheritance Studies) with List-II (Time Period/Context):

List-I	List-II
A. Mendel’s Hybridisation Experiments	I. 1856-1863 (Seven years)
B. Publication of Mendel’s work	II. 1865
C. Rediscovery of Mendel’s work (de Vries, Correns, von Tschermak)	III. 1900
D. Discovery of the X body (Henking)	IV. 1891

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-III, B-IV, C-I, D-II
A-I, B-III, C-II, D-IV
A-IV, B-II, C-I, D-III

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Mendel conducted experiments for seven years (1856-1863). He published his work in 1865. The work was independently rediscovered by three scientists in 1900. Henking traced the X body in 1891.

Match List-I (Genetic Terminology) with List-II (Mathematical Context):

List-I	List-II
A. Punnett Square	I. Graphical representation of offspring probability
B. Monohybrid F2 Genotype ratio (1:2:1)	II. Condensable to binomial expression (ax + by)<sup>2</sup>
C. Gamete formation (Tt plant)	III. 50 per cent chance of containing either allele
D. Dihybrid Cross F2	IV. Production of 16 possible zygote combinations

Choose the correct answer from the options given below:

[Principles-of-Inheritance-and-Variation] [class-xii ]

A-I, B-II, C-III, D-IV
A-II, B-III, C-I, D-IV
A-III, B-IV, C-I, D-II
A-IV, B-I, C-II, D-III

Correct Option: A [ A-I, B-II, C-III, D-IV ]

Remark: Punnett Square is a graphical representation to calculate probability. The 1:2:1 ratio is mathematically condensable to the binomial expression (ax + by)<sup>2</sup>. Gamete formation from Tt has a 50% chance for T or t. Dihybrid crosses involve 16 combinations in F2 using the Punnett Square.

Principles of Inheritance and Variation: Class-XII

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