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 (Reasons for Mendel's Work Neglect) with List-II (Description):

List-I	List-II
A. Lack of communication	I. Work could not be widely publicised in those days
B. Concept of discrete factors	II. Unaccepted due to perceived continuous variation in nature
C. Use of mathematics	III. Totally new and unacceptable to many biologists
D. Lack of physical evidence for factors	IV. Could not provide physical proof for existence or composition of factors

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: Communication issues limited publicity. The concept of discrete, non-blending factors was rejected in favor of continuous variation. The use of mathematics was unacceptable to biologists. Mendel lacked physical proof for the existence of factors.

Match List-I (Allele Pairs in ABO Group) with List-II (Dominance Relationship):

List-I	List-II
A. I A and i	I. I A is completely dominant over i
B. I B and i	II. I B is completely dominant over i
C. I A and I B	III. Co-dominance (both express their sugars)
D. I gene alleles (I A, I B, i)	IV. Multiple alleles governing the character

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: $I^A$ is completely dominant over $i$. $I^B$ is completely dominant over $i$. $I^A$ and $I^B$ show co-dominance. The existence of $I^A, I^B,$ and $i$ in the population is an example of multiple alleles.

Match List-I (Chromosomal Abnormality Mechanism) with List-II (Result/Cause):

List-I	List-II
A. Failure of chromatid segregation	I. Aneuploidy (gain or loss of a chromosome)
B. Failure of cytokinesis after telophase	II. Polyploidy (increase in a whole set of chromosomes)
C. Trisomy	III. Additional copy of a chromosome (e.g., Down’s Syndrome)
D. Monosomy	IV. Lack of one of any one pair of chromosomes (e.g., Turner’s Syndrome)

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: Failure of chromatid segregation causes aneuploidy. Failure of cytokinesis after telophase causes polyploidy. Trisomy is an additional copy of a chromosome. Monosomy is the lack of one chromosome from a pair.

Match List-I (Haplodiploid System Feature) with List-II (Description/Mechanism in Honey Bees):

List-I	List-II
A. Female (Queen/Worker)	I. Diploid (32 chromosomes)
B. Male (Drone)	II. Haploid (16 chromosomes)
C. Male development	III. From unfertilised egg (Parthenogenesis)
D. Sperm production by males	IV. Mitosis

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: Females are diploid (32 chromosomes). Males are haploid (16 chromosomes). Males develop via parthenogenesis from unfertilised eggs. Males produce sperm via mitosis.

Match List-I (Mendelian/Chromosomal Terms) with List-II (Definition):

List-I	List-II
A. Genetics	I. Deals with inheritance and variation of characters
B. Variation	II. Degree by which progeny differ from parents
C. Genes	III. Units of inheritance; stable units passed down
D. Chromosomes	IV. Structures in nucleus visualized by staining

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: Genetics is the subject dealing with inheritance and variation. Variation is the degree of difference of progeny from parents. Genes (Mendel's factors) are the units of inheritance. Chromosomes are colored bodies discovered in the nucleus through staining.

Match List-I (Dihybrid Cross Ratios) with List-II (Phenotype):

List-I (F2 Ratio Component)	List-II (Phenotype)
A. 9 parts	I. Round, Yellow
B. 3 parts (first)	II. Wrinkled, Yellow
C. 3 parts (second)	III. Round, Green
D. 1 part	IV. Wrinkled, Green

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 9:3:3:1 ratio in the dihybrid cross represents 9 Round, Yellow; 3 Wrinkled, Yellow; 3 Round, Green; and 1 Wrinkled, Green.

Match List-I (Chromosome Number) with List-II (Associated Disorder/Phenotype):

List-I	List-II
A. Trisomy of chromosome 21	I. Down’s Syndrome (47 total chromosomes)
B. 47, XXY karyotype	II. Klinefelter’s Syndrome
C. 45, X0 karyotype	III. Turner’s Syndrome
D. Chromosomal Aberrations	IV. Commonly observed in cancer cells

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: Trisomy 21 causes Down’s Syndrome. 47, XXY is the karyotype for Klinefelter’s Syndrome. 45, X0 is the karyotype for Turner’s Syndrome. Chromosomal aberrations (deletions/insertions) are commonly observed in cancer cells.

Match List-I (Mendelian/Chromosomal Theory Terminology) with List-II (Key Scientist):

List-I	List-II
A. Punnett Square	I. Reginald C. Punnett
B. Chromosomal Theory of Inheritance	II. Walter Sutton and Theodore Boveri
C. Experimental verification of Linkage	III. Thomas Hunt Morgan
D. Gene Mapping	IV. Alfred Sturtevant

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 Punnett Square was developed by Reginald C. Punnett. The Chromosomal Theory of Inheritance was proposed by Sutton and Boveri. T.H. Morgan provided experimental verification of linkage. Alfred Sturtevant used recombination frequency to map genes.

Match List-I (Haplodiploid Honey Bee Sex) with List-II (Parental Origin):

List-I	List-II
A. Female (Worker/Queen)	I. Union of sperm and egg (Fertilised egg)
B. Male (Drone)	II. Unfertilised egg (Parthenogenesis)
C. Drone's father	III. Males do not have a father
D. Drone's son	IV. Males cannot have sons, but can have grandsons

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: Females develop from the union of sperm and egg. Males develop from unfertilised eggs via parthenogenesis. A characteristic feature of the haplodiploid system is that males do not have a father. Males cannot have sons but can have grandsons.

Match List-I (Process/Cause) with List-II (Resulting Condition):

List-I	List-II
A. Single gene mutation (in PAH enzyme gene)	I. Phenylketonuria
B. Mutation in genes on X chromosome	II. Colour Blindness
C. Lack of single clotting protein	III. Haemophilia (non-stop bleeding)
D. Failure of segregation of alleles in $F_1$ (hypothetical)	IV. Blending of characters

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: Mutation in the gene for phenylalanine hydroxylase causes Phenylketonuria. Mutation in genes on the X chromosome causes colour blindness. Lack of a clotting protein causes Haemophilia. If segregation failed, blending would occur, which Mendel proved does not happen.

Principles of Inheritance and Variation: Class-XII

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