Please refer to Chapter 5 Principles of Inheritance and Variation MCQ Class 12 Biology with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Biology. Students should refer to MCQ Questions for Class 12 Biology with Answers to score more marks in Grade 12 Biology exams. Students should read the chapter Principles of Inheritance and Variation and then attempt the following objective questions.

MCQ Questions Class 12 Biology Chapter 5 Principles of Inheritance and Variation

The Principles of Inheritance and Variation MCQ Class 12 Biology provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. If parents have O and AB blood group their children can have the possibility of having which blood groups
(a) Only A
(b) Only B
(c) Only AB
(d) Can be either A or B blood group

Question. State which of the following is not true.
A. Dominance is a autonomous feature of a gene or the product.
B. A single gene product may produce only one effect.
C. Blood group AB is an example of codominance.
D. More than two alleles exist is a population for a single gene
Options :
(a) A
(b) A and C
(c) B and D
(d) A and B

Question. The phenotype ratio o F₂ or single character used in dihybrid will be
(a) 15:1
(b) 9:3:3:1
(c) 3:1
(d) 1:2:1

Question. In dihybrid cross (RRYY × rryy) the ratio of pure dominant species : pure recessive species in F₂ generation genotype will be
(a) 3 : 1
(b) 1 : 2
(c) 1 : 1
(d) None of these

Question. F₂ generation of dihybrid cross (RRYY × rryy) shows which genotype offspring in maximum number
(a) Pure recessive
(b) Pure dominant
(c) hybrid dominant
(d) recessive dominant

Question. Mendel’s work was published in the year
(a) 1863
(b) 1865
(c) 1890
(d) 1902

Question. Meiosis is
(a) Equivalent division
(b) Non Equivalent division
(c) Reduction division
(d) Both (a) and (c)

Question. Two alleles are gene pairs located at
(a) Homologous site on homologous chromosomes
(b) Heterologous site on homologous chromosome
(c) Both (a) and (b)
(d) None of these

Question. Scientist who was not involved in the rediscovery of Mendel’s results on the inheritance of characters
(a) Devries
(b) T. Boveri
(c) Correns
(d) Von Tshermark

Question. What is true about chromosomal theory of inheritance
(a) It was given by W. Sutton and T. Bovery
(b) It is based on Mendel’s law and chromosomal segregation during meiosis
(c) Cell division knowledge was helpful in postulating the law
(d) All of these

Question. Experimental organism used by T.H. Morgan was
(a) Garden pea
(b) Snap dragon
(c) Fruit fly
(d) Chick pea

Question. In his experiment Morgan used female flies with
(a) Brown bodies, red eyed
(b) Yellow bodies, white eyed
(c) Brown bodies, white eyed
(d) Yellow bodies, red eyed

Question. The phenotype ratio of F₂ generation of Morgan’s cross in D. Melanogaster was
(a) 1 : 2 : 1
(b) 1 : 2 : 1 : 2 : 2 : 4 : 1 : 2 : 1
(c) 9 : 3 : 3 : 1
(d) Significantly deviated from 9 : 3 : 3 : 1

Question. Initial experiments for sex determination were performed in
(a) Garden pea
(b) Dog plant
(c) Human
(d) Insects

Question. Mendel’s monohybrid ratio is-               
(a) 1:2
(b) 3:1
(c) 9:3:3: 1
(d) 9:7

Question. Who is considered as father of genetics?               
(a) Hugode Vries
(b) Morgan
(c) Mendel
(d) Darwin

Question. Pleiotropic gene has –                   
(a) single genotype
(b) multiple genotype
(c) multiple phenotype
(d) single phenotype

Question. Substitution of a purine nucleotide by pyrimidine nucleotide is called           
(a) transition
(b) transversion
(c) inversion
(d) transduction

Question. The exposure of X-rays enhances the frequency of                       
(a) linkage
(b) crossing over
(c) pairing of chromosomes
(d) segregation

Question. The combined form of coupling and repulsion is –           
(a) crossing over
(b) mutation
(c) linkage  
(d) disjunction

Question. How many contrasting characters were selected by Mendel?             
(a) One
(b) Two
(c) Three
(d) Seven

Question. A cross between F1 hybrid and a recessive parent (Tt x tt) gives a ratio of –
(a) 1:1
(b) 2:1
(c) 3: 1
(d) 4:1

Question. An allele is dominant, if it is expressed in –           
(a) second generation
(b) homozygous combination
(c) heterozygous combination
(d) both homozygous and heterozygous conditions

Question. Atall red-flowered pea plant after crossing with a dwarf white-flowered plant yields only tall red-flowered plants. Atest cross shall give a ratio of     
(a) 1 : 1
(b) 3 : 1
(c) 1 : 2 : 4 : 6 : 4 : 2 : 1
(d) 1 : 1 : 1 : 1

Question. An organism with two identical alleles is said to be –               
(a) hybrid
(b) homozygous
(c) heterozygous
(d) dominant

Question. A test cross enables one to                             
(a) determine the viability of cross
(b) distinguish between homozygous dominant and heterozygous dominant
(c) determine whether two species can interbreed
(d) determine the similarities in the DMA of two species

Question. In sweet pea, the epistatic interaction between the genes for purple and white colour produced the two colours in the ratio-             
(a) 3:1
(b) 8:8
(c) 9:3:3: 1
(d) 9:7

Question. Which one of the following is the genotypic ratio in monohybrid cross?               
(a) 9:3:3:1
(b) 1:2:1
(c) 9:7
(d) 3 : 1

Question. Which of the following truly represents a heterozygous organism?         
(a) XXyy
(b) RRYy
(c) xxYY
(d) RrYy

Question. ABO blood groups is determined by                       
(a) three recessive alleles
(b) three codominant alleles
(c) three alleles, two dominant and one recessive
(d) three alleles, two recessive and one dominant

Question. When a gene pair hides the effect of another, the phenomenon is called –
(a) mutation
(b) dominance
(c) epistasis
(d) none of these

Question. Mendel did not propose the theory of –                           
(a) dominance
(b) incomplete dominance
(c) segregation
(d) independent assortment

Question. A cross between hybrid and recessive parent is             
(a) back cross
(b) test cross
(c) monohybrid cross
(d) dihybrid cross

Question. Inheritance of skin colour in human beings is an example of –                   
(a) polygenic inheritance
(b) Mendelian inheritance
(c) monogenic inheritance
(d) complementary genes

Question. A cross between parents with AaBB and aaBB genotype will form –                   
(a) all AaBB
(b) 1 AaBB : 3 aaBB
(c) 1 AaBB : 1 aaBB
(d) 3 AaBB : 1 aaBB

Question. How many types of gametes will be produced by individuals of AABbcc genotype ?                           
(a) Two
(b) Four
(c) Six
(d) Nine

Question. Which of the following proved an exception to Mendel’s principles?                 
(a) dominance
(b) linkage
(c) independent assortment
(d) purity of gametes/segregation

Question. In a red and white-flowered cross of Mirabilisjalapa, F2 generation has red, pink and white-flowered plants in the ratio of                       
(a) 2 : 1 : 1
(b) 1 : 1 : 2
(c) 1 : 2 : 1 –
(d) 1:0:1

Question. The different forms of a gene are called –       
(a) heterozygotes
(b) alleles
(c) supplementary genes
(d) complementary genes

Question. In keeping with the law of independent assortment what is actually assorted?       
(a) Different genes on the same chromosome
(b) Centromeres
(c) Homologous chromosomes
(d) Heterologous chromosomes

Question. In the AB blood group the two genes are                 
(a) codominant
(b) corecessive
(c) incompletely dominant
(d) dominant-recessive

Question. A woman with one gene for haemophilia and a gene for colour blindness on one of X chromosomes marries a normal man. How will the progeny be?                 
(a) All sons and daughters haemophilic and colour blind
(b) 50% haemophilic colour blind sons and 50% normal sons
(c) 50% haemophilic daughters and 50% colour blind daughters
(d) Haemophilic and colour blind daughters

Question. Haemophilia is more common in males because it is a-         
(a) recessive trait carried b>,{chromosome
(b) dominant trait carried by X chromosome
(c) recessive character carried by Y chromosomes
(d) dominant character carried by Y chromosome

Question. Which one of the following is a sex-linked disease?           
(a) Nightblindness
(b) Glaucoma
(c) Haemophilia
(d) All of these

Question. The substance, which causes a definite change in genes is called Biology 75               
(a) toxin
(b) alkaloid
(c) cytotoxin
(d) mutagen

Question. Crossing over in diploid organisms is responsible for             
(a) linkage between genes
(b) segregation of alleles
(c) dominance of genes
(d) recombination of linked genes

Question. In Mendel’s experiments the alleles were         
(a) codominant
(b) corecessive
(c) dominant-recessive
(d) incompletely dominant

Question. Multiple alleles control the character of             
(a) only skin colour
(b) only blood groups
(c) blood groups and skin colour
(d) sickle-cell

Question. Human skin colour is controlled by .             
(a) a single allele
(b) two alleles
(c) atleast three separate genes
(d) four alleles

Question. A child with mother of A group and father of AB group, will not have the following blood group –       
(a) A
(b) B
(c) AB
(d) O

Question. Two dominant independently assorting genes react with each other. They are   
(a) supplementary
(b) complementary
(c) duplicate
(d) collaborative

Question. A blue fowl obtained from mating between black and white fowls, is self-crossed. The F2 ratio is           
(a) 1 black : 2 white : 1 blue
(b) 1 black : 2 blue : 1 white
(c) 2 black : 1 white : 1 blue
(d) none of these

Question. A single recessive trait which can express its effect should occur on               
(a) any chromosome
(b) anyautosome
(c) X chromosome of male
(d) X chromosome of female

Question. Chiasrna represents the site of         
(a) homologous chromosome
(b) crossing over
(c) pachytene
(d) diakinesis

Question. A family of five daughters only is expecting sixth issue. The chance of its being son is                   
(a) zero
(b) 25%
(c) 50%
(d) 100%

Question. Gene located on the same locus but having different expressions are                   
(a) oncogenes
(b) polygenes
(c) multiple alleles
(d) codominants

Question. Mendel’s dihybrid ratio is               
(a) 15:1
(b) 9:3:3:1
(c) 1 : 2 : 1
(d) 9 : 6 : 1

Question. The ratio 9 : 7 is produced due to –
(a) complementary genes
(b) supplementary genes             
(c) lethal genes
(d) epistatic genes

Question. Polygenesare                 
(a) genes which control continuously variable characters like height, weight, etc.
(b) multiple copies of a single gene
(c) always linked genes
(d) pseudogenes

Question. How many types of gametes will be produced by individuals having genotype AaBbCc?                             
(a) Two
(b) Four ‘
(c) Six
(d) Eight

Question. The meaning of syndrome is related to                       
(a) dwarf organ ism
(b) diseased condition
(c) a group of symptoms
(d) viral disease

maize plant, the factors for controlling seed coat and seed shape are present on the same chromosome very close together. Performing dihybrid experiments with these characters, Mendel would not have been able to arrive at the idea of –     
(a) Dominance
(b) Independent assortment
(c) Incomplete dominance
(d) Segregation

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