MCQ Chapter 5 Principles of Inheritance and Variation Class 12 Biology

Please refer to Principles of Inheritance and Variation MCQ Questions Class 12 Biology below. These MCQ questions for Class 12 Biology with answers have been designed as per the latest NCERT, CBSE books, and syllabus issued for the current academic year. These objective questions for Principles of Inheritance and Variation will help you to prepare for the exams and get more marks.

Principles of Inheritance and Variation MCQ Questions Class 12 Biology

Please see solved MCQ Questions for Principles of Inheritance and Variation in Class 12 Biology. All questions and answers have been prepared by expert faculty of standard 12 based on the latest examination guidelines.

MCQ Questions Class 12 Biology Principles of Inheritance and Variation

Question- Genes which code for a pair of contrasting traits are known as
(a) Factors
(b) Alleles
(c) Hybrids
(d) None of These

Question- The allelic pair of genes which are identical are knows as
(a) Homozygous
(b) Heterozygous
(c) Dominant
(d) Recessive

Question- Gametes are produced by the process of
(a) Asexual reproduction
(b) Meiosis
(c) Mitosis
(d) Binary fission

Question- In monohybrid cross (TT × tt) the F1 and F₂ generation each have how many small squares in Punnett square?
(a) 4 in F₁ and 16 in F₂
(b) 4 in F₁ and 8 in F₂
(c) 4 each in F₁ and F₂
(d) 2 in F₁ and 4 in F₂

Question- Self pollination of F₂ generation dwarf plants produced by a monohybrid cross (TT × tt)
(a) Produced only dwarf plants (homozygous) in F₃ and F₄ generation
(b) Produced only dwarf plants (heterozygous) in F₃ and F₄ generation
(c) This concluded that genotype of dwarf in F₂ was heterozygous
(d) (a) and (c) are true

Question- Test cross of F₂ generation tall plants produced 50% tall and 50% dwarf plants. The genotype F2 generation tall plant would be :
(a) Tt
(b) tt
(c) TT
(d) Dd

Question- Organism showing dominant phenotype (heterozygous) is crossed with the recessive parent it will produce
(a) 25% dominant and 75% recessive offspring
(b) 50% dominant and 50% recessive offspring
(c) 75% dominant and 75% recessive offspring
(d) All dominant offspring

Question- Statement incorrect for law of dominance.
(a) Characters are controlled by factors
(b) Factors occurs in pair and if are contrasting then one will dominate and other is recessive
(c) This law is used to explain the expression parental characters is monohybrid cross (TT × tt), which is in 3:1 ratio F₁ and F₂ generation.
(d) The genotype shown in F₂ is 1:2:1

Question- Law of incomplete dominance was done in
(a) Garden pea
(b) Chick pea
(c) Dog
(d) Dog plant

Question- When in a monohybrid Cross the F₁ does not match to any of the parent and shows character in between the two this is
(a) Law of dominance
(b) Codominance
(c) Law of segregation
(d) Law of incomplete dominance

Question- The monohybrid cross of red and white flowers in snapdragon plant produced flowers of how many colours in F₂ generation
(a) Three red, white and orange
(b) Two red and white
(c) Three red, white and pink
(d) All red

Question- In codominance the F₁ generation resembles
(a) Dominant parent
(b) Recessive parent
(c) Shows in–between character of both parents
(d) None of these

Question- How many alleles are there for blood group determining genes?
(a) 2
(b) 4
(c) 3
(d) None of these

Question- If IA and lo are the alleles present in a person which blood group is expressed
(a) B
(b) A
(c) 0
(d) AB

Question- How many phenotypes of blood groups generated due to three alleles of gene for expressing sugar on RBC in a population
(a) 3
(b) 6
(c) 4
(d) None of these

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

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

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- If the DMA codons are ATG ATG ATG and a cytosine base is inserted at the beginning, which of the following will result?
(a) CATGATGATG
(b) CAT GAT GAT G
(c) CATGATGATG
(d) a nonsense mutation

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- In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F1 generation all pink flowers were obtained. When pink flowers were selfed, the F2 generation showed white, red and pink flowers. Choose the incorrect statements from the following.
(a) Law of segregation does not apply in this experiment.
(b) This experiment does not follow the Principle of Dominance.
(c) Pink colour in F1 is due to incomplete dominance.
(d) Ratio of F2 is 142414():():().redpinkwhite

Question- Some of the dominant traits studied by Mendel were
(a) round seed shape, constricted pod shape and axial flower position
(b) green pod colour, inflated pod shape and axial flower position
(c) yellow seed colour, violet flower colour and yellow pod colour
(d) axial flower position, green pod colour and green seed colour.

Question- Which one of the following cannot be explained on the basis of Mendel’s Law of Dominance?
(a) The discrete unit controlling a particular character is called a factor.
(b) Out of one pair of factors one is dominant, and the other recessive.
(c) Alleles do not show any blending and both the characters recover as such in F2 generation.
(d) Factors occur in pairs.

Question- In garden pea, round shape of seeds is dominant over wrinkled shape. A pea plant heterozygous for round shape of seed is selfed and 1600 seeds produced during the cross are subsequently germinated. How many seedlings would have the parental phenotype?
(a) 400
(b) 1600
(c) 1200
(d) 800

Question- Among the following characters, which one was not considered by Mendel in his experiments on pea?
(a) Trichomes-Glandular or non-glandular
(b) Seed-Green or yellow
(c) Pod-Inflated or constricted
(d) Stem-Tall or dwarf

Question- If a cross between two individuals produces offspring with 50% dominant character(A) and 50% recessive character (a) the genotype of parents are
(a) Aa, Aa
(b) Aa, aa
(c) AA, aa
(d) AA, Aa

Question- When red and white flowered Mirabilis plants are crossed all pink flowers are seen in F1 generation. When F1 progeny is selfed, the expected phenotypic and genotypic ratios are
(a) 1:2:1 and 3:1:1
(b) 3:1 and 1:2:1
(c) 1:2:1 and 1:2:1
(d) 1:1 and 1:1:1

Question- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of
(a) 3 : 1 : : Tall : Dwarf
(b) 3 : 1 : : Dwarf : Tall
(c) 1 : 2 : 1 : : Tall homozygous : Tall heterozygous : Dwarf
(d) 1 : 2 : 1 : : Tall heterozygous : Tall homozygous : Dwarf

Question- In an organism, tall phenotype is dominant over recessive dwarf phenotype, and the alleles are designated as T and t, respectively. Upon crossing two different individuals, total 250 offsprings were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parents were
(a) TT × TT
(b) TT × tt
(c) Tt × Tt
(d) Tt × tt

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 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- 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- Tritieale has been produced by intergeneric hybridization between
(a) wheat and rye
(b) wheat and rice
(c) wheat and Adgilops
(d) rice and maize

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

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

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

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

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

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

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

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

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

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

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

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

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- 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- The phenotypic and genotypic ratios remain same in F2 generation in case of
(a) dihybrid cross
(b) supplementary genes
(c) incomplete dominance
(d) inhibitory genes

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

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- Imagine that in 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

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

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

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

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