Principles of Inheritance & Variation: NEET MCQ Questions [100+ Solved]

Here you will find NEET MCQ questions on the Class 12 Biology Chapter “Principles of Inheritance and Variation” based on the NCERT textbook. Solve the below free NEET mock test for a better understanding of the various topics. 100+ important MCQs (multiple choice questions) are given in this NEET question bank.

“Principles of Inheritance and Variation” is the fifth chapter in the unit “Genetics and Evolution” of class XII or class 12th Biology NCERT. Do note that NEET (which is conducted by NTA) is based on NCERT books so they are a must have. You can also download PDF of NCERT textbooks.

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Genotype is
(a) Genetic composition of many organisms
(b) Genetic composition of plastids
(c) Genetic composition of germ cells
(d) Genetic composition of an individual

(d) Genetic composition of an individual

Mendelism is the genetics of
(a) Haploids
(b) Diploids
(c) Prokaryotes
(d) All the above

(b) Diploids

Which technique is used by Mendel for hybridization?
(a) Emasculation
(b) Bagging
(c) Protoplast fusion
(d) Both A & B

(d) Both A & B

Phenotypic ratio 3:1 proves
(a) Dominance
(b) Segregation
(c) Crossing over
(d) Independent Assortment

(b) Segregation

What is the ratio of homozygous plants for both dominant characters in F2 of a dihybrid cross?
(a) 1/16
(b) 3/16
(c) 4/16
(d) 9/16

(a) 1/16

Which of the following is the significance of dominance?
(a) Organisms with dominant genes are more vital
(b) Harmful mutations are not expressed due to dominant gene
(c) Heterosis is due to the dominant gene
(d) All the above

(b) Harmful mutations are not expressed due to dominant gene

From a single ear of corn, a farmer planted 200 kernels which produced 140 tall & 40 short plants. The genotypes of these offsprings are most likely
(a) TT, tt
(b) TT, Tt, tt
(c) TT, Tt
(d) Tt, tt

(b) TT, Tt, tt

A useful process for determining whether an individual is homozygous or heterozygous is
(a) cross-breeding
(b) self-fertilization
(c) Back-crossing
(d) Test cross

(d) Test cross

Heterozygous tall plants were crossed with dwarf plants what will be the ratio of dwarf plants in the following progeny?
(a) 50%
(b) 25 %
(c) 75%
(d) 100%

(a) 50%

Genetic recombinations occur through
(a) Mitosis & fertilization
(b) Mitosis & Meiosis
(c) Meiosis & fertilization
(d) None

Which of the following is the unit of inheritance?
(a) Phenotype
(b) Genotype
(c) Gene
(d) Genome

Allele is the
(a) Alternate trait of gene pair
(b) Total number of genes for a trait
(c) Total number of chromosomes
(d) Total number of chromosomes of a haploid set.

(a) Alternate trait of gene pair

Types of phenotypes of the F2 generation of dihybrid cross?
(a) 4
(b) 16
(c) 8
(d) 9

(a) 4

Cross XXYy and xxYy yields XxYY: XxYy : Xxyy: xxyy offspring in the ratio of
(a) 0 : 3 : 1 : 1
(b) 1 : 2 : 1 : 0
(c) 1 : 1 : 1 : 1
(d) 1 : 2 : 1 : 1

(b) 1 : 2 : 1 : 0

Genes do not occur in pairs in
(a) Zygote
(b) Somatic cell
(c) Endosperm cell
(d) Gametes

(d) Gametes

Genotype-Phenotype concept was first produced by
(a) Bateson
(b) Johannsen
(c) Sutton & Boveri
(d) Punnet

(b) Johannsen

1: 1: 1: 1 ratio shows
(a) Monohybrid cross
(b) Dihybrid cross
(c) Back cross
(d) Dihybrid test cross

(d) Dihybrid test cross

Test cross is
(a) Tt Tt
(b) Tt TT
(c) TT TT
(d) Tt tt

(d) Tt tt

In a plant, gene “T” is responsible for tallness and its recessive allele “t” for dwarfness and “R” is responsible for red colour flower and its recessive allele “r” of white flower colour. A tall and red-flowered plant with genotype TtRr crossed with dwarf and red-flowered ttRr. What is the percentage of dwarf white-flowered offspring of the above cross?
(a) 50%
(b) 6.25%
(c) 12.5 %
(d) 50 %

In the Mirabilis plant the appearance of the pink hybrid (Rr) between a cross of a red (RR) and white (rr) flower parent indicates
(a) Segregation
(b) Dominance
(c) Incomplete dominance
(d) Heterosis

If there were only parental combinations in F2 of a dihybrid cross then Mendel might have discovered?
(a) Independent assortment
(b) Atavism
(c) Linkage
(d) Repulsion

If the distance between the gene on the chromosome is more, then the gene shows
(a) less linkage
(b) strong linkage
(c) weak linkage
(d) incomplete linkage

(b) strong linkage

Which of the following conditions represent a case of co-dominant genes?
(a) A gene expresses itself, suppressing the phenotypic effect of its alleles
(b) genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait
(c) Alleles, both of which interact to produce an effect in homozygous condition
(d) Alleles, both of which interact to produce an independent effect in heterozygous conditions

(d) Alleles, both of which interact to produce an independent effect in heterozygous conditions

A gene located on y – chromosome and therefore, transmitted from father to son is known as
(a) Supplementary gene
(b) Complementary gene
(c) Duplicate gene
(d) Holandric gene

(d) Holandric gene

In a multiple allele system, a gamete possesses
(a) 2 alleles
(b) 3 alleles
(c) one allele
(d) several alleles

Blood grouping in humans is controlled by
(a) 4 alleles in which IA is dominant
(b) 3 alleles in which IA and IB are dominant
(c) 2 alleles in which none is dominant
(d) 3 alleles in which IA is recessive

(b) 3 alleles in which IA and IB are dominant

Multiple alleles are present
(a) in different chromosomes
(b) at different loci on chromosomes
(c) at the same locus on the homologous chromosome
(d) at the non-homologous chromosome

what is called pleiotropism?
(a) Phenomenon of multiple effects of a simple gene
(b) Phenomenon of multiple effects of multiple genes
(c) Phenomenon of multiple effects of multiple alleles
(d) all of the above

(a) Phenomenon of multiple effects of a simple gene

In a family, the father has a blood group ‘A’ and the mother has a blood group ‘B’, Children show 50% probability for a blood group “AB” indicate that
(a) Father is heterozygous
(b) Mother is heterozygous
(c) Either of the parent is heterozygous
(d) Mother is homozygous

The longer the chromosome of an organism, the more genetic variability it gets from,
(a) Independent assortment
(b) Linkage
(c) Crossing over
(d) Mutation.

Which statement is incorrect about linkage?
(a) It helps in maintaining the valuable traits of new varieties
(b) It helps in forming new recombinants
(c) Knowledge of linkage helps the breeder to combine all desirable traits in a single variety
(d) It helps in locating genes on the chromosome

(b) It helps in forming new recombinants.

Genetic balance theory for sex determination in Drosophila was proposed by
(a) Prof. R. P. Roy
(b) H. E. Warmed
(c) C.B. Bridges
(d) Mc. Chang

In Bonellia all larva are genetically and cytologically similar. In this worm, male individuals live in the uterus of females. If a particular larva settles near the proboscis of an adult female, it becomes a male individual. The larva develops free in water it becomes
(a) Male individuals
(b) Female individuals
(c) Inter Sex
(d) Super female

(b) Female individuals

The F2 generation is produced as a result of
(a) Crossing F1 individuals with the dominant parent
(b) Crossing F1 individuals with a recessive parent
(c) Crossing one of the parental individuals with the dominant individual
(d) Crossing F1 individuals amongst themselves.

(d) Crossing F1 individuals amongst themselves.

Segregation of genes takes place during which phase of cell division?
(a) Metaphase
(b) Anaphase
(c) prophase
(d) Embryo formation

(b) Anaphase

A couple has four daughters. The percentage probability of the fifth child to be a daughter is
(a) 10
(b) 50
(c) 75
(d) 100

(b) 50

In human being sex chromosomal complement is
(a) XX – XY
(b) XX – XO
(c) ZO – ZZ
(d) ZW – ZZ

(a) XX – XY

38 Zea mays have 10 pairs of chromosomes. Linkage groups present in it are
(a) 5
(b) 10
(c) 20
(d) 40

(b) 10

Crossing over during meiosis occurs between
(a) sister chromatids
(b) Non-sister chromatids
(c) Centromeres
(d) Non-homologous chromosomes

(b) Non-sister chromatids

Incomplete linkage in Drosophila produces offsprings with parental and non-parental combinations. State the percentage of the non-parental combination of Drosophila
(a) 83%
(b) 17 %
(c) 15 %
(d) 85 %

(b) 17 %

What does the term recombination describe?
(a) Generation of non-parental gene combination
(b) Generation of parental gene combination
(c) Generation of internal gene combination
(d) All of the above

(a) Generation of non-parental gene combination

A cross between hybrid and a parent is known as
(a) Test cross
(b) Back cross
(c) Monohybrid cross
(d) Reciprocal cross

(b) Back cross

Checkerboard method of calculations was developed by
(a) Mendel
(b) Bateson
(c) punnett
(d) Morgan

Punnet square is used to know
(a) the outcome of a cross
(b) the probable result of a cross
(c) Types of gametes
(d) Number of gametes

(b) the probable result of a cross

The first generation after a cross is
(a) First filial generation
(b) F1 gneratioon
(c) Second filial generation
(d) Both (a) and (b)

(d) Both (a) and (b)

In humans, height shows a lot of variation. It is an example of
(a) Multiple alleles
(b) Pleiotropic inheritance
(c) polygenic inheritance
(d) False allelic inheritance

Meiosis produces 4 daughter cells but each daughter cell differ from one another because of
(a) Crossing over
(b) Independent assortment
(c) Change in chromosome number
(d) Both A & B

(d) Both A & B

In T. H. Morgan’s Experiment on Drosophilia, what will be the result when F1 female flies are crossed with double recessive male flies?
(a) 83% parental combinations 17% Recombinations
(b) 41.5 % parental combinations 58.5% recombinations
(c) 60% parental combinations 40 % recombinations
(d) 90 % parental combinations 10% Recombinations

(a) 83% parental combinations 17% Recombinations

which cross yielded a ratio of 7:1 :1:7?
(a) Test cross (Dihybrid) – Bateson and punnet
(b) Test cross (Monohybrid) – Bateson and punnet
(c) Test cross (Dihybrid) – Carrel correns
(d) Test cross ( Dihybrid) – Mendel & Morgan

(a) Test cross (Dihybrid) – Bateson and punnet

When is there no possibility of an independent assortment of genes during gametogenesis then What Will be the real ratio of F2 in dihybrid cross?
(a) 9 : 3 : 3 : 1
(b) 11 : 1 : 1 : 3
(c) 12 : 1 : 1 : 2
(d) 9 : 3 : 2 : 2

(b) 11 : 1 : 1 : 3

What was the expected ratio of F2 by Bateson and Punnet in their dihybridization experiment done on Lathyrus odoratus?
(a) 9 : 3 : 3 : 1
(b) 11 : 1 : 1 : 3
(c) 12 : 1 : 1 : 3
(d) 9 : 3 : 2 : 2

(a) 9 : 3 : 3 : 1

What is an incorrect statement about Gynandromorphs?
(a) Individuals who show male characters and female characters
(b) Individuals who show only female characters
(c) It happens due to less of X- chromosomes
(d) It happens due to binucleated eggs

(b) Individuals who show only female characters

What is Barr’s body?
(a) One more than the number of X – chromosomes
(b) One more than the number of Y-chromosomes
(c) One less than the number of X – chromosomes
(d) Two less than the number of X – chromosomes

What is called Free martin?
(a) Sterile male born along with a fertile female
(b) Sterile intersex born along with a fertile female
(c) Sterile super male born along with an intersex
(d) Sterile female born along with a fertile male

(d) Sterile female born along with a fertile male

Out of the following, Find out the reason for the occurrence of free martin in cattle?
(a) Both the twins are connected by a common umbilical cord
(b) Gonad of the male develop earlier than those of the female
(c) Male hormones reach the female embryo and influence the development of male sex in the female embryo
(d) All of the above

(d) All of the above

In this group of plants, the male is heterogametic and the female is homogametic type
(a) Gymnosperms
(b) Bryophytes
(c) pteridophytes
(d) angiosperms

(d) angiosperms

Name the Plant possessing two X chromosomes
(a) Humulus japanic
(b) Dioscoria sinulate
(c) Flagellaria
(d) Both (a) & (b)

(d) Both (a) & (b)

State the mutant gene Which converts the male flowers into female flowers In Maize plant
(a) TA TA
(b) ta ta
(c) TA Ta
(d) Both (a) & (c)

(b) ta ta

By which gene sex is determined in Spinach?
(a) Single-gene “m” located in the X- chromosome
(b) Single-gene “m” located in the Y- chromosome
(c) Single-gene “t” located in the X- chromosome
(d) Single-gene “t” located in the Y- chromosome

(a) Single-gene “m” located in the X- chromosome

Which factor in nature causes discontinuous Variation in a population?
(a) Recombination
(b) Shuffling of parental genes
(c) Mutation
(d) Geneflow

This is a reversal of mutation
(a) Spontaneous mutation
(b) Zygotic mutation
(c) Back mutation
(d) Recessive mutation

Which condition among the following is lethal?
(a) (2n-2)
(b) (2n +2)
(c) (2n +1)
(d) (2n- 1)

(a) (2n-2)

State the cause of Philadelphia syndrome
(a) Deletion from the long arm of chromosome number 20
(b) Duplication in the long arm of chromosome number 20
(c) Deletion from the long arm of chromosome number 22
(d) Deletion from the short arm of chromosome number 22

which statement is incorrect regarding gene mutation
(a) Mutations may be gradual or they may not be induced.
(b) Mutation is an evolutionary agent
(c) Any gene can undergo mutation
(d) Mutated gene is harmful to the individual

(a) Mutations may be gradual or they may not be induced.

What happens to excessive phenylalanine accumulation in the blood of a phenylketonuria patient?
(a) Get deposited on synovial membrane
(b) excreted in urine
(c) Get deposited in storage organs
(d) All of the above

(b) excreted in urine

Name the enzyme needed for the following biochemical reaction: Tyrosine to Melanin
(a) Melanase
(b) tyrosinase
(c) Tyrosine aminase
(d) transaminase

(b) tyrosinase

Which is a very common method to study Human Karyotypes?
(a) Blood culture method
(b) Tissue culture method
(c) Pedigree method
(d) Statistical method

(a) Blood culture method

Large, thick, Swollen tongue and drooping lips are the symptoms of which genetical disorder
(a) Autosomal aneuploidy
(b) Trisomy of 21st chromosome
(c) Down’s syndrome
(d) Total number of chromosomes become 47

Name the disorder caused by the trisomy of sex chromosomes
(a) Down’s syndrome
(b) Klinefelter’s syndrome
(c) Turner’s syndrome
(d) Edward’s syndrome

(b) Klinefelter’s syndrome

Match the following
Column I Column II
1 Genetics a. Father of genetics
2 W.Bateson b. To become
3 “Gen” c. Coined the term genetics
4 Gregor Johann Mendel d. Study of heredity
(a) (1 – d) (2 – c) (3 – a) (4 – b)
(b) (1 – d) (2 – a) (3 – c) (4 – b)
(c) (1 – d) (2 – C) (3 – b) (4 – a)
(d) (1 – d) (2 – b) (3 – C) (4 – a)

Match the following
Column I Column II
1 Johansen a. Coined the term gene
2 Mendel b. Crossing over in drosophila
3 T. H. Morgan c. Linkage in lathyrus odoratus
4 Bateson & punnett d. Law of segregation
(a) (1 – d) (2 – c) (3 – b) (4 – a)
(b) (1 – a) (2 – d) (3 – b) (4 – c)
(c) (1 – c) (2 – d) (3 – b) (4 – a)
(d) (1 – b) (2 – d) (3 – a) (4 – c)

(b) (1 – a) (2 – d) (3 – b) (4 – c)

Match the following
Column I Column II
1 Single gene inheritance a. 1 : 1: 1 : 1
2 Double gene inheritance b. 1 : 2 : 1
3 Test cross c. 3 : 1
4 Incomplete dominance d. 9 : 3 : 3 : 1
(a) (1 – c) (2 – d) (3 – a) (4 – b)
(b) (1 – d) (2 – c) (3 – b) (4 – a)
(c) (1 – a) (2 – b) (3 – d) (4 – c)
(d) (1- d) (2 – b) (3 – a) (4 – c)

(a) (1 – c) (2 – d) (3 – a) (4 – b)

Match the following
Column I Column II
1 Codominance a. More than two optional forms of a gene
2 Polygenic inheritance b. Multiple effects of a single gene
3 Multiple alleles c. Quantitative inheritance
4 Pleiotropism d. Both gene express their expression independently
(a) (1 – d) (2 – c) (3 – a) (4 – b)
(b) (1 – a) (2 – c) (3 – b) (4 – d)
(c) (1 – d) (2 – a) (3 – c) (4 – b)
(d) (1 – a) (2 – b) (3 – d) (4 – c)

(a) (1 – d) (2 – c) (3 – a) (4 – b)

Match the following
Column I Column II
Blood groups Possible Genotypes
1 A (a) IB IB, IB i
2 B (b) ii
3 AB (c) IA IA, IA i
4 O (d) IA IB
(a) (1 – a) (2 – b) (3 – c) (4 – d)
(b) (1 – c) (2 – a) (3 – b) (4 – d)
(c) (1 – c) (2 – b) (3 – d) (4 – a)
(d) (1 – c) (2 – a) (3 – d) (4 – b)

(d) (1 – c) (2 – a) (3 – d) (4 – b)

The cross between heterozygous A blood group mother with B blood group father heterozygous). What will be the expected blood group of the first filial generation?
(a) AB group
(b) A group
(c) B group
(d) O group
(e) All of the above

(e) All of the above

What will be expected blood groups in the offspring when there is a cross between AB blood group mother and heterozygous B blood group father?
(a) 25 % AB group 25 % A group 50 % B group
(b) 50 % AB group 25 % A group 25 % B group
(c) 25% AB group 50% O group 25 % A group
(d) 25 % O group 50 % B group 25 % A group

(a) 25 % AB group 25 % A group 50 % B group

Which law of Mendel can be explained on the chromosomal basis of inheritance?
(a) Law of dominance
(b) Law of segregation
(c) Law of independent assortment
(d) All the above

The genes Controlling the seven characters of a pea plant studied by Mendel are now known to be located on how many different chromosomes?
(a) Seven
(b) Six
(c) Five
(d) Four

(d) Four

Which one of the following traits of garden pea studied by Mendel was a recessive feature?
(a) Axial flower position
(b) Green Seed colour
(c) Green pod colour
(d) Round Seed shape

(b) Green Seed colour

Down’s Syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father?
(a) 100%
(b) 75%
(c) 50%
(d) 25%

Lack of independent assortment of two genes A and B in fruitfly the Drosophilia is due to
(a) Repulsion
(b) Recombination
(c) Linkage
(d) Crossing over

A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic gene h. What proportion of his sperms will be abh?
(a) 1/8
(b) 1/32
(c) 1/16
(d) ¼

(a) 1/8

In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt.
(a) 25% will be tall with red fruit
(b) 50% will be tall with red fruit
(c) 75% will be tall with red fruit
(d) All the offspring will be tall with red fruit.

(b) 50% will be tall with red fruit

A normal woman, whose father was colour blind is married to a normal man. The sons would be
(a) 75% Colour blind
(b) 50% colour blind
(c) all normal
(d) all colourblind

(b) 50% colour blind

The recessive genes located on X – chromosomes of humans are always
(a) Lethal
(b) Sub – Lethal
(c) expressed in males
(d) expressed in females

To find out the different types of gametes produced by a pea plant having the genotype AaBb it should be crossed to a plant with the genotype
(a) AABB
(b) AaBb
(c) aabb
(d) aaBB

A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy
(a) Maybe colourblind or may be of normal vision
(b) Must be colourblind
(c) Must have normal colour vision
(d) Will be partially colourblind since he is heterozygous for the colourblind mutant allele.

(a) Maybe colourblind or may be of normal vision

Which of the following is not a hereditary disease?
(a) Cystic Fibrosis
(b) Thalassaemia
(c) Haemophilia
(d) Cretinism

(d) Cretinism

Haemophilia is more commonly seen in human males than in human females because
(a) a greater proportion of girls died in infancy
(b) this disease is due to a Y- Y-linked recessive mutation
(c) this disease is due to an X-linked recessive mutation
(d) this disease is due to an X-linked dominant mutation

A woman with 47 chromosomes due to 3 copies of chromosome 21 is characterized by
(a) Super Femaleness
(b) Triploidy
(c) Turner’s Syndrome
(d) Down’s Syndrome

(d) Down’s Syndrome

A man and a woman, who do not show any apparent signs of a certain inherited disease, have Seven Children (2 daughters and 5 sons). Three of the Sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?
(a) Sex-linked dominant
(b) Sex-linked recessive
(c) Sex – limited recessive
(d) Autosomal dominant

(b) Sex-linked recessive

Which one of the following is an example of polygenic inheritance?
(a) Skin colour in humans
(b) Flower colour in Mirabilis jalapa
(c) Production of male honey bee
(d) Pod shape in garden pea

(a) Skin colour in humans

Phenotype of an organism is the result of
(a) genotype and environmental interactions
(b) mutations and linkages
(c) Cytoplasmic effects and nutrition
(d) environmental changes and sexual dimorphism

(a) genotype and environmental interactions

How many different gametes will be produced by a plant having the genotype
AABbCC?
(a) Two
(b) Three
(c) Four
(d) Nine

(a) Two

In Mendel’s experiments with the garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), Yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected Phenotypes in the F2 generation of the cross RRYY x rryy?
(a) Round Seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
(b) Only round seeds with green cotyledons
(c) Only wrinkled seeds with yellow cotyledons
(d) Only wrinkled seeds with green cotyledons

(a) Round Seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons

Test cross involves
(a) Crossing between two genotypes with a dominant trait
(b) Crossing between two genotypes with a recessive trait
(c) Crossing between two F1 hybrids
(d) Crossing the F1 hybrid with a double recessive genotype

(d) Crossing the F1 hybrid with a double recessive genotype

Cri – du -chat Syndrome in humans is caused by the
(a) trisomy of the 21st chromosome
(b) Fertilization of an XX egg by a normal Y – bearing sperm
(c) loss of half of the short arm of chromosome 5
(d) loss of half of the long arm of chromosome 5

If a colourblind woman marries a normal visioned man, their sons will be
(a) all colourblind
(b) all normal visioned
(c) one – half colourblind and one-half normal
(d) three – fourths colourblind and one-fourth normal

(a) all colourblind

In the hexaploid wheat, the haploid (n) and basic (X) numbers of chromosomes are
(a) n = 21 and X = 21
(b) n = 21 and X =14
(c) n = 21 and X = 7
(d) n = 7 and X =21

Inheritance of skin colour in humans is an example of
(a) Point Mutation
(b) Polygenic inheritance
(c) Codominance
(d) Chromosomal aberrations

(b) Polygenic inheritance

In pea plants, yellow seeds are dominant to green, If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants, would you expect in the F1 generation?
(a) 9 : 1
(b) 1 : 3
(c) 3 : 1
(d) 50 : 50

(d) 50 : 50

A human male produces sperms with the genotypes AB, Ab, aB, ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?
(a) AaBB
(b) AABb
(c) AABB
(d) AaBb

(d) AaBb

Which one of the following conditions in a human is correctly matched with its chromosomal abnormality/linkage?
(a) Erythroblastosis foetalis – X-linked
(b) Down’s syndrome – 44 autosomes+XXY
(c) Kline Felter’s syndrome – 44 autosomes+XXY
(d) Colour blindness – Y-linked

The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because “O” in it refers to having
(a) Overdominance of this type on the genes for A and B types
(b) One antibody only – either anti – A or anti – B on the RBCs
(c) no antigens A and B on RBCs
(d) other antigens besides A and B on RBCs

Sickle cell anemia is
(a) Caused by substitution of Valine by glutamic acid in the beta-globin chain of haemoglobin.
(b) Caused by a change in a single base pair of DNA
(c) Characterized by elongated sickle-like RBCs with a nucleus
(d) An autosomal dominant trait

(b) Caused by a change in a single base pair of DNA

Which one of the following can not be explained based on 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 the F2 generation
(d) Factors occur in pairs

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

(a) test cross

Select the correct statement from the ones given below for the dihybrid cross.
(a) Tightly linked genes on the same chromosomes show higher recombinations
(b) Genes far apart on the same chromosome show very few recombinations
(c) Genes loosely linked on the same chromosome show similar recombinations
(d) Tightly linked genes on the same chromosome show very few recombinations

(d) Tightly linked genes on the same chromosome show very few recombinations

ABO blood groups in humans are controlled by gene I. It has three alleles – IA, IB, and i. Since there are 3 different alleles six different genotypes are possible. How many phenotypes occur?
(a) Three
(b) One
(c) Four
(d) Two

Mutations can be induced with
(a) Infrared radiations
(b) IAA
(c) Ethylene
(d) gamma radiations

(d) gamma radiations

Test cross in plants or Drosophilia involves crossing
(a) between two genotypes with a recessive trait
(b) between two F1 hybrids
(c) the F1 hybrid with a double recessive genotype
(d) between two genotypes with dominant traits

Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?
(a) Two X Chromosomes
(b) Only one Y Chromosome
(c) Only one X Chromosome
(d) One X chromosome and one Y chromosome

(a) Two X chromosomes

F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are the same as 1: 2: 1. It represents in case of
(a) Co-Dominance
(b) Dihybrid Cross
(c) Monohybrid cross with complete dominance
(d) Monohybrid cross with incomplete dominance

(d) Monohybrid cross with incomplete dominance

A normal visioned man whose father was colourblind, marries a woman whose father was also colourblind. They have their first child as a daughter. What are the chances that this child would be colourblind?
(a) 100%
(b) 0%
(c) 25%
(d) 50%

(b) 0%

A test cross is carried out to
(a) determine the genotype of a plant at F1
(b) Predict whether two traits are linked
(c) assess the number of alleles of a gene
(d) determine whether two species or varieties will breed successfully

(a) determine the genotype of a plant at F1

A cross between AaBB X aaBB yields a genotypic ratio of
(a) 1 AaBB : 1 aaBB
(b) I AaBB : 3aaBB
(c) 3 AaBB : 1 aaBB
(d) All AaBb

(a) 1 AaBB : 1 aaBB

Which of the following is non – heritable?
(a) Point mutation
(b) Chromosomal mutation
(c) Gene mutation
(d) Somatic mutation

(a) Point mutation

Dihybrid cross proves the law of
(a) segregation
(b) Purity of gametes
(c) Dominance
(d) Independent assortment

(a) segregation

How many types and in what ratio the gametes are produced by a dihybrid heterozygous?
(a) 4 types in the ratio of 9:3:3:1
(b) 2 types in the ratio of 3:1
(c) 3 types in the ratio of 1:2:1
(d) 4 types in the ratio of 1:1:1:1

(d) 4 types in the ratio of 1:1:1:1

In a cross between a pure tall plant with a green pod and a pure short plant with a yellow pod. How many short plants are produced in F2 generation out of 16?
(a) 1
(b) 3
(c) 4
(d) 9

In a dihybrid cross between AABB and aabb the ratio of AABB, AABb, aaBb, aabb in F2 generation is
(a) 9 : 3 : 3: 1
(b) 1: 1: 1: 1
(c) 1: 2: 2: 1
(d) 1 : 1 : 2 : 2

The allele which is unable to express its effect in the presence of another is called
(a) Co-dominant
(b) Supplementary
(c) Complementary
(d) Recessive

(d) Recessive