HEREDITY

1. Who is known as the “Father of Genetics”?

a) Charles Darwin

b) Gregor Mendel

c) Watson and Crick

d) Robert Hooke

2. What are the alternate forms of a gene called?

a) Chromatids

b) Alleles

c) Genotypes

d) Loci

3. Mendel conducted his experiments on which plant?

a) Wheat

b) Pea

c) Rice

d) Tomato

4. Which law states that allele pairs separate independently during gamete
formation?

a) Law of Segregation

b) Law of Independent Assortment

c) Law of Dominance

d) Law of Linkage

5. The physical expression of a gene is called:

a) Genotype

b) Phenotype

c) Allele

d) Trait

6. A cross between two heterozygous tall pea plants (Tt × Tt) results in which
ratio of tall to short plants?
A) 3:1

b) 1:2:1

c) 2:2

d) 1:1

7. Which of the following is an example of a recessive trait in humans?

a) Curly hair

b) Brown eyes

c) Blue eyes

d) Dark skin

8. Which of these represents a heterozygous condition?

a) TT

b) tt

c) Tt

d) None of these

9. The chromosome number in human sperm or egg is:

a) 23

b) 46

c) 22

d) 44

10. DNA is located inside:

a) Mitochondria

b) Ribosome

c) Nucleus

d) Cytoplasm

11. Which of the following determines the sex of a child?

a) Mother’s chromosome

b) Father’s chromosome

c) Both parents equally

d) Environmental factors
12. If a pure tall plant (TT) is crossed with a pure dwarf plant (tt), what will
be the phenotype of the F1 generation?

A) All tall

b) All dwarf

c) 50% tall, 50% dwarf

d) 75% tall, 25% dwarf

13. The chemical structure of genes is:

a) Protein

b) Carbohydrate

c) DNA

d) RNA

14. In a monohybrid cross, which law explains the separation of alleles

during gamete formation?

a) Law of Independent Assortment

b) Law of Segregation

c) Law of Dominance

d) Law of Co-dominance

15. What is the ratio of phenotypes in a dihybrid cross (AaBb × AaBb)?

a) 9:3:3:1

b) 3:1

c) 1:2:1

d) 1:1

16. The number of chromosomes in a normal human body cell is:

a) 22

b) 23

c) 44

d) 46

17. Which of the following is NOT a characteristic of dominant traits?

a) Expressed in heterozygous condition

b) Represented by uppercase letters

c) Always inherited by offspring

d) Masks recessive traits

18. A recessive allele is expressed when:

a) One dominant allele is present

b) Two recessive alleles are present

c) Both dominant and recessive alleles are present

d) None of the above

19. The sex of a human baby is determined by:

a) XX chromosome combination

b) XY chromosome combination

c) Autosomes

d) Mitochondrial DNA

20. Which scientist discovered the structure of DNA?

a) Gregor Mendel

b) Watson and Crick

c) Darwin

d) Hugo de Vries

21. Variations in a species arise due to:

a) Mutation

b) Reproduction

c) Environmental factors

d) All of the above

22. Inherited traits are passed from:

a) Parents to offspring

b) Siblings to siblings

c) Environment to organism

d) Teachers to students
23. The part of DNA that codes for a protein is called:

a) Chromosome

b) Gene

c) Ribosome

d) Cytoplasm

24. What type of reproduction leads to maximum genetic variations?

a) Asexual reproduction

b) Sexual reproduction

c) Binary fission

d) Budding

25. If an organism has two identical alleles for a trait, it is called:

a) Heterozygous

b) Homozygous

c) Hybrid

d) Variant

26. The carriers of hereditary information are:

a) Ribosomes

b) Chromosomes

c) Lysosomes

d) Endoplasmic Reticulum

27. Why did Mendel choose pea plants for his experiments?

a) They grow slowly

b) They have many observable traits

c) They require special care

d) They reproduce asexually

28. In a dihybrid cross, which two traits did Mendel study?

a) Flower color and height

b) Seed color and seed shape

c) Leaf shape and fruit size

d) Stem color and flower shape

29. The presence of different eye colors in humans is an example of:

a) Acquired traits

b) Inherited traits

c) Environmental adaptation

d) None of these

30. Which law of Mendel states that one allele can mask the expression of
another?

a) Law of Segregation

b) Law of Independent Assortment

c) Law of Dominance

d) Law of Evolution

ANSWERS

1. B) Gregor Mendel
2. B) Alleles
3. B) Pea
4. B) Law of Independent Assortment
5. B) Phenotype
6. A) 3:1
7. C) Blue eyes
8. C) Tt
9. A) 23
10. C) Nucleus

11. B) Father’s chromosome

12. A) All tall
13. C) DNA
14. B) Law of Segregation
15. A) 9:3:3:1
16. D) 46
17. C) Always inherited by offspring
18. B) Two recessive alleles are present
19. B) XY chromosome combination
20. B) Watson and Crick
 21. D) All of the above
22. A) Parents to offspring
23. B) Gene
24. B) Sexual reproduction
25. B) Homozygous
26. B) Chromosomes
27. B) They have many observable traits
28. B) Seed color and seed shape
29. B) Inherited traits
30. C) Law of Dominance

Assertion and Reason Questions

1. Assertion (A): Traits are transferred from parents to offspring through

genes.
Reason (R): Genes are located on chromosomes.

2. Assertion (A): In a monohybrid cross, the F₂ generation shows a 3:1

ratio of dominant to recessive traits.
Reason (R): The dominant trait gets expressed only in the
heterozygous condition.

3. Assertion (A): Variation is important for evolution.

Reason (R): Variations help individuals adapt better to their
environment.

4. Assertion (A): A son inherits the X chromosome from his father.

Reason (R): The sex of a child is determined by the chromosomes
inherited from the father.

5. Assertion (A): A recessive trait is always expressed in the F₁

generation.
Reason (R): A trait is recessive only when it is present in a
heterozygous condition.

6. Assertion (A): The law of independent assortment states that genes

for different traits are inherited together.
Reason (R): Mendel’s experiments proved that traits are inherited as
discrete units.

7. Assertion (A): A child inherits mitochondrial DNA only from the

mother.
Reason (R): Mitochondria are present only in the sperm and not in
the egg.

8. Assertion (A): The characters or traits that appear in the first filial
(F₁) generation are always dominant.
 Reason (R): Dominant traits suppress the expression of recessive
traits.

9. Assertion (A): In humans, males have one X and one Y chromosome.

Reason (R): The Y chromosome carries genes that determine
maleness.

10. Assertion (A): Fossils provide evidence of evolution.

Reason (R): Fossils help in tracing evolutionary relationships among
organisms.

11. Assertion (A): Sexual reproduction leads to greater variations in

offspring.
Reason (R): Genetic recombination during gamete formation causes
variations.

12. Assertion (A): Identical twins have exactly the same genetic
makeup.
Reason (R): Identical twins arise from two different zygotes.

13. Assertion (A): Acquired traits are inherited by the next

generation.
Reason (R): Only genetic changes in reproductive cells can be passed
on to offspring.

14. Assertion (A): In a dihybrid cross, the F₂ generation shows a

9:3:3:1 phenotypic ratio.
Reason (R): Genes for different traits assort independently during
gamete formation.

15. Assertion (A): The evolution of a species is influenced by

natural selection.
Reason (R): Natural selection favors individuals with beneficial
variations, leading to the survival of the fittest.

Answers

1. B (Both A and R are true, but R is not the correct explanation of A)

2. C (A is true, but R is false)

3. B (Both A and R are true, but R is not the correct explanation of A)

4. D (A is false, but R is true)

5. C (A is true, but R is false)

6. C (A is true, but R is false)

7. D (A is false, but R is true)

8. B (Both A and R are true, but R is not the correct explanation of A)

9. B (Both A and R are true, but R is not the correct explanation of A)

10. B (Both A and R are true, but R is not the correct explanation of
A)

11. B (Both A and R are true, but R is not the correct explanation of
A)

12. C (A is true, but R is false)

13. D (A is false, but R is true)

14. B (Both A and R are true, but R is not the correct explanation of
A)

15. B (Both A and R are true, but R is not the correct explanation of
A)

PRACTICE CROSSES

1. In a cross between a homozygous tall (TT) pea plant and a

homozygous dwarf (tt) plant, what will be the genotype of the F₁
generation?
a) TT
b) Tt
c) tt
d) TT and Tt

2. A heterozygous tall (Tt) plant is crossed with a homozygous dwarf

(tt) plant. What will be the phenotypic ratio?
a) 100% Tall
b) 50% Tall, 50% Dwarf
c) 75% Tall, 25% Dwarf
d) 100% Dwarf

3. A cross between two heterozygous tall (Tt) plants produces

offspring. What is the genotypic ratio in the F₂ generation?
a) 1:2:1 (TT:Tt:tt)
b) 3:1 (Tall:Dwarf)
c) 50% Tall, 50% Dwarf
d) 100% Tall

4. If a homozygous round (RR) pea plant is crossed with a

homozygous wrinkled (rr) plant, what will be the phenotype of the F₁
generation?
 a) 100% Round
b) 50% Round, 50% Wrinkled
c) 75% Round, 25% Wrinkled
d) 100% Wrinkled

5. In a monohybrid cross of Tt × Tt, what fraction of the offspring will be

heterozygous?
a) 100%
b) 75%
c) 50%
d) 25%

6. In a dihybrid cross between RRYY (Round Yellow) and rryy

(Wrinkled Green) peas, what will be the phenotype of the F₁
generation?
a) 100% Round Yellow
b) 75% Round Yellow, 25% Wrinkled Green
c) 50% Round Yellow, 50% Wrinkled Green
d) 100% Wrinkled Green

7. In a dihybrid cross between two heterozygous (RrYy × RrYy)

plants, what is the expected phenotypic ratio in the F₂ generation?
a) 3:1
b) 9:3:3:1
c) 1:2:1
d) 50% Round, 50% Wrinkled

8. What fraction of offspring from a dihybrid cross (RrYy × RrYy) will be

homozygous recessive for both traits (rryy)?
a) 1/16
b) 3/16
c) 9/16
d) 4/16

9. A homozygous round green (RRyy) pea plant is crossed with a

homozygous wrinkled yellow (rrYY) pea plant. What will be the
genotype of the F₁ generation?
a) RrYy
b) RRYY
c) rryy
d) RRyy

10. In a dihybrid cross between RrYy × rryy, what percentage of

offspring will have a round green phenotype?
a) 9/16
 b) 3/16
c) 4/16
d) 1/16

11. Which of the following laws states that alleles separate

independently during gamete formation?
a) Law of Segregation
b) Law of Independent Assortment
c) Law of Dominance
d) Law of Variation

12. In a monohybrid cross between Tt × Tt, which Mendelian law is

demonstrated?
a) Law of Segregation
b) Law of Independent Assortment
c) Law of Variation
d) Law of Mutation

13. In a dihybrid cross, which Mendelian ratio is observed in the F₂

generation?
a) 3:1
b) 9:3:3:1
c) 1:2:1
d) 50% Tall, 50% Dwarf

14. The dominant trait suppresses the expression of the

recessive trait in which of the following Mendelian laws?
a) Law of Segregation
b) Law of Independent Assortment
c) Law of Dominance
d) Law of Co-dominance

15. A heterozygous round yellow (RrYy) pea plant is crossed with a

homozygous wrinkled green (rryy) plant. Which of the following will be
the most common phenotype in the F₁ generation?
a) Round Yellow
b) Wrinkled Green
c) Round Green
d) Wrinkled Yellow

16. If a heterozygous tall (Tt) pea plant is crossed with a

homozygous tall (TT) plant, what percentage of the offspring will be
tall?
a) 50%
b) 75%
 c) 100%
d) 25%

17. In a dihybrid cross (RrYy × RrYy), what percentage of offspring

will have wrinkled green seeds (rryy)?
a) 6.25%
b) 9.5%
c) 25%
d) 30%

18. If a carrier female (XhX) for hemophilia is crossed with a

normal male (XY), what is the probability of a hemophilic son?
a) 0%
b) 25%
c) 50%
d) 100%

19. A heterozygous blood group A (IAi) person marries a

heterozygous blood group B (IBi) person. What percentage of their
children will have blood group O?
a) 0%
b) 25%
c) 50%
d) 75%

20. A colorblind male (XcY) is crossed with a normal female (XX).

What percentage of daughters will be carriers for color blindness?
a) 0%
b) 25%
c) 50%
d) 100%

ANSWERS

1. b) Tt

2. b) 50% Tall, 50% Dwarf

3. a) 1:2:1 (TT:Tt:tt)

4. a) 100% Round

5. c) 50%

6. a) 100% Round Yellow

7. b) 9:3:3:1

8. a) 1/16
9. a) RrYy

10. c) 4/16

11. b) Law of Independent Assortment

12. a) Law of Segregation

13. b) 9:3:3:1

14. c) Law of Dominance

15. a) Round Yellow

16. c) 100%

17. a) 6.25%

18. c) 50%

19. b) 25%

20. c) 50%