Unit Test: Heredity | Science Class 10 PDF Download

Time: 1 hour

M.M. 30

Attempt all questions.

• Question numbers 1 to 5 carry 1 mark each.
• Question numbers 6 to 8 carry 2 marks each.
• Question numbers  9 to 11 carry 3 marks each.
• Question number 12 & 13 carry 5 marks each

Q1: A zygote which has an X chromosome inherited from the father will develop into a:
(a) boy
(b) girl
(c) X chromosome does not determine the sex of a child
(d) either boy or girl

Q2: In peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in F₂ is
(a) 1:3
(b) 3:1
(c) 1:1
(d) 2:1

Q3: Assertion (A): Human female has a perfect pair of sex chromosomes.
Reason (R): Sex chromosome contributed by the human male in the zygote decides the sex of a child.
(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Q4: A trait in an organism is influenced by
(a) paternal DNA only
(b) maternal DNA only
(c) both maternal and paternal DNA
(d) neither by paternal nor by maternal DNA

Q5: Assertion (A): Human population shows a great deal of variations in traits.
Reason (R): All variations in a species have equal; chances of surviving in the environment in which they live.  (1 Mark) 
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A)
(b) Both Assertion (A) and Reason (R) are true, but; Reason (R) is not the correct explanation of the Assertion (A)
(c) Assertion (A) is true, but Reason (R) is False.
(d) Assertion (A) is false, but Reason (R) is true  

Q6: A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F1 progeny? (2 Marks)

Q7: What is the difference between Recessive and Dominant Traits? (2 Marks)

Q8: Why is the progeny always tall when a tall pea plant is crossed with a short pea plant? (2 Marks)

Q9: Explain how the sex of the child is determined at the time of conception in human beings. (3 Marks)

Q10:  The survival of a species is promoted through the creation of variations. Illustrate with an example. (3 Marks)

Q11: Why did Mendel choose a pea plant for his experimentation? (3 Marks)

Q12: Explain Mendel’s experiment with peas on inheritance of characters considering only one visible contrasting character. ( 5 Marks)

Q13: A green stemmed rose plant denoted by GG and a brown stemmed rose plant denoted by gg are allowed to undergo a cross with each other. (5 Marks)

(a) List your observations regarding:
(i) Colour of stem in their F₁ progeny
(ii) Percentage of brown stemmed plants in F₂ progeny if plants are self pollinated.
(iii) Ratio of GG and Gg in the F₂ progeny.

(b) Based on the findings of this cross, what conclusion can be drawn?

You can find the solutions of this Unit Test here: Unit Test (Solutions): Heredity​