Vardaan Learning Institute

Topic: Heredity

Class: 10 (Science) Type: Bonus Practice Paper Max. Marks: 50
Name:
Date:
SECTION A: OBJECTIVE TYPE QUESTIONS (1 Mark Each)
1. The genetic constitution of an organism is known as:
  1. Phenotype
  2. Genotype
  3. Allele
  4. Factor
2. A plant with genotype Tt is crossed with a plant with genotype tt. The percentage of offspring which are short is:
  1. 25%
  2. 50%
  3. 75%
  4. 100%
3. In human males, the sex chromosomes are:
  1. XX
  2. XY
  3. YY
  4. No sex chromosomes
4. Which of the following is an example of a recessive trait in pea plants?
  1. Tall Stem
  2. Round Seed
  3. Green Pod
  4. Wrinkled Seed
5. Mendel selected pea plants because:
  1. They were cheap
  2. They were easily available
  3. They had many contrasting characters
  4. They were tall
6. Who is known as the Father of Genetics?
  1. Charles Darwin
  2. Gregor Johann Mendel
  3. Lamarck
  4. Robert Hooke
7. A zygote which has an X-chromosome inherited from the father will develop into a:
  1. Boy
  2. Girl
  3. X-chromosome does not determine the sex of a child
  4. either Boy or Girl
8. Which of the following is an inherited trait?
  1. Reduction in weight of an organism due to starvation
  2. Removal of tail in mice by surgery
  3. Colour of eyes
  4. Knowledge of French language
9. If a tall pea plant is crossed with a pure dwarf pea plant then what percentage of F1 and F2 generation respectively will be tall?
  1. 25%, 25%
  2. 50%, 50%
  3. 75%, 25%
  4. 100%, 75%
10. The maleness of a child is determined by:
  1. The X chromosome in the zygote
  2. The Y chromosome in zygote
  3. The cytoplasm of germ cell
  4. Sex is determined by chance
Directions (Q11-Q14): In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
11. Assertion (A): The sex of a child into human beings is determined by the father.
Reason (R): Human males have one X and one Y chromosome.
12. Assertion (A): Variations decrease the chances of survival of a species in a changing environment.
Reason (R): Variation is the raw material for evolution.
13. Assertion (A): A geneticist crossed a pea plant having violet flowers with a pea plant with white flowers, he got all violet flowers in first generation.
Reason (R): White flower trait is recessive trait and violet flower trait is dominant.
14. Assertion (A): Traits like tallness and dwarfness in pea plant are inherited independently.
Reason (R): When a homozygous tall pea plant is crossed with a homozygous dwarf pea plant, medium height plants are obtained in F1 generation.
SECTION B: SHORT ANSWER QUESTIONS (3 Marks Each)
15. Explain the terms: (i) Gene (ii) Heredity (iii) Variation.
16. In a monohybrid cross between a pure tall pea plant (TT) and a pure dwarf pea plant (tt), what is the F1 generation and F2 generation ratio? Show with a Punnett square.
17. How is the sex of the child determined in human beings? Explain with a diagram.
18. How do genes control characteristics (traits)? Explain with an example.
19. Differentiate between acquired and inherited traits. Give one example of each.
20. Different species use different strategies to determine sex of a newborn individual. It can be environmental or genetic. Justify this statement with examples.
SECTION C: LONG ANSWER QUESTIONS (5 Marks Each)
21. A cross was made between pure breeding pea plants, one with round and green seeds (RRyy) and the other with wrinkled and yellow seeds (rrYY).
(i) Write the genotype of F1 progeny.
(ii) What will be the phenotype of F1 progeny?
(iii) Write the phenotypic ratio of F2 progeny obtained by self-pollination of F1 plants.
(iv) Mention one dominant and one recessive trait seen in this cross.
22. Explain Mendel's Law of Dominance and Law of Segregation with suitable examples.
SECTION D: CASE STUDY (4 Marks)
23. Read the following text and answer the questions:
Mendel worked on garden peas and discovered the fundamental laws of inheritance. He observed that traits are inherited as independent units. He performed monohybrid and dihybrid crosses to arrive at his conclusions.

(i) Why did Mendel choose the Garden Pea plant for his experiments? (Give 1 reason). (1 Mark)
(ii) Define phenotype. (1 Mark)
(iii) If a tall plant (Tt) is crossed with a dwarf plant (tt), what fraction of the offspring will be dwarf? Show the cross. (2 Marks)
24. Read the following text and answer the questions:
In human beings, the sex of the individual is genetically determined. Sex determination is the process by which the sex of a person is established. Males have XY sex chromosomes, and females have XX sex chromosomes.

(i) What is the probability of a couple having a girl child? (1 Mark)
(ii) Who is responsible for the sex of the child - mother or father? (1 Mark)
(iii) How many pairs of chromosomes are present in human beings? How many are autosomes and how many are sex chromosomes? (2 Marks)
"All the best!"