WORKSHEET – CHAPTER 8: HEREDITY

SECTION A – MULTIPLE CHOICE QUESTIONS (20 MCQs)

  1. The branch of biology that deals with transmission of characters from parents to offspring is:
     a) Genetics
     b) Evolution
     c) Ecology
     d) Cytology

  2. Mendel is known as:
     a) Father of Biology
     b) Father of Genetics
     c) Father of Evolution
     d) Father of Heredity

  3. A specific segment of DNA that controls a particular trait is called:
     a) Chromosome
     b) Gene
     c) Gamete
     d) Protein

  4. Alternative forms of a gene are called:
     a) Characters
     b) Traits
     c) Alleles
     d) Genotypes

  5. In Mendel’s monohybrid cross, the F₂ ratio is:
     a) 1:2:1
     b) 3:1
     c) 9:3:3:1
     d) 1:1

  6. Tall (T) is dominant over dwarf (t). Tt × Tt gives dwarf plants in the ratio:
     a) 50%
     b) 25%
     c) 75%
     d) 0%

  7. Genotype of pure tall plant is:
     a) Tt
     b) tt
     c) TT
     d) T

  8. Sex of a child is determined by:
     a) X chromosome of mother
     b) X chromosome of father
     c) Y chromosome of father
     d) Hormones

  9. A human male has:
     a) XX
     b) XY
     c) XO
     d) YY

  10. A human female produces:
     a) Only X gametes
     b) Only Y gametes
     c) Both X and Y
     d) XY gametes

  11. A test cross helps to determine:
     a) Sex
     b) Age
     c) Genotype
     d) Hormones

  12. Passing of traits from parents to offspring is called:
     a) Mutation
     b) Evolution
     c) Inheritance
     d) Variation

  13. Variations arise due to:
     a) Environmental factors
     b) DNA copying errors
     c) Sexual reproduction
     d) All of these

  14. The physical appearance of an organism is called:
     a) Genotype
     b) Phenotype
     c) Trait
     d) Chromosome

  15. The law of segregation states that:
     a) Alleles blend
     b) Alleles separate during gamete formation
     c) Dominant alleles vanish
     d) Recessive alleles mutate

Case-Based MCQs

Read the case and answer Q16–20:

Mendel crossed pure tall (TT) with pure dwarf (tt). F₁ were all tall (Tt). F₂ showed 3 tall : 1 dwarf.

  1. Genotype of dwarf F₂ plants:
     a) TT
     b) Tt
     c) tt
     d) T_

  2. Ratio of genotype in F₂:
     a) 3:1
     b) 1:2:1
     c) 2:1:1
     d) 4:0

  3. Height in pea plant is:
     a) Sex-linked trait
     b) Monogenic trait
     c) Acquired trait
     d) Multiple allele trait

  4. Dominant trait in Mendel’s cross:
     a) Dwarf
     b) Hybrid
     c) Tall
     d) Recessive

  5. F₁ individuals are:
     a) Homozygous
     b) Heterozygous
     c) Pure tall
     d) Mutation

SECTION B – ASSERTION & REASON (10 Questions)

  1. A: Sex of child is determined by father.
     R: Father produces both X and Y chromosomes.

  2. A: Variations occur more in sexually reproducing organisms.
     R: DNA comes from two parents.

  3. A: Tall trait appears in F₁ generation of Mendel’s cross.
     R: Tall allele is dominant.

  4. A: Alleles segregate during gamete formation.
     R: Gametes carry only one allele of a gene.

  5. A: Acquired traits are not inherited.
     R: They do not cause changes in DNA.

  6. A: Phenotype can differ even if genotype is same.
     R: Environment influences phenotype.

  7. A: Dihybrid cross shows 9:3:3:1 ratio.
     R: Traits assort independently.

  8. A: Males have XY chromosomes.
     R: Y chromosome determines maleness.

  9. A: Genes are located on chromosomes.
     R: Chromosomes are made of DNA.

  10. A: A test cross helps identify genotype.
     R: It always uses a homozygous recessive parent.

SECTION C – ONE-WORD / VERY SHORT ANSWERS (10)

  1. Define heredity.
  2. What is a gene?
  3. Name alleles of tall and dwarf trait in pea plant.
  4. What is genotype?
  5. What is phenotype?
  6. State Mendel’s first law.
  7. Define dominant trait.
  8. Why are Male responsible for sex of child?
  9. What is variation?
  10. Define homozygous.

SECTION D – SHORT ANSWER QUESTIONS (8)

  1. Explain Mendel’s monohybrid cross using a Punnett square.
  2. Distinguish between dominant and recessive traits.
  3. Why is sex of a child determined by the father, not mother?
  4. Explain the law of segregation with an example.
  5. What is the role of chromosomes in heredity?
  6. Explain variation and its importance.
  7. Describe sex determination mechanism in humans.
  8. What is a test cross? Explain with example.

SECTION E – LONG ANSWER QUESTIONS (5)

Q1. (Mendel’s Experiments – 5 Marks)

(a) Explain Mendel’s monohybrid cross in detail with diagram.
 (b) Write the genotype and phenotype ratios of F₂ generation.
 (c) State the law derived from this experiment.

Q2. (Genes, Alleles, and Variations – 5 Marks)

(a) Define gene and allele.
 (b) Explain how variations are produced during reproduction.
 (c) Why are variations important for survival?
 (d) Give two differences between genotype and phenotype.

Q3. (Sex Determination – 5 Marks)

(a) Explain XX–XY mechanism of sex determination in humans.
 (b) Why is the father responsible for sex of child?
 (c) Make a Punnett square for sex determination.
 (d) Why can’t mother determine sex of child?

Q4. (Dihybrid Concept Only, Without Evolution) – 5 Marks)

(a) Explain Mendel’s dihybrid cross briefly.
 (b) Derive the F₂ ratio 9:3:3:1.
 (c) State the law of independent assortment.
 (d) Why does independent assortment produce new combinations?

Q5. (Case-Based Heredity – 5 Marks)

A pure tall round (TTRR) pea plant is crossed with pure dwarf wrinkled (ttrr).

(a) What will be genotype and phenotype of F₁?
 (b) Show F₂ generation using Punnett square.
 (c) How many types of phenotypes appear in F₂?
 (d) Why are new combinations produced in F₂?

 

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