The topic of 'Heredity' in Class 10 Science (Biology) is an important part of the Science subject and can be that one chapter which can get you easy marks
if you prepare right. This topic deals with how traits are passed from parents to offspring and explains the basic principles of inheritance. For students who are looking for quick notes on this important topic, here are a few pointers that can help you do quick revision sessions efficiently. Background:
- Sexually reproducing individuals show clear variations.
- Inheritance ensures a basic body design with minor changes in each generation.
- Environmental selection of useful variations drives evolution.
- Heredity is the transmission of traits from parents to offspring.
Monohybrid cross:
Study of inheritance of a single pair of contrasting traits (e.g., tall and dwarf plants in pea plants).
- Each trait is inherited independently
- Variants from parents’ generation were observe.
Sex determination:
Animals use different sex-determination strategies. In some reptiles, temperature decides sex
Sex Determination in Humans by sex chromosomes:
- Females: XX, Males: XY
- During reproduction: Female always contributes an X chromosome, Male contributes either an X or Y chromosome. If the offspring inherits an X from the father, it is female (XX). If it inherits a Y, it is male (XY)
Sample questions
Very Short Answer Questions (1 mark)
- Define heredity.
- What is meant by a gene?
- Name the scientist who proposed the laws of inheritance.
- What is an allele?
- Write the chromosomal combination of a human female.
Short Answer Questions (2 marks)
- What is meant by variation? State one advantage of variation.
- Differentiate between inherited traits and acquired traits.
- What is a dominant trait? Give one example.
- Why are acquired traits not inherited?
- State Mendel’s Law of Segregation.
Short Answer Questions (3 marks)
- Explain Mendel’s monohybrid cross with the help of a Punnett square.
- Distinguish between genotype and phenotype.
- How is sex determined in human beings? Explain with a diagram.
- Write three differences between asexual and sexual reproduction with respect to heredity.
- What are homologous chromosomes? State their role in inheritance.
Long Answer Questions (5 marks)
- Describe Mendel’s experiments on inheritance of traits in pea plants.
- Explain Mendel’s dihybrid cross and state the Law of Independent Assortment.
- How do genes control the expression of traits? Explain with an example.
- Explain the mechanism of inheritance in human beings.
- “Variation is important for the survival of species.” Justify this statement.
Case-Based / Competency-Based Questions (4–5 marks)
- A pea plant with round seeds is crossed with a pea plant having wrinkled seeds.
- (a) Identify the dominant trait.
- (b) Draw the Punnett square for F₁ generation.
- (c) What will be the phenotype of the F₁ progeny?
- (d) State the law illustrated by this cross.
- In humans, a child has blood group O while both parents have blood group A.
- (a) How is this possible?
- (b) Write the possible genotypes of the parents.
- (c) Name the type of inheritance shown.
This is one of the topics from CBSE Class 10 Science syllabus that will also help you after you complete your schooling.
