Biology is one of the most important subjects for Class 10 students, especially for those preparing for their Board Exams. It carries significant weightage in the Science paper, and understanding the important chapters and topics can help you score well. In this blog post, we will cover all the important Biology chapters, key concepts, diagrams, and exam-focused topics that you should revise thoroughly.

Table of Contents

Class 10 Biology Important Topics for Exam | Key Notes & MCQs

Why Biology is Important in Class 10?

Biology is not only scoring but also easy to understand as most concepts are related to our daily life. Questions are often diagram-based, definition-based, or application-oriented. A good strategy is to focus on important chapters and revise NCERT line by line as most questions come directly from it.

Important Chapters of Class 10 Biology (Exam Point of View)

1. Life Processes

This is one of the most important chapters and frequently asked in exams.

Key Topics to Revise:
- Nutrition in plants (autotrophic, heterotrophic, photosynthesis equation).
- Human nutrition (digestive system, enzymes, peristalsis).
- Respiration (aerobic and anaerobic respiration, differences, ATP).
- Human respiratory system (structure, alveoli, exchange of gases).
- Transportation in plants (xylem & phloem).
- Human circulatory system (heart structure, double circulation, blood vessels, blood components).
- Excretion in humans (kidney structure, nephron diagram & functions).
Diagrams to Practice:
- Human digestive system
- Human respiratory system
- Human heart (with chambers and valves)
- Nephron

2. Control and Coordination

This chapter deals with how organisms respond to stimuli.

Key Topics to Revise:
- Nervous system in humans (structure of neuron, reflex action, reflex arc).
- Brain structure and functions (cerebrum, cerebellum, medulla oblongata).
- Hormones in animals (pituitary gland, thyroid, insulin, adrenaline).
- Coordination in plants (tropism, plant hormones like auxin, gibberellin).
Diagrams to Practice:
- Structure of neuron
- Human brain with labeling
- Reflex arc

3. How Do Organisms Reproduce?

Questions from this chapter are common in board exams.

Key Topics to Revise:
- Asexual reproduction (binary fission, budding, fragmentation, regeneration, spore formation, vegetative propagation).
- Sexual reproduction in plants (pollination, fertilization, double fertilization).
- Reproduction in humans (male & female reproductive system, gamete formation, fertilization, zygote formation).
- Reproductive health (contraceptive methods – barrier, surgical, chemical, natural).
Diagrams to Practice:
- Binary fission in Amoeba
- Budding in Hydra
- Human male & female reproductive systems
- Longitudinal section (LS) of flower

4. Heredity and Evolution

This is both conceptual and factual.

Key Topics to Revise:
- Mendel’s experiments (monohybrid and dihybrid cross, laws of inheritance).
- Dominant and recessive traits.
- Sex determination in humans (XX–XY mechanism).
- Evolution (fossils, homologous & analogous organs, adaptive radiation, Darwin’s theory).
Diagrams to Practice:
- Mendel’s cross (Punnett square)
- Sex determination diagram

5. Our Environment

This chapter is short but very scoring.

Key Topics to Revise:
- Ecosystem components (producers, consumers, decomposers).
- Food chains and food webs.
- Ozone layer depletion & its effects.
- Biological magnification (definition & examples).
Diagrams to Practice:
- Food chain example
- Pyramids of energy

6. Sustainable Management of Natural Resources

This is more theory-based and often has 3–5 mark questions.

Key Topics to Revise:
- 5 R’s of sustainable development (Refuse, Reduce, Reuse, Repurpose, Recycle).
- Conservation of forests and wildlife.
- Management of water resources (rainwater harvesting, dams).
- Coal and petroleum (judicious use).
Case Studies to Revise:
- Chipko movement
- Water conservation methods in India

Weightage of Biology in Class 10 Science Exam

Generally, Biology carries 20–25 marks in the Science Board paper. Some questions are 1 mark (objective/definition-based), 3 marks (short answers), and 5 marks (long answers/diagrams).

Tips to Score High in Biology

Revise NCERT thoroughly (most questions come directly).
Practice labeled diagrams (2–3 marks often come from diagrams).
Make short notes with flowcharts for quick revision.
Solve previous years’ question papers and sample papers.
Use mnemonics for remembering examples and processes.

Most Important Diagrams for Class 10 Biology Exam

Human digestive system
Human heart
Human respiratory system
Nephron
Structure of neuron
Reflex arc
Human brain
Male & female reproductive system
Longitudinal section of flower
Mendel’s cross (Punnett square)

Class 10 Biology – 20 Important Objective Questions (MCQs)

1. Which part of the nephron is responsible for filtration of blood?

(a) Loop of Henle
(b) Collecting duct
(c) Ureter
(d) Bowman’s capsule
Answer: (d) Bowman’s capsule

2. Which enzyme is secreted in the stomach for protein digestion?

(a) Amylase
(b) Lipase
(c) Pepsin
(d) Trypsin
Answer: (c) Pepsin

3. Which blood vessel carries oxygenated blood from lungs to heart?

(a) Pulmonary artery
(b) Pulmonary vein
(c) Aorta
(d) Vena cava
Answer: (b) Pulmonary vein

4. The energy currency of the cell is:

(a) DNA
(b) RNA
(c) ATP
(d) Protein
Answer: (c) ATP

5. The functional unit of the nervous system is:

(a) Brain
(b) Spinal cord
(c) Nephron
(d) Neuron
Answer: (d) Neuron

6. Which part of the brain controls posture and balance?

(a) Cerebrum
(b) Cerebellum
(c) Medulla oblongata
(d) Pons
Answer: (b) Cerebellum

7. In which part of the plant does photosynthesis occur?

(a) Root
(b) Stem
(c) Leaf
(d) Flower
Answer: (c) Leaf

8. Which hormone regulates the sugar level in blood?

(a) Adrenaline
(b) Thyroxine
(c) Insulin
(d) Estrogen
Answer: (c) Insulin

9. Pollination by insects is called:

(a) Anemophily
(b) Hydrophily
(c) Entomophily
(d) Zoophily
Answer: (c) Entomophily

10. In Amoeba, reproduction occurs by:

(a) Budding
(b) Binary fission
(c) Fragmentation
(d) Spore formation
Answer: (b) Binary fission

11. The chromosome number in human gametes is:

(a) 23 pairs
(b) 46
(c) 23
(d) 44
Answer: (c) 23

12. Which law of Mendel is also called the Law of Purity of Gametes?

(a) Law of Segregation
(b) Law of Independent Assortment
(c) Law of Dominance
(d) Law of Variation
Answer: (a) Law of Segregation

13. Which of the following is an example of homologous organs?

(a) Wings of bat and wings of butterfly
(b) Forelimbs of human and wings of bat
(c) Wings of birds and wings of insects
(d) Fins of fish and flippers of whale
Answer: (b) Forelimbs of human and wings of bat

14. Which gas is mainly responsible for ozone depletion?

(a) Carbon dioxide
(b) Nitrous oxide
(c) Methane
(d) Chlorofluorocarbons (CFCs)
Answer: (d) Chlorofluorocarbons (CFCs)

15. Energy flow in an ecosystem is always:

(a) Cyclic
(b) Unidirectional
(c) Reversible
(d) Random
Answer: (b) Unidirectional

16. The movement of water through xylem is due to:

(a) Photosynthesis
(b) Transpiration pull
(c) Respiration
(d) Both (b) and root pressure
Answer: (d) Both (b) and root pressure

17. Which part of the flower develops into fruit?

(a) Ovary
(b) Ovule
(c) Stamen
(d) Petal
Answer: (a) Ovary

18. Which part of the human brain controls involuntary actions like heartbeat and breathing?

(a) Cerebellum
(b) Medulla oblongata
(c) Cerebrum
(d) Hypothalamus
Answer: (b) Medulla oblongata

19. The process by which plants lose extra water is called:

(a) Photosynthesis
(b) Respiration
(c) Transpiration
(d) Absorption
Answer: (c) Transpiration

20. The concept of “Survival of the fittest” was given by:

(a) Lamarck
(b) Mendel
(c) Darwin
(d) Wallace
Answer: (c) Darwin

Conclusion

Biology in Class 10 is not just about memorizing; it’s about understanding life processes. If you focus on the important topics, diagrams, and NCERT book, you can easily secure full marks in Biology. Prioritize the chapters mentioned above, practice diagrams daily, and revise definitions. This will ensure you stay confident and prepared for your exam.

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