Bihar Board Class 10 Biology Notes 2025 | Full Short Revision Guide with Important Questions

This article is designed for last-minute preparation, ensuring you get a clear idea of the important topics without confusion.

Bihar Board Class 10 Biology Notes 2025 | Full Short Revision Guide with Important Questions

Chapter 1: Life Processes

Biology begins with the study of life processes that occur in living organisms. These include nutrition, respiration, transportation, and excretion.

Nutrition

• Nutrition is the process of obtaining food and utilizing it for growth and energy.

• Types: Autotrophic (plants, make their own food by photosynthesis) and Heterotrophic (animals, depend on others).

• Photosynthesis Equation:
  6CO2+6H2O→C6H12O6+6O26CO2​+6H2​O→C6​H12​O6​+6O2​

• Heterotrophic nutrition includes:

  • Holozoic (human)

  • Saprophytic (fungi)

  • Parasitic (plasmodium)

Respiration

• Breaking down of glucose to release energy.

• Types: Aerobic (with oxygen, releases more energy) and Anaerobic (without oxygen, releases less energy).

• Equation of aerobic respiration:
  C6H12O6+6O2→6CO2+6H2O+EnergyC6​H12​O6​+6O2​→6CO2​+6H2​O+Energy

Transportation in Human Beings

• Circulatory system consists of heart, blood, and blood vessels.

• Blood carries oxygen, nutrients, hormones, and wastes.

• Heart pumps blood in double circulation (systemic + pulmonary).

Transportation in Plants

• Xylem transports water and minerals.

• Phloem transports food by translocation.

Excretion

• Removal of nitrogenous waste.

• In humans: Excretory system = kidneys, ureters, urinary bladder, urethra.

• In plants: Gaseous wastes removed by stomata.

Chapter 2: Control and Coordination

This chapter deals with the nervous system, hormones, and coordination in plants.

Nervous System in Humans

• Consists of brain, spinal cord, and nerves.

• Brain parts:

  • Cerebrum (thinking, memory, intelligence)

  • Cerebellum (balance, posture)

  • Medulla oblongata (involuntary actions like breathing, heartbeat).

Coordination in Plants

• No nervous system but respond to stimuli.

• Tropic movements: phototropism (light), geotropism (gravity), hydrotropism (water).

• Plant hormones: auxins, gibberellins, cytokinins, abscisic acid.

Endocrine System in Humans

• Hormones secreted by glands regulate functions:

  • Pituitary (growth hormone)

  • Thyroid (thyroxine, metabolism)

  • Adrenal (adrenaline, emergency hormone)

  • Pancreas (insulin, sugar level control)

  • Sex hormones: testosterone (male), estrogen (female).

Chapter 3: How Do Organisms Reproduce?

Reproduction ensures continuity of species.

Asexual Reproduction

• Binary fission (Amoeba)

• Budding (Yeast, Hydra)

• Spore formation (Rhizopus)

• Vegetative propagation (Potato, Bryophyllum).

Sexual Reproduction in Plants

• Flowers are reproductive organs.

• Pollination: transfer of pollen from anther to stigma.

• Fertilization: fusion of male and female gametes.

• Seeds formed develop into new plants.

Sexual Reproduction in Humans

• Male reproductive system: testes (sperms, testosterone), vas deferens, penis.

• Female reproductive system: ovaries (eggs, estrogen, progesterone), fallopian tubes, uterus, vagina.

• Fertilization takes place in fallopian tube → zygote → embryo → fetus.

• Menstrual cycle: ~28 days, prepares uterus for pregnancy.

Chapter 4: Heredity and Evolution

Heredity

• Passing of traits from parents to offspring.

• Mendel’s experiments on pea plants → Laws of inheritance.

• Dominant and recessive traits.

• Example: Tall × Dwarf = all Tall (first generation).

Sex Determination in Humans

• XX = female, XY = male.

• Father decides sex of child.

Evolution

• Process of gradual change in living organisms.

• Charles Darwin: Theory of Natural Selection.

• Fossils, homologous organs, and embryology give evidence of evolution.

Chapter 5: Our Environment

Ecosystem

• Interaction between living (biotic) and non-living (abiotic) components.

• Example: Pond ecosystem, forest ecosystem.

Food Chain and Food Web

• Food chain: sequence of organisms where one is eaten by another.
  Example: Grass → Grasshopper → Frog → Snake → Eagle.

• Food web: interconnected food chains.

Energy Flow in Ecosystem

• Follows 10% law (only 10% energy transferred to next level).

Environmental Problems

• Ozone layer depletion due to CFCs.

• Pollution (air, water, soil).

• Waste management: reduce, reuse, recycle.

Chapter 6: Sustainable Management of Natural Resources

Why Manage Resources?

• Natural resources are limited and need sustainable use.

Forests and Wildlife

• Forests provide oxygen, raw materials, regulate climate.

• Deforestation leads to soil erosion, loss of biodiversity.

Water Resources

• Water conservation methods: rainwater harvesting, dams.

Coal and Petroleum

• Non-renewable resources, should be used judiciously.

Reduce, Reuse, Recycle

• Key principle of sustainable development.

Exam-Oriented Key Notes

• Life Processes: Focus on diagrams of digestive system, heart, nephron.

• Control and Coordination: Learn brain structure, plant hormones.

• Reproduction: Revise diagrams of flower, human reproductive system.

• Heredity: Solve Mendel’s cross examples.

• Environment: Remember 10% law, ozone depletion.

• Sustainable Management: Prepare short notes on water conservation.

Tips for Quick Revision Before Exams

1. Revise NCERT textbook diagrams carefully.

2. Learn definitions and scientific terms.

3. Practice previous year Bihar Board question papers.

4. Focus on frequently asked questions like photosynthesis, Mendel’s experiment, menstrual cycle, ecosystem, 10% law.

Important Objective Questions for Bihar Board Class 10 Biology

Q1. Which process in plants is responsible for food production?

a) Respiration
b) Photosynthesis
c) Transpiration
d) Excretion

Answer: b) Photosynthesis – Plants prepare their own food using carbon dioxide, water, and sunlight.

Q2. The functional unit of the kidney is called?

a) Nephron
b) Neuron
c) Alveoli
d) Glomerulus

Answer: a) Nephron – It helps in filtration of blood and removal of nitrogenous waste.

Q3. Which part of the brain controls balance and posture?

a) Cerebrum
b) Medulla oblongata
c) Cerebellum
d) Pons

Answer: c) Cerebellum – Responsible for body balance and coordination of muscles.

Q4. Which of the following is NOT a plant hormone?

a) Auxin
b) Insulin
c) Gibberellin
d) Cytokinin

Answer: b) Insulin – It is a human hormone secreted by pancreas, not a plant hormone.

Q5. In humans, fertilization occurs in which organ?

a) Uterus
b) Ovary
c) Vagina
d) Fallopian tube

Answer: d) Fallopian tube – The sperm fuses with the egg in the fallopian tube.

Q6. Which scientist is known as the Father of Genetics?

a) Darwin
b) Lamarck
c) Mendel
d) Watson

Answer: c) Mendel – He explained inheritance of traits using pea plant experiments.

Q7. The sex of a child is determined by?

a) Mother’s egg
b) Father’s sperm
c) Both equally
d) Hormones

Answer: b) Father’s sperm – Sperm carries X or Y chromosome, deciding gender.

Q8. The 10% law of energy transfer was proposed by?

a) Charles Darwin
b) Lindeman
c) Mendel
d) Lamarck

Answer: b) Lindeman – Only 10% of energy is transferred from one trophic level to the next.

Q9. Ozone layer protects us from?

a) Infrared rays
b) Ultraviolet rays
c) Visible light
d) Cosmic rays

Answer: b) Ultraviolet rays – It prevents harmful UV radiation from reaching Earth.

Q10. Which of the following is a renewable resource?

a) Coal
b) Petroleum
c) Forests
d) Natural gas

Answer: c) Forests – They can be renewed through plantation and conservation.

Q11. Which organ in human beings filters nitrogenous waste?

a) Liver
b) Kidney
c) Lungs
d) Skin

Answer: b) Kidney – It filters urea, uric acid, and excess water from blood.

Q12. Which gas is released during photosynthesis?

a) CO₂
b) O₂
c) N₂
d) H₂

Answer: b) O₂ – Oxygen is released as a by-product of photosynthesis.

Q13. The site of gaseous exchange in humans is?

a) Trachea
b) Bronchi
c) Alveoli
d) Diaphragm

Answer: c) Alveoli – Tiny air sacs in lungs where exchange of oxygen and carbon dioxide takes place.

Q14. 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 – It carries oxygen-rich blood from lungs to left atrium.

Q15. Which mode of reproduction is common in bacteria?

a) Budding
b) Binary fission
c) Spore formation
d) Fragmentation

Answer: b) Binary fission – Bacteria reproduce asexually by dividing into two identical cells.

Q16. The male reproductive hormone is?

a) Estrogen
b) Progesterone
c) Testosterone
d) Insulin

Answer: c) Testosterone – It controls male reproductive functions and development of secondary sexual characters.

Q17. The process of transfer of pollen grains from anther to stigma is called?

a) Fertilization
b) Pollination
c) Germination
d) Hybridization

Answer: b) Pollination – It can be self or cross, leading to fertilization in plants.

Q18. Which organ controls reflex actions?

a) Brain
b) Spinal cord
c) Cerebellum
d) Medulla

Answer: b) Spinal cord – Reflex actions are quick and involuntary responses controlled by spinal cord.

Q19. Which structure in plants helps in transportation of food?

a) Xylem
b) Phloem
c) Stomata
d) Root hairs

Answer: b) Phloem – It transports prepared food from leaves to different parts of the plant.

Q20. Which of the following is an example of ex-situ conservation?

a) National park
b) Biosphere reserve
c) Zoo
d) Sanctuary

Answer: c) Zoo – In ex-situ conservation, animals are protected outside their natural habitat.

Conclusion

This Bihar Board Class 10 Biology Notes Short Revision Notes guide covers all chapters in detail, helping students prepare effectively for exams. With clear explanations, key points, and exam tips, students can use this article for last-minute revision and score well in the Biology section of the Science paper