Subject: Science | Class: 10 | Chapter 6
🧭 Introduction
Living organisms perform several vital functions such as nutrition, respiration, transportation, and excretion to survive. These functions together are called Life Processes. This chapter helps students understand how the human body and plants carry out these processes in an organized and coordinated manner.
Q1. The kidneys in human beings are a part of the system for —
(a) nutrition (b) respiration (c) excretion (d) transportation
Answer: ✅ (c) excretion
Kidneys remove waste products and excess substances from the blood in the form of urine. This process is called excretion.
Q2. The xylem in plants is responsible for —
(a) transport of water (b) transport of food (c) transport of amino acids (d) transport of oxygen
Answer: ✅ (a) transport of water
Xylem transports water and minerals from roots to different parts of the plant.
Q3. The autotrophic mode of nutrition requires —
(a) carbon dioxide and water (b) chlorophyll (c) sunlight (d) all of the above
Answer: ✅ (d) all of the above
Plants need CO₂, water, sunlight, and chlorophyll to prepare food by photosynthesis.
Q4. The breakdown of pyruvate to give carbon dioxide, water, and energy takes place in —
(a) cytoplasm (b) mitochondria (c) chloroplast (d) nucleus
Answer: ✅ (b) mitochondria
Mitochondria are known as the powerhouses of the cell, where aerobic respiration occurs.
Q5. How are fats digested in our bodies? Where does this process take place?
Answer:
Fats are digested in the small intestine. Bile from the liver breaks large fat globules into smaller ones (emulsification). Then, lipase enzyme from the pancreas converts fats into fatty acids and glycerol.
Q6. What is the role of saliva in the digestion of food?
Answer:
Saliva, secreted by salivary glands, contains amylase enzyme, which breaks down starch into maltose (sugar). It also helps in lubricating and softening food for swallowing.
Q7. What are the necessary conditions for autotrophic nutrition and what are its by-products?
Answer:
Necessary conditions:
- Sunlight
- Chlorophyll
- Carbon dioxide
- Water
By-products:
- Oxygen (O₂) and Glucose (C₆H₁₂O₆) are formed during photosynthesis.
Q8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Answer:
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| Oxygen Required | Yes | No |
| End Products | CO₂ + H₂O + Energy | Alcohol/Lactic acid + Energy |
| Occurs in | Mitochondria | Cytoplasm |
| Example | Humans, animals | Yeast, some bacteria |
Organisms using anaerobic respiration: Yeast, some bacteria, and muscle cells (temporarily).
Q9. How are the alveoli designed to maximise the exchange of gases?
Answer:
- Alveoli have a large surface area.
- Their walls are thin and surrounded by a dense network of capillaries.
These features help in the efficient exchange of oxygen and carbon dioxide between the lungs and blood.
Q10. What would be the consequences of a deficiency of haemoglobin in our bodies?
Answer:
Haemoglobin helps carry oxygen. Its deficiency leads to anaemia, causing fatigue, breathlessness, and pale skin due to insufficient oxygen supply to tissues.
Q11. Describe double circulation of blood in human beings. Why is it necessary?
Answer:
In humans, blood passes through the heart twice during each complete circulation:
- Pulmonary circulation – from heart to lungs and back.
- Systemic circulation – from heart to body and back.
This ensures oxygenated and deoxygenated blood do not mix, maintaining efficient oxygen supply.
Q12. What are the differences between the transport of materials in xylem and phloem?
Answer:
| Feature | Xylem | Phloem |
|---|---|---|
| Material Transported | Water and minerals | Food (sugars) |
| Direction | Upward only | Upward and downward |
| Type of Transport | Passive | Active |
| Energy Required | No | Yes |
Q13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
Answer:
| Function | Alveoli | Nephrons |
|---|---|---|
| Function | Exchange of gases | Filtration of blood |
| Structure | Thin-walled sacs surrounded by capillaries | Tubular structures with Bowman’s capsule and tubule |
| Process | Oxygen diffuses in, CO₂ diffuses out | Filters waste to form urine |
| End Product | Oxygenated blood | Urine |
- Chemical Reactions and Equations
- Acids, Bases and Salts
- Metals and Non‑Metals
- Carbon and Its Compounds
- Life Processes
- Control and Coordination
- How Do Organisms Reproduce?
- Heredity and Evolution
- Light – Reflection and Refraction
- The Human Eye and the Colourful World
- Electricity
- Magnetic Effects of Electric Current
- Our Environment
🧩 Conclusion
The study of Life Processes gives insight into how living organisms maintain and regulate body functions such as nutrition, respiration, transportation, and excretion — all essential for survival and maintaining homeostasis.
