Class 10 Science Chapter 5 Question Answers - Life Processes

Q1: Define Nutrition and Explain the Different Modes of Nutrition in Plants.
Ans: Nutrition is the process by which organisms obtain and utilize nutrients for growth, energy, and maintenance of life. In plants, there are two main modes of nutrition: autotrophic and heterotrophic.

• Autotrophic Nutrition: Plants synthesize their own food using sunlight, water, and carbon dioxide through photosynthesis. The chemical equation for photosynthesis is:
  6 CO₂ + 6 H₂O + sunlight → C₆H₁₂O₆ + 6 O₂
• Heterotrophic Nutrition: Some plants are partially or fully heterotrophic, meaning they obtain nutrients from other organisms. Examples include carnivorous plants that capture insects and absorb nutrients and saprophytic plants that decompose dead organic matter to absorb nutrients.

Q2: Describe the Role of Enzymes in Digestion with an Example.
Ans: Enzymes are biological catalysts that speed up chemical reactions in living organisms. In digestion, enzymes play a crucial role in breaking down complex food molecules into simpler forms that can be absorbed. For example, the enzyme pepsin is produced in the stomach and helps in the digestion of proteins.
The reaction involving pepsin can be represented as:
Proteins + HCl → Peptides

Q3: Explain the Process of Respiration in Humans.
Ans: Respiration is the process by which cells obtain energy from glucose molecules. In humans, respiration occurs in three main stages:

• Glycolysis: Glucose is broken down into pyruvate in the cytoplasm.
• Citric Acid Cycle: Pyruvate is further broken down in the mitochondria, releasing carbon dioxide and producing energy-rich molecules.
• Electron Transport Chain: Energy-rich molecules from the previous stages are used to generate ATP, the cell's primary energy currency.

Q4: Discuss the Importance of Transportation of Water in Plants.
Ans: Transportation of water in plants occurs through the process of transpiration and is essential for various reasons:

• Nutrient Transport: Water carries essential minerals dissolved in soil to different parts of the plant.
• Cooling Effect: Transpiration cools the plant by releasing excess heat through evaporation.
• Maintaining Turgidity: Water maintains cell turgidity, preventing wilting and maintaining plant structure.

Q5: Elaborate on the Excretory System in Humans and its Role in Homeostasis.
Ans: The excretory system in humans eliminates waste products and helps maintain internal balance (homeostasis). Key components include the kidneys, ureters, bladder, and urethra.

• Filtration: Blood is filtered in the kidneys, removing waste and forming urine.
• Reabsorption: Useful substances like glucose and water are reabsorbed into the bloodstream.
• Secretion: Additional waste products are actively secreted into the urine.
• Homeostasis: The excretory system regulates water and electrolyte balance, maintaining proper blood pressure and pH levels.

Q6: Explain the Process of Photosynthesis in Plants and its Significance.
Ans: Photosynthesis is the process by which green plants synthesize their own food using sunlight. It involves the conversion of carbon dioxide and water into glucose and oxygen, with the help of chlorophyll. The equation for photosynthesis is:
6 CO₂ + 6 H₂O + sunlight → C₆H₁₂O₆ + 6 O₂
Photosynthesis is crucial as it produces food, releases oxygen into the atmosphere, and forms the basis of the food chain.

Q7: Describe the Mechanism of Blood Circulation in Humans and its Role in Nutrient Transport.
Ans: Blood circulation involves the heart pumping blood through a network of blood vessels. Deoxygenated blood is pumped to the lungs for oxygenation, while oxygenated blood is circulated to body tissues. Nutrients obtained from digested food are transported via the bloodstream to various cells for energy, growth, and repair.

Q8: Discuss the Role of Endocrine Glands in the Human Body with an Example.
Ans: Endocrine glands secrete hormones that regulate various bodily functions. For instance, the thyroid gland produces thyroxine, which controls metabolism. Insufficient thyroxine secretion can lead to disorders like hypothyroidism, affecting energy levels and overall health.

Q9: Explain the Reproductive System in Plants and How Pollination Takes Place.
Ans: In plants, reproduction occurs through the formation of flowers and subsequent pollination. Pollination is the transfer of pollen from the male anther to the female stigma. This can be achieved by various agents, such as wind, water, insects, or birds, facilitating fertilization and seed formation.

Q10: Elaborate on the Nervous System in Humans and its Role in Coordination and Response.
Ans: The nervous system coordinates and controls body activities. It comprises the central nervous system (brain and spinal cord) and peripheral nervous system. Sensory neurons detect stimuli and transmit signals to the central nervous system, which processes information and sends motor responses. This system enables rapid reactions to external and internal changes, ensuring survival and adaptation.