What are the different modes of nutrition in plants and animals?

Nutrition is the process by which organisms obtain food for energy and growth. Plants are autotrophs — they prepare their own food through photosynthesis using sunlight, carbon dioxide, and water. Animals are heterotrophs, meaning they depend on other organisms for food. Heterotrophic nutrition is further divided into: holozoic nutrition (ingestion of whole food like in humans), saprophytic nutrition (breaking down dead organic matter, as in fungi and bacteria), and parasitic nutrition (living on or inside a host and absorbing nutrients from it, like tapeworms). Some organisms like Euglena can perform both autotrophic and heterotrophic nutrition depending on the conditions. Understanding these modes of nutrition explains the diverse ways life sustains itself across different environments and ecological niches.

How does photosynthesis work and what are the conditions required for it?

Photosynthesis is the process by which green plants and some microorganisms convert light energy into chemical energy stored as glucose. The general equation is: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂. The four raw materials required are carbon dioxide (from air through stomata), water (absorbed from soil through roots), chlorophyll (the green pigment in chloroplasts), and sunlight. The process occurs in two stages — the light reaction (in the grana of chloroplasts, where water is split and oxygen is released) and the dark reaction or Calvin cycle (in the stroma, where CO₂ is fixed into glucose using ATP and NADPH). Factors affecting photosynthesis include light intensity, CO₂ concentration, water availability, and temperature. Leaves are specially adapted with a large surface area, thin structure, and stomata to maximise photosynthesis.

What is the difference between aerobic and anaerobic respiration?

Respiration is the process by which organisms break down food to release energy. Aerobic respiration occurs in the presence of oxygen and takes place in the mitochondria. Glucose is completely broken down to carbon dioxide and water, releasing a large amount of energy (36–38 ATP molecules). The equation is: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy. Anaerobic respiration occurs in the absence of oxygen, releasing much less energy (only 2 ATP). In yeast, it produces ethanol and CO₂ (fermentation), while in our muscle cells during intense exercise it produces lactic acid. The buildup of lactic acid causes muscle cramps. Anaerobic respiration is less efficient but allows organisms to function temporarily without oxygen, which is crucial during vigorous physical activity.

How does the human circulatory system work?

The human circulatory system transports nutrients, oxygen, hormones, and waste products throughout the body. It consists of the heart, blood vessels (arteries, veins, capillaries), and blood. The heart is a four-chambered muscular organ divided into the right atrium and right ventricle (which handle deoxygenated blood) and the left atrium and left ventricle (which handle oxygenated blood). Deoxygenated blood from the body enters the right atrium, goes to the right ventricle, and is pumped to the lungs for oxygenation (pulmonary circulation). Oxygenated blood returns to the left atrium, enters the left ventricle, and is pumped to the rest of the body (systemic circulation). Arteries carry blood away from the heart under high pressure, veins return blood to the heart, and capillaries enable exchange of substances with body cells.

What is excretion and how do kidneys perform it in humans?

Excretion is the process of removing metabolic waste products from the body to maintain internal balance (homeostasis). In humans, the main excretory organ is the kidney. Each kidney contains millions of tiny filtering units called nephrons. Blood under pressure enters the nephron through the glomerulus — a cluster of capillaries inside the Bowman's capsule. Filtration occurs here, allowing water, glucose, urea, salts, and amino acids to pass through while retaining blood cells and proteins. As the filtrate passes through the renal tubule, useful substances like glucose, water, and salts are selectively reabsorbed back into the blood. The remaining waste, now called urine (containing urea, excess salts, and water), is collected in the renal pelvis, flows to the ureter, stored in the urinary bladder, and expelled through the urethra.

NCERT Solutions for Class 10 Science Chapter 5 Life Processes

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NCERT Solutions for Class 10 Science Chapter 5: Life Processes

Life Processes is the bridge between the physical sciences and biology in Class 10 Science, and it is one of the most scoring chapters for students who understand the underlying mechanisms. The chapter covers six fundamental life processes — nutrition, respiration, transportation, excretion, and related sub-processes — that are essential for the survival of all living organisms. NCERT Solutions for Class 10 Science Chapter 5 on Myclass24 have been crafted to explain each biological process step by step, making even complex concepts like the double circulation in humans or the mechanism of stomatal exchange accessible to students at every learning level.

Diagrams play a huge role in this chapter — the human heart, nephron structure, cross-section of a leaf — and Myclass24 guides students on how to draw and label these correctly in board exams. Whether you are studying for your first unit test or final CBSE board, the Chapter 5 solutions on Myclass24 ensure you are thoroughly prepared.

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Chapter 5 Quick Revision: Life Processes — Facts and Tables

Life Processes becomes much clearer when each process is studied in comparison with others. The following structured tables cover all major topics in Chapter 5 and are optimised for mobile screens so students can revise anywhere.

Overview of Life Processes

Life Process	Definition	Organ/System Involved
Nutrition	Obtaining and using food for energy and growth	Digestive system
Respiration	Breaking down food to release energy (ATP)	Lungs, mitochondria
Transportation	Moving substances to and from cells	Circulatory / vascular system
Excretion	Removing metabolic waste from the body	Kidneys, lungs, skin

Autotrophic vs Heterotrophic Nutrition

Feature	Autotrophic	Heterotrophic
Source of food	Synthesise their own food	Depend on other organisms
Process	Photosynthesis / Chemosynthesis	Ingestion, digestion, absorption
Examples	Green plants, algae, cyanobacteria	Humans, animals, fungi
Energy source	Sunlight or chemical energy	Organic food from environment
Chlorophyll needed	Yes (for photosynthesis)	No

Photosynthesis: What Happens Inside a Leaf?

Photosynthesis is the process by which green plants convert light energy into chemical energy (glucose) using carbon dioxide and water. The overall equation is: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂. It takes place in the chloroplasts, specifically in the thylakoid membranes (light reactions) and the stroma (dark reactions/Calvin cycle). Stomata are tiny pores on the leaf surface through which CO₂ enters and O₂ exits. Guard cells regulate the opening and closing of stomata.

Aerobic vs Anaerobic Respiration

Feature	Aerobic Respiration	Anaerobic Respiration
Oxygen required	Yes	No
Location	Cytoplasm + Mitochondria	Cytoplasm only
End products	CO₂ + H₂O + energy (38 ATP)	Ethanol / Lactic acid + CO₂ + energy (2 ATP)
Energy released	High (2870 kJ/mol)	Low (210 kJ/mol)
Occurs in	Most plants and animals	Yeast, muscles during exercise

Human Circulatory System — Key Facts

Component	Function	Type of Blood Carried
Heart	Pumps blood throughout the body	Both oxygenated & deoxygenated
Arteries	Carry blood away from heart	Oxygenated (except pulmonary artery)
Veins	Carry blood toward heart	Deoxygenated (except pulmonary vein)
Capillaries	Exchange of gases and nutrients	Mixed
Platelets	Clotting of blood at wound site	N/A

Excretion in Humans: The Role of the Kidney

The kidneys filter blood through a process called ultrafiltration. Each kidney contains about 1 million nephrons, which are the functional units of the kidney. Blood enters the glomerulus (a network of capillaries), where filtration occurs. Useful substances like glucose, amino acids, and water are reabsorbed in the tubule. The remaining fluid becomes urine, which travels to the urinary bladder via ureters and is expelled through the urethra. In cases of kidney failure, patients undergo dialysis — a process that artificially filters blood using a dialysis machine.

Board Exam Marks Distribution: Chapter 5

Topic	Expected Marks	Question Type
Photosynthesis	3–5 marks	Diagram + explanation
Respiration types	3 marks	Comparison table / short answer
Human circulatory system	5 marks	Diagram + function
Excretion and nephron	3–5 marks	Diagram + labelling
Nutrition modes	2–3 marks	MCQ + short answer