Life Processes — Class 10 MCQs with Answers

Life Processes — important questions & MCQs with answers (Class 10 Science (Biology))

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   Which gas is released by green plants during photosynthesis?

   ACarbon dioxideBHydrogenCNitrogenDOxygen
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   Answer: Oxygen

   Explanation: Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Oxygen is the by-product.

2. Q2 of 6Easy

   Aerobic respiration produces:

   ALactic acidBEthanol + CO₂CCO₂ + H₂O + ATPDOnly ATP
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   Answer: CO₂ + H₂O + ATP

   Explanation: Glucose + O₂ → CO₂ + H₂O + energy (ATP). Anaerobic gives lactic acid (in muscles) or ethanol (in yeast).

3. Q3 of 6Medium

   In plants, water is transported upwards through the:

   APhloemBXylemCCambiumDCortex
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   Answer: Xylem

   Explanation: Xylem transports water and minerals from roots to leaves; phloem transports food.

4. Q4 of 6Medium

   Assertion (A): In plants, carbohydrates that are not used immediately are stored as glycogen. Reason (R): In photosynthesis, carbon dioxide and water are converted into carbohydrates in the presence of sunlight and chlorophyll.

   ABoth A and R are true and R is the correct explanation of ABBoth A and R are true but R is not the correct explanation of ACA is true but R is falseDA is false but R is true
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   Answer: A is false but R is true

   Explanation: A is false: plants store unused carbohydrates as starch; glycogen is the energy store in our body. R is true.

5. Q5 of 6Hard

   Largest artery in the human body is the:

   AVena cavaBPulmonary arteryCAortaDCarotid
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   Answer: Aorta

   Explanation: The aorta is the body's largest artery, carrying oxygenated blood away from the left ventricle to the whole body; the vena cava, by contrast, is a vein returning blood to the heart.

6. Q6 of 6Hard

   Assertion (A): In a healthy adult, more than 98% of the initial filtrate formed in the kidneys each day is re-absorbed. Reason (R): Glucose, amino acids, salts and a major amount of water are selectively re-absorbed in the kidney tubules.

   ABoth A and R are true and R is the correct explanation of ABBoth A and R are true but R is not the correct explanation of ACA is true but R is falseDA is false but R is true
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   Answer: Both A and R are true and R is the correct explanation of A

   Explanation: Both are true. About 180 L of filtrate forms daily but only 1–2 L is excreted, so about 178–179 L (over 98%) is re-absorbed; this happens because the tubules re-absorb water and useful substances.

Life Processes notes: key concepts (Class 10 Science (Biology))

The processes that together maintain life are nutrition, respiration, transportation and excretion. This chapter follows each through plants and humans, from photosynthesis and the alimentary canal to the double circulation of blood and the working of the nephron.

Life processes

The basic functions all living organisms must perform to stay alive — nutrition, respiration, transportation and excretion.

Autotrophic nutrition

Making one's own food from simple inorganic substances using sunlight, as green plants do in photosynthesis.

Photosynthesis

The conversion of carbon dioxide and water into glucose and oxygen using sunlight captured by chlorophyll.

Stomata

Tiny pores on the leaf surface, opened and closed by guard cells, through which gases are exchanged and water vapour is lost.

Heterotrophic nutrition

Obtaining food made by others — saprophytic from dead matter, parasitic from a living host, and holozoic by ingesting whole food.

Human digestive system

The alimentary canal from mouth to anus with associated glands, in which food is progressively broken down and absorbed.

Digestive enzymes

Salivary amylase acts on starch, pepsin on protein in acidic stomach conditions, and pancreatic and intestinal enzymes complete digestion.

Villi

Finger-like projections of the small intestine that greatly increase surface area for absorption of digested food into the blood.

Aerobic and anaerobic respiration

Aerobic respiration uses oxygen and releases much more energy; anaerobic respiration gives lactic acid in muscles or ethanol in yeast.

Human respiratory system

Air passes through nostrils, trachea and bronchi to the alveoli, whose thin walls and rich blood supply allow rapid gas exchange.

Transportation in humans

The heart pumps blood through arteries, veins and capillaries; arteries carry blood away from the heart and veins carry it back.

Double circulation

Blood passes through the heart twice in one complete cycle, keeping oxygenated and deoxygenated blood entirely separate.

Transportation in plants

Xylem carries water and minerals upward by transpiration pull, while phloem translocates food in both directions using energy.

Excretion in humans

Removal of nitrogenous wastes by the kidneys, where each nephron filters blood and selectively reabsorbs useful substances.

Nephron

The functional unit of the kidney, in which filtration at the glomerulus is followed by selective reabsorption of glucose, salts and water.