Understanding the fundamental life processes is crucial for Class 10 Science students. These processes—nutrition, respiration, transportation, and excretion—are vital for the survival and functioning of living organisms. This article provides a comprehensive set of multiple-choice questions (MCQs) on life processes, complete with answers and detailed explanations to aid in your learning.
1. Nutrition
Q1: Which of the following is an example of autotrophic nutrition?
(a) Human digestion
(b) Photosynthesis in plants
(c) Fungi absorbing nutrients
(d) Amoeba engulfing food
Answer: (b) Photosynthesis in plants
Explanation: Autotrophic nutrition involves organisms synthesizing their own food from simple substances. Plants perform photosynthesis to produce glucose from carbon dioxide and water.
Q2: In humans, the digestion of proteins begins in the:
(a) Mouth
(b) Stomach
(c) Small intestine
(d) Large intestine
Answer: (b) Stomach
Explanation: Proteins are primarily digested in the stomach, where the enzyme pepsin breaks them down into peptides.
Q3: Which of the following is a heterotrophic mode of nutrition?
(a) Photosynthesis
(b) Chemosynthesis
(c) Saprotrophic nutrition
(d) Parasitic nutrition
Answer: (c) Saprotrophic nutrition
Explanation: Saprotrophic nutrition involves organisms obtaining nutrients by decomposing dead organic matter, such as fungi and bacteria.
Q4: The process by which green plants make their own food is called:
(a) Respiration
(b) Photosynthesis
(c) Transpiration
(d) Digestion
Answer: (b) Photosynthesis
Explanation: Photosynthesis is the process by which plants convert light energy into chemical energy, producing glucose and oxygen.
Q5: Which of the following is NOT a product of photosynthesis?
(a) Oxygen
(b) Glucose
(c) Carbon dioxide
(d) Water
Answer: (c) Carbon dioxide
Explanation: Photosynthesis produces glucose and oxygen, utilizing carbon dioxide and water as raw materials.
2. Respiration
Q6: The process of releasing energy from food in the presence of oxygen is called:
(a) Fermentation
(b) Respiration
(c) Photosynthesis
(d) Transpiration
Answer: (b) Respiration
Explanation: Respiration is the process by which cells break down glucose and oxygen to release energy, carbon dioxide, and water.
Q7: Which of the following is the correct equation for aerobic respiration?
(a) Glucose + Oxygen → Carbon dioxide + Water + Energy
(b) Glucose → Lactic acid + Energy
(c) Glucose + Oxygen → Alcohol + Carbon dioxide + Energy
(d) Glucose → Alcohol + Energy
Answer: (a) Glucose + Oxygen → Carbon dioxide + Water + Energy
Explanation: Aerobic respiration involves the complete breakdown of glucose in the presence of oxygen, releasing energy, carbon dioxide, and water.
Q8: In which part of the human body does gas exchange occur?
(a) Stomach
(b) Small intestine
(c) Lungs
(d) Heart
Answer: (c) Lungs
Explanation: Gas exchange occurs in the alveoli of the lungs, where oxygen is absorbed into the blood, and carbon dioxide is expelled.
Q9: Which of the following is a byproduct of anaerobic respiration in muscles?
(a) Oxygen
(b) Lactic acid
(c) Carbon dioxide
(d) Glucose
Answer: (b) Lactic acid
Explanation: In the absence of sufficient oxygen, muscles perform anaerobic respiration, producing lactic acid and energy.
Q10: The energy currency of the cell is:
(a) Glucose
(b) ATP
(c) Oxygen
(d) Carbon dioxide
Answer: (b) ATP
Explanation: Adenosine triphosphate (ATP) is the primary energy carrier in cells, produced during respiration.
3. Transportation
Q11: In humans, the heart pumps blood into the:
(a) Lungs
(b) Stomach
(c) Kidneys
(d) Arteries
Answer: (d) Arteries
Explanation: The heart pumps oxygenated blood into the arteries, which then distribute it throughout the body.
Q12: Which of the following is responsible for transporting water in plants?
(a) Phloem
(b) Xylem
(c) Stomata
(d) Guard cells
Answer: (b) Xylem
Explanation: Xylem tissue transports water and minerals from the roots to other parts of the plant.
Q13: The main function of the phloem in plants is to:
(a) Transport water
(b) Transport food
(c) Transport minerals
(d) Transport oxygen
Answer: (b) Transport food
Explanation: Phloem transports the products of photosynthesis (mainly sugars) from leaves to other parts of the plant.
Q14: Which component of blood is responsible for clotting?
(a) Red blood cells
(b) White blood cells
(c) Platelets
(d) Plasma
Answer: (c) Platelets
Explanation: Platelets are cell fragments that play a crucial role in blood clotting to prevent excessive bleeding.
Q15: The liquid part of the blood is called:
(a) Plasma
(b) Serum
(c) Lymph
(d) Cytoplasm
Answer: (a) Plasma
Explanation: Plasma is the yellowish liquid component of blood that carries cells and proteins throughout the body.
4. Excretion
Q16: The functional unit of the kidney is the:
(a) Neuron
(b) Nephron
(c) Alveolus
(d) Villus
Answer: (b) Nephron
Explanation: Nephrons are the microscopic units in the kidneys that filter blood to form urine.
Q17: Which of the following is a nitrogenous waste excreted by humans?
(a) Urea
(b) Uric acid
(c) Ammonia
(d) All of the above
Answer: (a) Urea
Explanation: Humans primarily excrete urea, a less toxic nitrogenous waste, through urine.
Q18: In plants, the removal of excess water is known as:
(a) Transpiration
(b) Respiration
(c) Excretion
(d) Photosynthesis
Answer: (a) Transpiration
Explanation: Transpiration is the process by which plants lose water vapor through small openings called stomata.
Q19: Which of the following is NOT a method of excretion in plants?
(a) Guttation
(b) Transpiration
(c) Excretion through leaves
(d) Excretion through roots
Answer: (d)
Q20: Which is the correct sequence of blood flow through the human heart and lungs?
(a) Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body
(b) Right atrium → Left ventricle → Lungs → Left atrium → Right ventricle → Body
(c) Left atrium → Right atrium → Lungs → Left ventricle → Right ventricle → Body
(d) Right atrium → Lungs → Right ventricle → Body → Left ventricle → Left atrium
Answer: (a) Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body
Explanation: Blood enters the right atrium, is pumped into the right ventricle, then moves to the lungs to be oxygenated. From the lungs, it returns to the left atrium, passes into the left ventricle, and is pumped out to the body.
Q21: Which part of the plant is primarily responsible for the absorption of water?
(a) Leaves
(b) Stems
(c) Root hairs
(d) Flowers
Answer: (c) Root hairs
Explanation: Root hairs, which are extensions of root epidermal cells, increase the surface area for water and mineral absorption from the soil.
Q22: What is the main site of gaseous exchange in humans?
(a) Alveoli in the lungs
(b) Bronchi
(c) Trachea
(d) Diaphragm
Answer: (a) Alveoli in the lungs
Explanation: The alveoli are tiny sacs within the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out.
Q23: The main source of energy for all living organisms is:
(a) Protein
(b) Glucose
(c) Fat
(d) Minerals
Answer: (b) Glucose
Explanation: Glucose is the primary energy source that is broken down during respiration to produce ATP.
Q24: What is the term for the process by which plants lose water through their leaves?
(a) Evaporation
(b) Guttation
(c) Transpiration
(d) Photosynthesis
Answer: (c) Transpiration
Explanation: Transpiration is the loss of water vapor from the aerial parts of a plant, primarily through stomata on the leaves.
Q25: In which structure does filtration occur within the nephron?
(a) Loop of Henle
(b) Glomerulus
(c) Distal convoluted tubule
(d) Collecting duct
Answer: (b) Glomerulus
Explanation: The glomerulus is a network of capillaries within the Bowman’s capsule where blood filtration occurs.
Q26: Which of the following enzymes is involved in carbohydrate digestion in humans?
(a) Pepsin
(b) Amylase
(c) Lipase
(d) Trypsin
Answer: (b) Amylase
Explanation: Amylase is an enzyme found in saliva and pancreatic juice that breaks down starch into maltose and other simpler sugars.
Q27: What is the primary function of white blood cells?
(a) Transport oxygen
(b) Fight infections
(c) Clot blood
(d) Transport nutrients
Answer: (b) Fight infections
Explanation: White blood cells are a crucial part of the immune system and help defend the body against pathogens and foreign invaders.
Q28: Which organ is responsible for producing bile?
(a) Stomach
(b) Liver
(c) Pancreas
(d) Gallbladder
Answer: (b) Liver
Explanation: The liver produces bile, which is stored in the gallbladder and helps emulsify fats for digestion.
Q29: The process by which leaves of a plant remove oxygen produced during photosynthesis is called:
(a) Transpiration
(b) Respiration
(c) Gaseous exchange
(d) Photosynthesis
Answer: (c) Gaseous exchange
Explanation: Oxygen, a byproduct of photosynthesis, is released into the atmosphere through gaseous exchange via stomata.
Q30: What happens to the glucose formed during photosynthesis?
(a) It is immediately excreted
(b) It is stored as starch
(c) It is converted into oxygen
(d) It remains as glucose forever
Answer: (b) It is stored as starch
Explanation: Plants often store excess glucose produced during photosynthesis in the form of starch, which can be later converted back into glucose when needed.
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