Class 10 NCERT General Science MCQs-Chapter 5-Life Processes
NCERT MCQs of Class 10 General Science, Chapter no 5 (Life Processes)
1) Which of the following is not a life process?
(a) Respiration
(b) Nutrition
(c) Excretion
(d) Growth of crystals
Answer: (d) Growth of crystals
Explanation: Life processes are activities performed by living organisms to sustain life, and growth of crystals is a physical process, not a biological one.
2) What is the primary source of energy for living organisms?
(a) Carbohydrates
(b) Sunlight
(c) Vitamins
(d) Proteins
Answer: (b) Sunlight
Explanation: Sunlight is the primary energy source for life on Earth, as it powers photosynthesis in plants.
3) In which part of the plant does photosynthesis mainly occur?
(a) Roots
(b) Stem
(c) Leaves
(d) Flowers
Answer: (c) Leaves
Explanation: Leaves contain chlorophyll, which captures sunlight to perform photosynthesis.
4) What is the end product of photosynthesis?
(a) Oxygen and glucose
(b) Carbon dioxide and water
(c) Chlorophyll and oxygen
(d) Glucose and carbon dioxide
Answer: (a) Oxygen and glucose
Explanation: Photosynthesis produces glucose (energy source) and releases oxygen as a byproduct.
5) Which of the following is required for photosynthesis?
(a) Nitrogen
(b) Oxygen
(c) Carbon dioxide
(d) Sulfur dioxide
Answer: (c) Carbon dioxide
Explanation: Carbon dioxide is one of the raw materials used in photosynthesis to produce glucose.
6) Which enzyme is responsible for breaking down starch into simple sugars?
(a) Amylase
(b) Lipase
(c) Protease
(d) Cellulase
Answer: (a) Amylase
Explanation: Amylase is an enzyme that breaks down starch into maltose and glucose during digestion.
7) Which of the following organisms can perform chemosynthesis?
(a) Algae
(b) Fungi
(c) Chemotrophic bacteria
(d) Viruses
Answer: (c) Chemotrophic bacteria
Explanation: Chemotrophic bacteria obtain energy by oxidizing inorganic substances, a process known as chemosynthesis.
8) What is the role of stomata in plants?
(a) Transport of nutrients
(b) Exchange of gases
(c) Absorption of water
(d) Photosynthesis
Answer: (b) Exchange of gases
Explanation: Stomata are small openings on leaves that allow the exchange of oxygen and carbon dioxide.
9) Which molecule acts as an energy currency in cells?
(a) DNA
(b) RNA
(c) ATP
(d) NADPH
Answer: (c) ATP
Explanation: Adenosine Triphosphate (ATP) stores and provides energy for various cellular processes.
10) What is the function of hemoglobin in the human body?
(a) Digestion of food
(b) Transport of oxygen
(c) Breakdown of glucose
(d) Production of enzymes
Answer: (b) Transport of oxygen
Explanation: Hemoglobin in red blood cells binds to oxygen and transports it to tissues.
11) Which part of the human digestive system absorbs most of the nutrients?
(a) Stomach
(b) Small intestine
(c) Large intestine
(d) Liver
Answer: (b) Small intestine
Explanation: The small intestine contains villi that increase surface area for the absorption of nutrients.
12) What is the end product of protein digestion?
(a) Glucose
(b) Amino acids
(c) Fatty acids
(d) Glycerol
Answer: (b) Amino acids
Explanation: Proteins are broken down into amino acids, which are absorbed into the bloodstream.
13) Which organ is responsible for filtering blood and forming urine?
(a) Liver
(b) Lungs
(c) Kidneys
(d) Heart
Answer: (c) Kidneys
Explanation: The kidneys filter waste products from the blood and excrete them as urine.
14) What is the primary waste product excreted by plants?
(a) Carbon dioxide
(b) Oxygen
(c) Water
(d) All of the above
Answer: (d) All of the above
Explanation: Plants release carbon dioxide during respiration, oxygen during photosynthesis, and water vapor through transpiration.
15) What is the main purpose of the circulatory system?
(a) Production of energy
(b) Transport of nutrients, oxygen, and waste products
(c) Control of body temperature
(d) Digestion of food
Answer: (b) Transport of nutrients, oxygen, and waste products
Explanation: The circulatory system distributes oxygen and nutrients to cells and removes waste products.
16) Which pigment is responsible for the green color in plants?
(a) Xanthophyll
(b) Carotene
(c) Chlorophyll
(d) Anthocyanin
Answer: (c) Chlorophyll
Explanation: Chlorophyll absorbs sunlight for photosynthesis and gives plants their green color.
17) What is the process of removing metabolic waste from the body called?
(a) Nutrition
(b) Excretion
(c) Respiration
(d) Transpiration
Answer: (b) Excretion
Explanation: Excretion involves the removal of metabolic wastes such as urea, carbon dioxide, and excess salts.
18) Which of the following is an autotrophic mode of nutrition?
(a) Parasitism
(b) Saprophytism
(c) Photosynthesis
(d) Symbiosis
Answer: (c) Photosynthesis
Explanation: Autotrophs like green plants synthesize their own food using sunlight, carbon dioxide, and water.
19) What is the main component of human blood?
(a) Platelets
(b) Red blood cells
(c) Plasma
(d) White blood cells
Answer: (c) Plasma
Explanation: Plasma, the liquid portion of blood, makes up about 55% of total blood volume and transports nutrients and hormones.
20) What happens to glucose in the absence of oxygen during respiration?
(a) Complete oxidation to carbon dioxide and water
(b) Conversion to lactic acid or alcohol
(c) Storage as glycogen
(d) Breakdown into amino acids
Answer: (b) Conversion to lactic acid or alcohol
Explanation: In anaerobic respiration, glucose is partially broken down into lactic acid in animals or alcohol in microorganisms.
21) Which structure in plants transports water and minerals from roots to other parts?
(a) Phloem
(b) Xylem
(c) Stomata
(d) Chloroplasts
Answer: (b) Xylem
Explanation: Xylem is responsible for transporting water and dissolved minerals from roots to leaves and other parts of the plant.
22) What is the primary function of the phloem in plants?
(a) Transport of water
(b) Transport of food
(c) Absorption of nutrients
(d) Gas exchange
Answer: (b) Transport of food
Explanation: Phloem transports the products of photosynthesis (like glucose) from leaves to other parts of the plant.
23) Which of the following processes is responsible for water loss in plants?
(a) Transpiration
(b) Photosynthesis
(c) Absorption
(d) Respiration
Answer: (a) Transpiration
Explanation: Transpiration is the process where water is lost as vapor through stomata in leaves.
24) What is the main component of bile?
(a) Hydrochloric acid
(b) Bile salts
(c) Lipase
(d) Amylase
Answer: (b) Bile salts
Explanation: Bile contains bile salts, which help emulsify fats for easier digestion by enzymes.
25) What is the role of villi in the small intestine?
(a) Secretion of enzymes
(b) Absorption of nutrients
(c) Breakdown of proteins
(d) Excretion of waste products
Answer: (b) Absorption of nutrients
Explanation: Villi are finger-like projections that increase the surface area for the efficient absorption of nutrients.
26) Which part of the human brain controls involuntary actions like breathing?
(a) Cerebrum
(b) Cerebellum
(c) Medulla oblongata
(d) Hypothalamus
Answer: (c) Medulla oblongata
Explanation: The medulla oblongata regulates involuntary functions like heartbeat, breathing, and digestion.
27) What is the byproduct of anaerobic respiration in muscle cells?
(a) Carbon dioxide
(b) Lactic acid
(c) Ethanol
(d) Water
Answer: (b) Lactic acid
Explanation: During anaerobic respiration, glucose is broken down into lactic acid, causing muscle fatigue.
28) What is the primary function of the alveoli in the lungs?
(a) Transport of oxygen
(b) Gas exchange between air and blood
(c) Breakdown of carbon dioxide
(d) Absorption of nutrients
Answer: (b) Gas exchange between air and blood
Explanation: Alveoli provide a large surface area for the exchange of oxygen and carbon dioxide with the blood.
29) What is the functional unit of the kidney?
(a) Neuron
(b) Alveolus
(c) Nephron
(d) Glomerulus
Answer: (c) Nephron
Explanation: The nephron is the structural and functional unit of the kidney that filters blood to form urine.
30) Which blood vessel carries oxygenated blood from the lungs to the heart?
(a) Pulmonary artery
(b) Pulmonary vein
(c) Aorta
(d) Vena cava
Answer: (b) Pulmonary vein
Explanation: The pulmonary vein carries oxygen-rich blood from the lungs to the left atrium of the heart.
31) Which nutrient is digested in the stomach?
(a) Carbohydrates
(b) Fats
(c) Proteins
(d) Vitamins
Answer: (c) Proteins
Explanation: Proteins are broken down into peptides in the stomach by pepsin, an enzyme activated by gastric acid.
32) Which substance is responsible for the yellowish color of urine?
(a) Urea
(b) Urochrome
(c) Creatinine
(d) Uric acid
Answer: (b) Urochrome
Explanation: Urochrome, a pigment formed by the breakdown of hemoglobin, gives urine its characteristic yellow color.
33) What is the primary role of platelets in blood?
(a) Oxygen transport
(b) Blood clotting
(c) Immunity
(d) Nutrient transport
Answer: (b) Blood clotting
Explanation: Platelets help form clots to prevent bleeding and aid in wound healing.
34) Which gas is released as a byproduct of cellular respiration?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Methane
Answer: (c) Carbon dioxide
Explanation: Cellular respiration breaks down glucose to produce energy, releasing carbon dioxide as a byproduct.
35) What is the storage form of glucose in animals?
(a) Cellulose
(b) Glycogen
(c) Starch
(d) Lactic acid
Answer: (b) Glycogen
Explanation: Excess glucose is stored as glycogen in the liver and muscles for energy reserves in animals.
36) Which of the following organs performs detoxification in humans?
(a) Kidneys
(b) Liver
(c) Lungs
(d) Stomach
Answer: (b) Liver
Explanation: The liver detoxifies harmful substances, metabolizes drugs, and produces bile.
37) What is the main function of red blood cells (RBCs)?
(a) Immunity
(b) Transport of oxygen and carbon dioxide
(c) Blood clotting
(d) Hormone production
Answer: (b) Transport of oxygen and carbon dioxide
Explanation: RBCs contain hemoglobin, which binds to oxygen and carbon dioxide for transport throughout the body.
38) In which process do root hairs absorb water from the soil?
(a) Osmosis
(b) Diffusion
(c) Active transport
(d) Translocation
Answer: (a) Osmosis
Explanation: Root hairs absorb water from the soil through osmosis, where water moves from high to low water potential.
39) What is the energy currency of the cell?
(a) DNA
(b) ATP
(c) RNA
(d) Glucose
Answer: (b) ATP
Explanation: Adenosine Triphosphate (ATP) stores energy used for various cellular activities.
40) Which hormone regulates the reabsorption of water in the kidneys?
(a) Insulin
(b) Adrenaline
(c) Vasopressin
(d) Glucagon
Answer: (c) Vasopressin
Explanation: Vasopressin, also known as antidiuretic hormone (ADH), controls water reabsorption in the kidney tubules.
41) Which component of the blood helps in fighting infections?
(a) Platelets
(b) Red blood cells
(c) White blood cells
(d) Plasma
Answer: (c) White blood cells
Explanation: White blood cells (WBCs) are part of the immune system and help protect the body from infections.
42) What is the major site of photosynthesis in plants?
(a) Xylem
(b) Phloem
(c) Chloroplasts
(d) Mitochondria
Answer: (c) Chloroplasts
Explanation: Chloroplasts in the leaf cells contain chlorophyll, which captures sunlight for photosynthesis.
43) What is the role of the epiglottis in the human body?
(a) Prevents food from entering the windpipe
(b) Assists in swallowing
(c) Aids in digestion
(d) Helps in respiration
Answer: (a) Prevents food from entering the windpipe
Explanation: The epiglottis is a flap-like structure that covers the trachea during swallowing, preventing food from entering the airway.
44) Which part of the plant is mainly responsible for transpiration?
(a) Stomata
(b) Xylem
(c) Roots
(d) Flowers
Answer: (a) Stomata
Explanation: Stomata are tiny pores on the surface of leaves that release water vapor during transpiration.
45) What is the process of converting glucose into pyruvate called?
(a) Krebs cycle
(b) Glycolysis
(c) Electron transport chain
(d) Fermentation
Answer: (b) Glycolysis
Explanation: Glycolysis is the first step in cellular respiration where glucose is broken down into pyruvate, releasing energy.
46) Which substance is responsible for emulsifying fats in the digestive system?
(a) Bile
(b) Amylase
(c) Lipase
(d) Pepsin
Answer: (a) Bile
Explanation: Bile, produced by the liver, breaks down large fat molecules into smaller droplets for digestion.
47) What is the primary function of the large intestine?
(a) Digestion of carbohydrates
(b) Absorption of water and salts
(c) Secretion of digestive enzymes
(d) Excretion of bile
Answer: (b) Absorption of water and salts
Explanation: The large intestine absorbs water and salts from the undigested food and forms feces.
48) What is the primary function of guard cells in plants?
(a) Photosynthesis
(b) Closing and opening of stomata
(c) Transport of food
(d) Absorption of water
Answer: (b) Closing and opening of stomata
Explanation: Guard cells regulate the opening and closing of stomata to control gas exchange and water loss.
49) Which part of the heart pumps oxygenated blood to the body?
(a) Left atrium
(b) Left ventricle
(c) Right atrium
(d) Right ventricle
Answer: (b) Left ventricle
Explanation: The left ventricle pumps oxygenated blood into the aorta, which distributes it throughout the body.
50) Which enzyme breaks down fats into fatty acids and glycerol?
(a) Amylase
(b) Lipase
(c) Protease
(d) Trypsin
Answer: (b) Lipase
Explanation: Lipase breaks down fats into fatty acids and glycerol for absorption.
51) Which process in plants helps in cooling and maintaining temperature?
(a) Photosynthesis
(b) Transpiration
(c) Respiration
(d) Absorption
Answer: (b) Transpiration
Explanation: Transpiration cools plants by releasing water vapor and maintaining their temperature.
52) Which organ stores bile in the human body?
(a) Liver
(b) Gallbladder
(c) Stomach
(d) Pancreas
Answer: (b) Gallbladder
Explanation: Bile is stored in the gallbladder and released into the small intestine to aid in fat digestion.
53) What is the main function of the diaphragm in respiration?
(a) Excretes waste products
(b) Pushes food down the esophagus
(c) Controls the movement of air in and out of the lungs
(d) Filters air before entering the lungs
Answer: (c) Controls the movement of air in and out of the lungs
Explanation: The diaphragm contracts and flattens to allow air to enter the lungs and relaxes to expel it.
54) What is the source of energy during prolonged physical activity when oxygen is insufficient?
(a) Proteins
(b) Glycogen
(c) Fats
(d) Lactic acid fermentation
Answer: (d) Lactic acid fermentation
Explanation: In the absence of oxygen, muscles use anaerobic respiration, producing energy and lactic acid.
55) Which gas diffuses out of the blood in the alveoli?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Methane
Answer: (b) Carbon dioxide
Explanation: Carbon dioxide diffuses from the blood into the alveoli to be exhaled during respiration.
56) Which blood vessel carries deoxygenated blood from the body to the heart?
(a) Pulmonary vein
(b) Pulmonary artery
(c) Vena cava
(d) Aorta
Answer: (c) Vena cava
Explanation: The vena cava carries deoxygenated blood from the body to the right atrium of the heart.
57) What is the process by which plants lose water vapor through leaves?
(a) Respiration
(b) Photosynthesis
(c) Transpiration
(d) Osmosis
Answer: (c) Transpiration
Explanation: Transpiration is the evaporation of water from leaves through stomata.
58) What are the raw materials required for photosynthesis?
(a) Oxygen and water
(b) Carbon dioxide and water
(c) Glucose and oxygen
(d) Nitrogen and sunlight
Answer: (b) Carbon dioxide and water
Explanation: Carbon dioxide, water, and sunlight are required for photosynthesis.
59) Which organ helps in detoxifying harmful substances in the body?
(a) Kidneys
(b) Liver
(c) Heart
(d) Lungs
Answer: (b) Liver
Explanation: The liver detoxifies harmful substances, including drugs and alcohol, and converts them into harmless forms.
60) Which of the following processes occurs in the mitochondria of cells?
(a) Glycolysis
(b) Photosynthesis
(c) Krebs cycle
(d) Fermentation
Answer: (c) Krebs cycle
Explanation: The Krebs cycle, part of cellular respiration, occurs in the mitochondria to generate energy in the form of ATP.
61) Which enzyme in saliva helps in the digestion of starch?
(a) Pepsin
(b) Amylase
(c) Lipase
(d) Protease
Answer: (b) Amylase
Explanation: Salivary amylase breaks down starch into maltose, initiating carbohydrate digestion in the mouth.
62) What is the primary function of the stomach in digestion?
(a) Absorption of nutrients
(b) Digestion of carbohydrates
(c) Digestion of proteins
(d) Breakdown of fats
Answer: (c) Digestion of proteins
Explanation: The stomach secretes gastric juices containing pepsin, which breaks down proteins into peptides.
63) Which acid is secreted in the stomach to aid digestion?
(a) Hydrochloric acid
(b) Sulfuric acid
(c) Acetic acid
(d) Nitric acid
Answer: (a) Hydrochloric acid
Explanation: Hydrochloric acid (HCl) creates an acidic environment in the stomach, activating pepsin and killing bacteria.
64) Which part of the digestive system is responsible for maximum absorption of nutrients?
(a) Stomach
(b) Large intestine
(c) Small intestine
(d) Esophagus
Answer: (c) Small intestine
Explanation: The small intestine, lined with villi, absorbs most of the nutrients from digested food.
65) Which organ produces bile?
(a) Stomach
(b) Pancreas
(c) Liver
(d) Gallbladder
Answer: (c) Liver
Explanation: The liver produces bile, which emulsifies fats, making them easier to digest.
66) What is the role of the gallbladder in digestion?
(a) Produces enzymes
(b) Stores and concentrates bile
(c) Absorbs nutrients
(d) Breaks down proteins
Answer: (b) Stores and concentrates bile
Explanation: The gallbladder stores bile and releases it into the small intestine when needed.
67) Which digestive juice contains enzymes for digesting carbohydrates, proteins, and fats?
(a) Bile
(b) Pancreatic juice
(c) Gastric juice
(d) Intestinal juice
Answer: (b) Pancreatic juice
Explanation: Pancreatic juice contains amylase (for carbohydrates), lipase (for fats), and trypsin (for proteins).
68) Which part of the human body absorbs water from undigested food?
(a) Small intestine
(b) Large intestine
(c) Stomach
(d) Rectum
Answer: (b) Large intestine
Explanation: The large intestine absorbs water and salts from undigested food and forms feces.
69) What is the function of the epiglottis during swallowing?
(a) Prevents food from entering the windpipe
(b) Secretes enzymes
(c) Aids in digestion of proteins
(d) Pushes food down the esophagus
Answer: (a) Prevents food from entering the windpipe
Explanation: The epiglottis closes the trachea during swallowing, ensuring food moves into the esophagus.
70) What is the role of the tongue in digestion?
(a) Produces enzymes
(b) Absorbs nutrients
(c) Helps in mixing food with saliva and swallowing
(d) Breaks down proteins
Answer: (c) Helps in mixing food with saliva and swallowing
Explanation: The tongue mixes food with saliva, aids in chewing, and pushes food towards the esophagus.
71) What is the function of the small intestine's villi?
(a) Secretion of bile
(b) Breakdown of fats
(c) Increase surface area for nutrient absorption
(d) Produce digestive enzymes
Answer: (c) Increase surface area for nutrient absorption
Explanation: Villi are small finger-like projections that maximize nutrient absorption in the small intestine.
72) What is the end product of fat digestion?
(a) Glucose and amino acids
(b) Fatty acids and glycerol
(c) Starch and maltose
(d) Peptides and amino acids
Answer: (b) Fatty acids and glycerol
Explanation: Fats are broken down into fatty acids and glycerol by lipase for absorption.
73) Which enzyme is secreted by the pancreas to digest proteins?
(a) Amylase
(b) Lipase
(c) Trypsin
(d) Pepsin
Answer: (c) Trypsin
Explanation: Trypsin, secreted by the pancreas, helps digest proteins in the small intestine.
74) What is the function of the esophagus in digestion?
(a) Breakdown of carbohydrates
(b) Absorption of nutrients
(c) Transport of food from mouth to stomach
(d) Secretion of digestive juices
Answer: (c) Transport of food from mouth to stomach
Explanation: The esophagus uses peristaltic movements to push food into the stomach.
75) What is peristalsis?
(a) Mixing of food with enzymes
(b) Rhythmic contraction of muscles to move food through the digestive tract
(c) Breaking down food into smaller pieces
(d) Absorption of nutrients
Answer: (b) Rhythmic contraction of muscles to move food through the digestive tract
Explanation: Peristalsis refers to the wave-like muscular contractions that propel food along the digestive system.
76) Which of the following organisms show holozoic nutrition?
(a) Fungi
(b) Amoeba
(c) Yeast
(d) Algae
Answer: (b) Amoeba
Explanation: Holozoic nutrition involves ingestion, digestion, absorption, and assimilation, as seen in Amoeba.
77) What is the primary site of gas exchange in humans?
(a) Trachea
(b) Bronchi
(c) Alveoli
(d) Pharynx
Answer: (c) Alveoli
Explanation: Alveoli are microscopic sacs in the lungs where oxygen and carbon dioxide are exchanged with blood.
78) Which process moves food down the esophagus?
(a) Diffusion
(b) Peristalsis
(c) Transpiration
(d) Osmosis
Answer: (b) Peristalsis
Explanation: Peristalsis is the wave-like muscular movement that pushes food through the esophagus.
79) In which organ does the majority of water absorption occur in the human body?
(a) Stomach
(b) Large intestine
(c) Small intestine
(d) Esophagus
Answer: (b) Large intestine
Explanation: The large intestine absorbs most of the water from undigested food.
80) Which blood component carries nutrients, hormones, and waste products?
(a) Red blood cells
(b) Plasma
(c) White blood cells
(d) Platelets
Answer: (b) Plasma
Explanation: Plasma, the liquid portion of blood, transports nutrients, hormones, and waste products.
81) What is the major function of the pulmonary artery?
(a) Carry oxygen-rich blood to the body
(b) Carry deoxygenated blood to the lungs
(c) Carry oxygenated blood to the lungs
(d) Carry deoxygenated blood to the heart
Answer: (b) Carry deoxygenated blood to the lungs
Explanation: The pulmonary artery transports deoxygenated blood from the heart to the lungs for oxygenation.
82) Which molecule stores energy for immediate use in cells?
(a) ATP
(b) DNA
(c) RNA
(d) Glucose
Answer: (a) ATP
Explanation: Adenosine Triphosphate (ATP) is the energy currency of cells.
83) Which plant tissue is responsible for transporting food?
(a) Xylem
(b) Phloem
(c) Epidermis
(d) Cortex
Answer: (b) Phloem
Explanation: Phloem transports food produced in leaves to other parts of the plant.
84) Which type of respiration occurs in yeast cells in the absence of oxygen?
(a) Aerobic respiration
(b) Anaerobic respiration
(c) Chemosynthesis
(d) Photophosphorylation
Answer: (b) Anaerobic respiration
Explanation: Yeast performs anaerobic respiration, converting glucose into alcohol and carbon dioxide.
85) Which structure in plants prevents excessive water loss?
(a) Xylem
(b) Phloem
(c) Guard cells
(d) Stomata
Answer: (c) Guard cells
Explanation: Guard cells regulate the opening and closing of stomata, minimizing water loss.
86) What is the product of the anaerobic breakdown of glucose in animal muscle cells?
(a) Alcohol
(b) Lactic acid
(c) Carbon dioxide
(d) Glucose
Answer: (b) Lactic acid
Explanation: In the absence of oxygen, glucose is broken down into lactic acid in animal muscle cells.
87) What is the main function of the hepatic portal vein?
(a) Transport oxygenated blood to the liver
(b) Transport deoxygenated blood from the liver
(c) Transport nutrient-rich blood from the digestive system to the liver
(d) Transport carbon dioxide to the lungs
Answer: (c) Transport nutrient-rich blood from the digestive system to the liver
Explanation: The hepatic portal vein carries nutrients absorbed from the intestines to the liver for processing.
88) What is the function of stomata in plants?
(a) Absorb water
(b) Exchange gases
(c) Transport nutrients
(d) Store energy
Answer: (b) Exchange gases
Explanation: Stomata allow the exchange of oxygen, carbon dioxide, and water vapor.
89) What is the final product of protein digestion?
(a) Glucose
(b) Fatty acids
(c) Amino acids
(d) Starch
Answer: (c) Amino acids
Explanation: Proteins are broken down into amino acids, which are absorbed in the small intestine.
90) Which process in plants is responsible for the upward movement of water?
(a) Diffusion
(b) Osmosis
(c) Transpiration pull
(d) Photosynthesis
Answer: (c) Transpiration pull
Explanation: Transpiration creates a suction force that pulls water upward through the xylem.
91) Which gas is essential for aerobic respiration?
(a) Carbon dioxide
(b) Nitrogen
(c) Oxygen
(d) Methane
Answer: (c) Oxygen
Explanation: Oxygen is required for the complete breakdown of glucose during aerobic respiration.
92) What is the function of the pancreas in digestion?
(a) Absorb nutrients
(b) Produce bile
(c) Secrete enzymes like amylase, lipase, and trypsin
(d) Store glucose
Answer: (c) Secrete enzymes like amylase, lipase, and trypsin
Explanation: The pancreas produces digestive enzymes to break down carbohydrates, fats, and proteins.
93) What is the role of hemoglobin in respiration?
(a) Break down glucose
(b) Transport oxygen
(c) Regulate blood pressure
(d) Absorb nutrients
Answer: (b) Transport oxygen
Explanation: Hemoglobin binds with oxygen in the lungs and transports it to tissues.
94) Which organ is responsible for filtering urea from the blood?
(a) Liver
(b) Kidneys
(c) Lungs
(d) Stomach
Answer: (b) Kidneys
Explanation: The kidneys filter urea and other waste products from the blood to form urine.
95) What is the primary source of energy for living organisms?
(a) Proteins
(b) Fats
(c) Carbohydrates
(d) Vitamins
Answer: (c) Carbohydrates
Explanation: Carbohydrates are the primary energy source for organisms, broken down into glucose for cellular respiration.
96) Which process in plants releases oxygen into the atmosphere?
(a) Transpiration
(b) Respiration
(c) Photosynthesis
(d) Diffusion
Answer: (c) Photosynthesis
Explanation: During photosynthesis, plants release oxygen as a byproduct of splitting water molecules.
97) What is the function of nephrons in the kidney?
(a) Reabsorb water and nutrients
(b) Transport blood
(c) Release hormones
(d) Store urine
Answer: (a) Reabsorb water and nutrients
Explanation: Nephrons filter blood, reabsorb essential substances, and excrete waste as urine.
98) Which of the following is an example of autotrophic nutrition?
(a) Parasitism
(b) Photosynthesis
(c) Saprophytism
(d) Symbiosis
Answer: (b) Photosynthesis
Explanation: Autotrophs, like plants, prepare their own food using sunlight, carbon dioxide, and water.
99) Which digestive enzyme is produced in the stomach?
(a) Amylase
(b) Pepsin
(c) Lipase
(d) Trypsin
Answer: (b) Pepsin
Explanation: Pepsin is secreted in the stomach and breaks down proteins into peptides.
100) What is the structural and functional unit of the lungs?
(a) Bronchioles
(b) Alveoli
(c) Trachea
(d) Larynx
Answer: (b) Alveoli
Explanation: Alveoli are tiny air sacs where gas exchange occurs between blood and air.
MCQs from the Exercise part of the chapter
1) The kidneys in human beings are a part of the system for
(a) Nutrition
(b) Respiration
(c) Excretion
(d) Transportation
Answer: (c) Excretion
Explanation: The kidneys filter blood and remove nitrogenous waste products like urea, making them a part of the excretory system.
2) 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
Explanation: Xylem conducts water and minerals from the roots to the rest of the plant.
3) 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
Explanation: Autotrophic nutrition requires carbon dioxide, water, chlorophyll, and sunlight to synthesize food through photosynthesis.
4) 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
Explanation: Mitochondria are the powerhouse of the cell where aerobic respiration occurs, breaking down pyruvate into carbon dioxide, water, and ATP.
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