- Which organelle is known as the “powerhouse” of the cell?
(A) Nucleus
(B) Ribosome
(C) Mitochondria
(D) Lysosome
Answer: (C)
Explanation: Mitochondria generate ATP through cellular respiration, supplying energy for all cellular activities. They are called the “powerhouse” because they convert energy from nutrients into a usable form. - Which vitamin is essential for blood clotting?
(A) Vitamin A
(B) Vitamin C
(C) Vitamin D
(D) Vitamin K
Answer: (D)
Explanation: Vitamin K is necessary for the synthesis of clotting factors in the liver. Its deficiency leads to excessive bleeding and poor wound healing. - Which process describes the movement of water from an area of low solute concentration to high solute concentration through a membrane?
(A) Diffusion
(B) Osmosis
(C) Active transport
(D) Endocytosis
Answer: (B)
Explanation: Osmosis is the passive movement of water across a semi-permeable membrane toward a region of higher solute concentration, helping maintain cell turgor and fluid balance. - Which hormone is responsible for regulating blood sugar by increasing glucose uptake by cells?
(A) Glucagon
(B) Insulin
(C) Adrenaline
(D) Thyroxine
Answer: (B)
Explanation: Insulin, secreted by the pancreas, lowers blood sugar by promoting glucose uptake by cells and storage as glycogen. - Which mineral is essential for the formation of thyroid hormones?
(A) Calcium
(B) Iron
(C) Iodine
(D) Magnesium
Answer: (C)
Explanation: Iodine is a key component of thyroid hormones (T3 and T4), necessary for regulating metabolism. Its deficiency can cause goiter. - Which enzyme breaks down proteins in the small intestine?
(A) Amylase
(B) Lipase
(C) Trypsin
(D) Maltase
Answer: (C)
Explanation: Trypsin, produced by the pancreas, digests proteins into smaller peptides in the small intestine. - Which vitamin deficiency causes night blindness?
(A) Vitamin A
(B) Vitamin B1
(C) Vitamin C
(D) Vitamin D
Answer: (A)
Explanation: Vitamin A deficiency impairs the production of rhodopsin in the retina, leading to night blindness. - Which structure in the human ear maintains balance?
(A) Cochlea
(B) Semicircular canals
(C) Ossicles
(D) Eardrum
Answer: (B)
Explanation: The semicircular canals in the inner ear detect head movements and help maintain the body’s sense of balance. - Which hormone is responsible for stimulating milk production after childbirth?
(A) Prolactin
(B) Oxytocin
(C) Estrogen
(D) Progesterone
Answer: (A)
Explanation: Prolactin, secreted by the pituitary gland, stimulates the mammary glands to produce milk after childbirth. - Which part of the plant is responsible for absorbing water and minerals from the soil?
(A) Leaf
(B) Stem
(C) Root
(D) Flower
Answer: (C)
Explanation: Roots anchor the plant and absorb water and minerals from the soil, supplying them to the rest of the plant. - 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)
Explanation: The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. - Which hormone is responsible for stimulating uterine contractions during childbirth?
(A) Estrogen
(B) Progesterone
(C) Prolactin
(D) Oxytocin
Answer: (D)
Explanation: Oxytocin, released by the pituitary gland, stimulates powerful uterine contractions during labor and also aids milk ejection during breastfeeding. - Which mineral is essential for muscle contraction and nerve transmission?
(A) Iron
(B) Calcium
(C) Magnesium
(D) Zinc
Answer: (B)
Explanation: Calcium ions are crucial for muscle contraction, nerve impulse transmission, and blood clotting. - Which enzyme breaks down starch into maltose?
(A) Amylase
(B) Lipase
(C) Pepsin
(D) Trypsin
Answer: (A)
Explanation: Amylase, present in saliva and pancreatic juice, breaks down starch into maltose, a disaccharide. - Which organ in the human body is responsible for detoxifying drugs and alcohol?
(A) Kidney
(B) Liver
(C) Pancreas
(D) Spleen
Answer: (B)
Explanation: The liver metabolizes and detoxifies drugs, alcohol, and other harmful substances, making them less toxic for excretion. - Which structure in the human eye changes shape to focus light?
(A) Cornea
(B) Lens
(C) Iris
(D) Retina
Answer: (B)
Explanation: The lens is flexible and changes shape (accommodation) to focus light onto the retina for clear vision. - Which hormone stimulates the release of glucose from the liver into the blood?
(A) Insulin
(B) Glucagon
(C) Thyroxine
(D) Cortisol
Answer: (B)
Explanation: Glucagon, produced by the pancreas, signals the liver to convert stored glycogen into glucose and release it into the blood. - Which organ in the human body stores and concentrates urine before excretion?
(A) Kidney
(B) Bladder
(C) Ureter
(D) Urethra
Answer: (B)
Explanation: The bladder stores urine produced by the kidneys until it is excreted from the body. - Which vitamin deficiency causes beriberi?
(A) Vitamin B1
(B) Vitamin B2
(C) Vitamin B3
(D) Vitamin B12
Answer: (A)
Explanation: Beriberi is caused by a deficiency of thiamine (vitamin B1), affecting the nervous and cardiovascular systems. - Which structure in the human brain controls voluntary muscle movements?
(A) Medulla oblongata
(B) Cerebellum
(C) Cerebrum
(D) Hypothalamus
Answer: (C)
Explanation: The cerebrum is responsible for voluntary muscle movements, reasoning, memory, and sensory perception. - Which vitamin is essential for healthy skin and vision?
(A) Vitamin A
(B) Vitamin C
(C) Vitamin D
(D) Vitamin K
Answer: (A)
Explanation: Vitamin A is necessary for the maintenance of healthy skin, vision, and immune function. - Which hormone regulates the basal metabolic rate in humans?
(A) Insulin
(B) Thyroxine
(C) Adrenaline
(D) Progesterone
Answer: (B)
Explanation: Thyroxine, produced by the thyroid gland, increases the basal metabolic rate, affecting how quickly the body uses energy. - Which organ in the human body filters old red blood cells from the blood?
(A) Liver
(B) Spleen
(C) Kidney
(D) Pancreas
Answer: (B)
Explanation: The spleen filters and removes old or damaged red blood cells from circulation and helps fight infection. - Which process describes the transfer of pollen from anther to stigma?
(A) Fertilization
(B) Germination
(C) Pollination
(D) Seed dispersal
Answer: (C)
Explanation: Pollination is the transfer of pollen from the male anther to the female stigma, enabling fertilization in plants. - Which hormone is responsible for the development of secondary sexual characteristics in males?
(A) Estrogen
(B) Testosterone
(C) Progesterone
(D) Insulin
Answer: (B)
Explanation: Testosterone, produced by the testes, promotes the development of male secondary sexual characteristics such as facial hair and deep voice. - Which mineral is essential for the formation of hemoglobin?
(A) Calcium
(B) Iron
(C) Potassium
(D) Magnesium
Answer: (B)
Explanation: Iron is a key component of hemoglobin, the protein in red blood cells that binds and transports oxygen. - Which enzyme breaks down proteins in the stomach?
(A) Amylase
(B) Lipase
(C) Pepsin
(D) Maltase
Answer: (C)
Explanation: Pepsin is a protease enzyme secreted by the stomach that digests proteins into smaller peptides. - Which organ in the human body stores bile?
(A) Liver
(B) Pancreas
(C) Gallbladder
(D) Stomach
Answer: (C)
Explanation: The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion. - Which process produces ATP in the absence of oxygen?
(A) Aerobic respiration
(B) Anaerobic respiration
(C) Photosynthesis
(D) Chemosynthesis
Answer: (B)
Explanation: Anaerobic respiration (fermentation) produces ATP without oxygen, but yields less energy than aerobic respiration. - Which part of the human blood is responsible for clotting?
(A) Red blood cells
(B) White blood cells
(C) Platelets
(D) Plasma
Answer: (C)
Explanation: Platelets are cell fragments that help form clots to stop bleeding at injury sites. - Which vitamin is essential for the absorption of calcium from the intestine?
(A) Vitamin A
(B) Vitamin B12
(C) Vitamin C
(D) Vitamin D
Answer: (D)
Explanation: Vitamin D promotes the absorption of calcium from the intestine, which is vital for healthy bones and teeth. - Which hormone is responsible for stimulating milk ejection during breastfeeding?
(A) Oxytocin
(B) Prolactin
(C) Estrogen
(D) Progesterone
Answer: (A)
Explanation: Oxytocin causes the muscles around the mammary glands to contract, ejecting milk during breastfeeding. - Which mineral is essential for blood clotting?
(A) Iron
(B) Calcium
(C) Sodium
(D) Potassium
Answer: (B)
Explanation: Calcium is necessary for the activation of clotting factors and proper blood coagulation. - Which process describes the movement of food from the mouth to the stomach?
(A) Digestion
(B) Absorption
(C) Peristalsis
(D) Assimilation
Answer: (C)
Explanation: Peristalsis is the rhythmic contraction of muscles in the esophagus that pushes food toward the stomach. - Which hormone is responsible for the “fight or flight” response?
(A) Insulin
(B) Adrenaline
(C) Thyroxine
(D) Progesterone
Answer: (B)
Explanation: Adrenaline, secreted by the adrenal medulla, prepares the body to respond to stress by increasing heart rate, blood pressure, and energy availability. - Which structure in the human brain regulates body temperature?
(A) Cerebellum
(B) Medulla oblongata
(C) Hypothalamus
(D) Cerebrum
Answer: (C)
Explanation: The hypothalamus acts as the body’s thermostat, regulating temperature, hunger, thirst, and other autonomic functions. - Which vitamin deficiency causes scurvy?
(A) Vitamin A
(B) Vitamin B12
(C) Vitamin C
(D) Vitamin D
Answer: (C)
Explanation: Scurvy is caused by a deficiency of vitamin C, leading to bleeding gums, weakness, and poor wound healing. - Which part of the plant is responsible for photosynthesis?
(A) Root
(B) Stem
(C) Leaf
(D) Flower
Answer: (C)
Explanation: Leaves contain chloroplasts, where photosynthesis takes place, converting sunlight into chemical energy. - Which hormone stimulates the production of red blood cells?
(A) Insulin
(B) Erythropoietin
(C) Glucagon
(D) Thyroxine
Answer: (B)
Explanation: Erythropoietin, produced by the kidneys, stimulates the bone marrow to produce more red blood cells in response to low oxygen levels. - Which enzyme breaks down fats in the digestive system?
(A) Amylase
(B) Lipase
(C) Pepsin
(D) Maltase
Answer: (B)
Explanation: Lipase, produced by the pancreas, breaks down dietary fats into fatty acids and glycerol in the small intestine. - Which part of the human skeleton protects the spinal cord?
(A) Skull
(B) Rib cage
(C) Vertebral column
(D) Pelvis
Answer: (C)
Explanation: The vertebral column (spine) surrounds and protects the spinal cord from injury. - Which vitamin is necessary for the synthesis of visual pigments in the retina?
(A) Vitamin A
(B) Vitamin B6
(C) Vitamin C
(D) Vitamin D
Answer: (A)
Explanation: Vitamin A is required for the production of rhodopsin, a pigment in the retina essential for vision in low light. - Which hormone regulates water reabsorption in kidneys?
(A) Insulin
(B) Antidiuretic hormone
(C) Cortisol
(D) Thyroxine
Answer: (B)
Explanation: Antidiuretic hormone (ADH), secreted by the pituitary, promotes water reabsorption in kidneys to maintain fluid balance. - Which blood vessel carries deoxygenated blood from the body to the heart?
(A) Pulmonary vein
(B) Aorta
(C) Vena cava
(D) Pulmonary artery
Answer: (C)
Explanation: The vena cava (superior and inferior) carries deoxygenated blood from the body back to the right atrium of the heart. - Which hormone is responsible for stimulating milk production after childbirth?
(A) Prolactin
(B) Oxytocin
(C) Estrogen
(D) Progesterone
Answer: (A)
Explanation: Prolactin, secreted by the pituitary gland, stimulates the mammary glands to produce milk after childbirth. - Which mineral is essential for the formation of thyroid hormones?
(A) Calcium
(B) Iron
(C) Iodine
(D) Magnesium
Answer: (C)
Explanation: Iodine is a key component of thyroid hormones (T3 and T4), necessary for regulating metabolism. - Which structure in the human ear converts sound vibrations into nerve impulses?
(A) Ossicles
(B) Cochlea
(C) Eardrum
(D) Semicircular canals
Answer: (B)
Explanation: The cochlea is a spiral-shaped organ that converts sound vibrations into electrical signals for the brain to interpret as sound. - Which vitamin is essential for blood clotting?
(A) Vitamin A
(B) Vitamin C
(C) Vitamin D
(D) Vitamin K
Answer: (D)
Explanation: Vitamin K is necessary for the synthesis of clotting factors in the liver. Its deficiency leads to excessive bleeding and poor wound healing. - Which process describes the movement of water from roots to leaves in plants?
(A) Transpiration
(B) Respiration
(C) Photosynthesis
(D) Translocation
Answer: (A)
Explanation: Transpiration is the evaporation of water from plant leaves, creating a pull that moves water upward from the roots through the xylem. - Which hormone is responsible for the development of secondary sexual characteristics in females?
(A) Testosterone
(B) Estrogen
(C) Progesterone
(D) Insulin
Answer: (B)
Explanation: Estrogen, produced by the ovaries, promotes the development of female secondary sexual characteristics such as breast development and wider hips.