- 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. This process is essential for nutrient transport and cooling of the plant. - Which organ in the human body is responsible for filtering blood and forming urine?
(A) Liver
(B) Kidney
(C) Spleen
(D) Pancreas
Answer: (B)
Explanation: The kidneys filter waste products and excess substances from the blood, forming urine for excretion. They also regulate fluid and electrolyte balance. - 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 throughout the body. - Which vitamin deficiency leads to rickets in children?
(A) Vitamin A
(B) Vitamin B12
(C) Vitamin C
(D) Vitamin D
Answer: (D)
Explanation: Vitamin D is essential for calcium absorption and bone health. Its deficiency causes rickets, resulting in soft and weak bones in children. - Which hormone regulates the sleep-wake cycle?
(A) Insulin
(B) Melatonin
(C) Adrenaline
(D) Thyroxine
Answer: (B)
Explanation: Melatonin, produced by the pineal gland, controls circadian rhythms and the sleep-wake cycle in humans. - Which structure in the human eye focuses light onto the retina?
(A) Cornea
(B) Lens
(C) Iris
(D) Sclera
Answer: (B)
Explanation: The lens is a transparent, flexible structure that adjusts its shape to focus light precisely onto the retina, enabling clear vision. - 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 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. - What is the main function of white blood cells?
(A) Oxygen transport
(B) Blood clotting
(C) Immune defense
(D) Hormone production
Answer: (C)
Explanation: White blood cells (leukocytes) protect the body against infections by identifying and destroying pathogens such as bacteria, viruses, and fungi. - Which process describes the breakdown of glucose to release energy in the absence of oxygen?
(A) Aerobic respiration
(B) Anaerobic respiration
(C) Photosynthesis
(D) Chemosynthesis
Answer: (B)
Explanation: Anaerobic respiration (fermentation) breaks down glucose without oxygen, producing less energy and byproducts like lactic acid or ethanol. - 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 necessary for the synthesis of thyroid hormones?
(A) Calcium
(B) Iron
(C) Iodine
(D) Magnesium
Answer: (C)
Explanation: Iodine is an essential component of thyroid hormones, which regulate metabolism. Its deficiency can cause goiter. - 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 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 process describes the movement of food through the digestive tract by muscular contractions?
(A) Digestion
(B) Absorption
(C) Peristalsis
(D) Assimilation
Answer: (C)
Explanation: Peristalsis is the wave-like contraction of smooth muscles that moves food along the digestive tract. - 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, preventing excessive bleeding. - 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 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 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 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 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 controls the reabsorption of water in the kidneys?
(A) Adrenaline
(B) Insulin
(C) Antidiuretic hormone
(D) Thyroxine
Answer: (C)
Explanation: Antidiuretic hormone (ADH), produced by the pituitary gland, increases water reabsorption in the kidneys to maintain fluid balance. - 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 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 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 part of the human skeleton protects the brain?
(A) Rib cage
(B) Pelvis
(C) Skull
(D) Vertebral column
Answer: (C)
Explanation: The skull is a bony structure that encases and protects the brain from injury. - 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 organ in the human body produces insulin?
(A) Liver
(B) Pancreas
(C) Kidney
(D) Spleen
Answer: (B)
Explanation: The pancreas contains beta cells in the islets of Langerhans that produce insulin, a hormone crucial for regulating blood glucose levels. - Which process describes the movement of molecules from high to low concentration?
(A) Active transport
(B) Diffusion
(C) Endocytosis
(D) Exocytosis
Answer: (B)
Explanation: Diffusion is the passive movement of molecules down their concentration gradient, requiring no energy. - 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 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 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 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 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 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 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 absorbs 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 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 process in plants produces glucose and oxygen using sunlight?
(A) Respiration
(B) Photosynthesis
(C) Fermentation
(D) Transpiration
Answer: (B)
Explanation: Photosynthesis is the process where plants use sunlight, carbon dioxide, and water to produce glucose and release oxygen. This occurs in the chloroplasts and is fundamental for plant energy and oxygen supply to the atmosphere.