- 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. - 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 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 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 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 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 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 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 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 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 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 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 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 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 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 controls the amount of light entering?
(A) Cornea
(B) Iris
(C) Lens
(D) Retina
Answer: (B)
Explanation: The iris adjusts the pupil size to control light entry. - 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 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 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. - Which mineral is essential for the synthesis 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 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 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 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 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 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 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 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.