- 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. - What is the main function of the human large intestine?
(A) Protein digestion
(B) Water absorption
(C) Nutrient absorption
(D) Enzyme production
Answer: (B)
Explanation: The large intestine absorbs water and electrolytes from indigestible food matter, forming solid feces. Most nutrient absorption occurs earlier in the digestive tract. - Which mineral is essential for thyroid hormone synthesis?
(A) Iron
(B) Iodine
(C) Calcium
(D) Sodium
Answer: (B)
Explanation: Iodine is required for the synthesis of thyroid hormones (T3 and T4), which regulate metabolism. Its deficiency can cause goiter. - Which organ in the human body produces bile?
(A) Pancreas
(B) Liver
(C) Gallbladder
(D) Spleen
Answer: (B)
Explanation: The liver produces bile, which is important for the emulsification and digestion of fats. The gallbladder stores bile, but does not produce it. - 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 symptoms like bleeding gums, weakness, and poor wound healing. - Which structure in plant cells stores water, nutrients, and waste products?
(A) Mitochondria
(B) Chloroplast
(C) Vacuole
(D) Ribosome
Answer: (C)
Explanation: The vacuole is a large, membrane-bound organelle in plant cells that stores water, nutrients, and waste, helping maintain cell turgor and structure. - What is the main function of hemoglobin in red blood cells?
(A) Digestion
(B) Oxygen transport
(C) Blood clotting
(D) Hormone production
Answer: (B)
Explanation: Hemoglobin binds oxygen in the lungs and transports it to tissues throughout the body. It also helps carry carbon dioxide back to the lungs for exhalation. - Which hormone regulates the sleep-wake cycle in humans?
(A) Insulin
(B) Melatonin
(C) Adrenaline
(D) Thyroxine
Answer: (B)
Explanation: Melatonin, produced by the pineal gland, regulates circadian rhythms and the sleep-wake cycle. - Which process describes the movement of water from roots to leaves in plants?
(A) Respiration
(B) Transpiration
(C) Photosynthesis
(D) Translocation
Answer: (B)
Explanation: Transpiration is the evaporation of water from plant leaves, creating a pull that moves water upward from the roots through the xylem. - 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 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 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 human brain controls voluntary muscle movements?
(A) Cerebrum
(B) Cerebellum
(C) Medulla oblongata
(D) Hypothalamus
Answer: (A)
Explanation: The cerebrum is responsible for voluntary muscle movements, reasoning, memory, and sensory perception. - 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 conversion of glucose into energy in the presence of oxygen?
(A) Anaerobic respiration
(B) Aerobic respiration
(C) Photosynthesis
(D) Fermentation
Answer: (B)
Explanation: Aerobic respiration uses oxygen to completely break down glucose, producing carbon dioxide, water, and a large amount of ATP. - 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 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 disease is caused by a deficiency of vitamin D in children?
(A) Rickets
(B) Scurvy
(C) Pellagra
(D) Beriberi
Answer: (A)
Explanation: Rickets is a bone disorder in children caused by vitamin D deficiency, resulting in soft, weak bones. - 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 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 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 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 process involves the fusion of male and female gametes?
(A) Pollination
(B) Fertilization
(C) Germination
(D) Implantation
Answer: (B)
Explanation: Fertilization is the union of sperm and egg, resulting in the formation of a zygote. - 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 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 process describes the movement of water across a semi-permeable membrane from low to high solute concentration?
(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. - 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 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 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.