- Which process enables plants to convert solar energy into chemical energy?
A) Respiration
B) Photosynthesis
C) Fermentation
D) Transpiration
Correct Answer: B) Photosynthesis
Explanation: Photosynthesis is the process by which plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. Chlorophyll in chloroplasts captures solar energy, converting it into chemical energy stored in glucose molecules. - If a person is unable to produce insulin, which disease are they most likely to develop?
A) Hypertension
B) Diabetes mellitus
C) Anemia
D) Scurvy
Correct Answer: B) Diabetes mellitus
Explanation: Insulin is a hormone produced by the pancreas that regulates blood sugar. Lack of insulin leads to high blood glucose, resulting in diabetes mellitus. - What is the main function of white blood cells?
A) Oxygen transport
B) Blood clotting
C) Immune defense
D) Hormone production
Correct Answer: C) Immune defense
Explanation: White blood cells (leukocytes) protect the body against infections by identifying and destroying pathogens such as bacteria, viruses, and fungi. - Which mineral is essential for the formation of hemoglobin?
A) Calcium
B) Iron
C) Sodium
D) Potassium
Correct Answer: B) Iron
Explanation: Iron is a key component of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. - What would happen if the stomata of a plant remained closed during daylight hours?
A) Increased photosynthesis
B) Decreased CO₂ intake and reduced photosynthesis
C) Increased transpiration
D) Enhanced sugar transport
Correct Answer: B) Decreased CO₂ intake and reduced photosynthesis
Explanation: Stomata allow CO₂ to enter leaves for photosynthesis. If closed, CO₂ cannot enter, reducing the rate of photosynthesis and also limiting water loss. - Which part of the human brain controls involuntary actions like heartbeat and breathing?
A) Cerebrum
B) Cerebellum
C) Medulla oblongata
D) Thalamus
Correct Answer: C) Medulla oblongata
Explanation: The medulla oblongata regulates vital involuntary functions such as heart rate, breathing, and blood pressure. - What is the role of platelets in blood?
A) Oxygen transport
B) Blood clotting
C) Immune response
D) Hormone transport
Correct Answer: B) Blood clotting
Explanation: Platelets (thrombocytes) are cell fragments that help stop bleeding by forming clots at injury sites. - Which structure in the human eye focuses light onto the retina?
A) Cornea
B) Lens
C) Iris
D) Sclera
Correct Answer: B) Lens
Explanation: The lens is a transparent, flexible structure that adjusts its shape to focus light precisely onto the retina, enabling clear vision. - Which organ is primarily responsible for filtering metabolic wastes from the blood?
A) Liver
B) Kidney
C) Spleen
D) Pancreas
Correct Answer: B) Kidney
Explanation: The kidneys filter blood, removing metabolic wastes, excess salts, and water, which are excreted as urine. - A genetic disorder caused by a single gene mutation affecting hemoglobin is:
A) Down syndrome
B) Sickle cell anemia
C) Turner syndrome
D) Cystic fibrosis
Correct Answer: B) Sickle cell anemia
Explanation: Sickle cell anemia is caused by a mutation in the gene coding for hemoglobin, resulting in abnormally shaped red blood cells that can block blood vessels. - Which vitamin is essential for calcium absorption in the intestine?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D
Correct Answer: D) Vitamin D
Explanation: Vitamin D promotes absorption of calcium from the intestine, crucial for healthy bones and teeth. - Which process describes the movement of molecules from high to low concentration?
A) Active transport
B) Diffusion
C) Endocytosis
D) Exocytosis
Correct Answer: B) Diffusion
Explanation: Diffusion is the passive movement of molecules from an area of higher to lower concentration, driven by the concentration gradient. - Which hormone increases heart rate and prepares the body for “fight or flight”?
A) Insulin
B) Thyroxine
C) Adrenaline
D) Progesterone
Correct Answer: C) Adrenaline
Explanation: Adrenaline (epinephrine), secreted by the adrenal glands, triggers the body’s fight-or-flight response, increasing heart rate and energy availability. - What is the function of the large intestine in the digestive system?
A) Protein digestion
B) Absorption of water and formation of feces
C) Fat emulsification
D) Glucose absorption
Correct Answer: B) Absorption of water and formation of feces
Explanation: The large intestine absorbs water and electrolytes from indigestible food matter, forming solid feces for excretion. - Which type of immunity is acquired after recovering from a disease or receiving a vaccine?
A) Innate immunity
B) Passive immunity
C) Active immunity
D) Artificial immunity
Correct Answer: C) Active immunity
Explanation: Active immunity develops after exposure to a pathogen or vaccination, as the body produces its own antibodies and memory cells for long-term protection. - Which organelle is responsible for packaging and shipping proteins in a cell?
A) Mitochondria
B) Golgi apparatus
C) Ribosome
D) Lysosome
Correct Answer: B) Golgi apparatus
Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids for delivery to their destinations within or outside the cell. - Which disease is caused by a deficiency of insulin?
A) Diabetes mellitus
B) Goiter
C) Scurvy
D) Rickets
Correct Answer: A) Diabetes mellitus
Explanation: Diabetes mellitus is characterized by high blood sugar due to insufficient insulin production or action. - Which element is a major component of proteins and nucleic acids?
A) Phosphorus
B) Nitrogen
C) Potassium
D) Sodium
Correct Answer: B) Nitrogen
Explanation: Nitrogen is found in amino acids (building blocks of proteins) and nucleotides (building blocks of DNA and RNA). - Which process results in the production of four genetically unique daughter cells?
A) Mitosis
B) Meiosis
C) Binary fission
D) Budding
Correct Answer: B) Meiosis
Explanation: Meiosis involves two successive divisions, producing four haploid gametes, each genetically unique due to crossing over and independent assortment. - What is the main function of the phloem in plants?
A) Transport of water
B) Transport of food
C) Storage of starch
D) Photosynthesis
Correct Answer: B) Transport of food
Explanation: Phloem transports sugars and other organic nutrients produced during photosynthesis from leaves to other parts of the plant. - Which structure in the human respiratory system is the site of gas exchange?
A) Bronchi
B) Trachea
C) Alveoli
D) Larynx
Correct Answer: C) Alveoli
Explanation: Alveoli are tiny air sacs in the lungs with thin walls that allow oxygen and carbon dioxide to diffuse between air and blood. - Which hormone regulates the sleep-wake cycle in humans?
A) Melatonin
B) Insulin
C) Adrenaline
D) Thyroxine
Correct Answer: A) Melatonin
Explanation: Melatonin, produced by the pineal gland, controls circadian rhythms and the sleep-wake cycle. - Which type of joint is found in the human knee?
A) Ball-and-socket joint
B) Hinge joint
C) Pivot joint
D) Gliding joint
Correct Answer: B) Hinge joint
Explanation: The knee is a hinge joint, allowing movement in one plane (flexion and extension). - What is the function of the myelin sheath in neurons?
A) Protein synthesis
B) Speeding up nerve impulse transmission
C) Producing neurotransmitters
D) Forming synapses
Correct Answer: B) Speeding up nerve impulse transmission
Explanation: The myelin sheath insulates axons, allowing electrical impulses to travel faster along the neuron. - Which blood component is primarily responsible for fighting infections?
A) Red blood cells
B) Platelets
C) White blood cells
D) Plasma
Correct Answer: C) White blood cells
Explanation: White blood cells (leukocytes) identify and destroy pathogens, providing immune defense. - Which process allows plants to lose excess water through leaves?
A) Guttation
B) Transpiration
C) Respiration
D) Photosynthesis
Correct Answer: B) Transpiration
Explanation: Transpiration is the evaporation of water from plant leaves, mainly through stomata, helping in cooling and nutrient transport. - Which gas is required for aerobic respiration?
A) Carbon dioxide
B) Oxygen
C) Nitrogen
D) Methane
Correct Answer: B) Oxygen
Explanation: Oxygen is essential for aerobic respiration, allowing cells to efficiently extract energy from glucose. - Which structure in the human ear is responsible for balance?
A) Cochlea
B) Semicircular canals
C) Ossicles
D) Eardrum
Correct Answer: B) Semicircular canals
Explanation: The semicircular canals in the inner ear detect changes in head movement and help maintain balance. - Which part of the plant absorbs water and minerals from the soil?
A) Leaf
B) Stem
C) Root
D) Flower
Correct Answer: C) Root
Explanation: Roots anchor the plant and absorb water and minerals from the soil, supplying them to the rest of the plant. - Which hormone is secreted by the pancreas to increase blood sugar?
A) Insulin
B) Glucagon
C) Thyroxine
D) Adrenaline
Correct Answer: B) Glucagon
Explanation: Glucagon raises blood sugar by stimulating the conversion of glycogen to glucose in the liver. - Which molecule is the genetic material in most living organisms?
A) Protein
B) DNA
C) Lipid
D) Carbohydrate
Correct Answer: B) DNA
Explanation: DNA (deoxyribonucleic acid) carries genetic information in most organisms, encoding instructions for growth and function. - Which process describes the movement of water from roots to leaves in plants?
A) Transpiration
B) Respiration
C) Translocation
D) Photosynthesis
Correct Answer: A) Transpiration
Explanation: Transpiration pulls water upward from roots to leaves, driven by evaporation and cohesion of water molecules. - What is the main function of the human liver?
A) Oxygen transport
B) Detoxification and metabolism
C) Blood clotting
D) Hormone production
Correct Answer: B) Detoxification and metabolism
Explanation: The liver detoxifies harmful substances, metabolizes nutrients, produces bile, and stores glycogen. - Which element is essential for thyroid hormone synthesis?
A) Calcium
B) Iodine
C) Iron
D) Magnesium
Correct Answer: B) Iodine
Explanation: Iodine is required for the synthesis of thyroid hormones, which regulate metabolism. Deficiency leads to goiter. - Which part of the human brain is responsible for voluntary movements?
A) Cerebrum
B) Cerebellum
C) Medulla oblongata
D) Hypothalamus
Correct Answer: A) Cerebrum
Explanation: The cerebrum controls voluntary movements, reasoning, memory, and sensory processing. - Which disease is caused by a lack of vitamin C?
A) Rickets
B) Scurvy
C) Pellagra
D) Beriberi
Correct Answer: B) Scurvy
Explanation: Scurvy is caused by vitamin C deficiency, leading to bleeding gums, weakness, and poor wound healing. - Which plant hormone is responsible for cell elongation and phototropism?
A) Ethylene
B) Auxin
C) Gibberellin
D) Cytokinin
Correct Answer: B) Auxin
Explanation: Auxin promotes cell elongation and is responsible for phototropism, the bending of plants toward light. - Which process describes the copying of DNA to produce RNA?
A) Replication
B) Transcription
C) Translation
D) Translocation
Correct Answer: B) Transcription
Explanation: Transcription is the process where a DNA sequence is copied into messenger RNA for protein synthesis. - Which disease is caused by a deficiency of vitamin D in children?
A) Scurvy
B) Rickets
C) Pellagra
D) Night blindness
Correct Answer: B) Rickets
Explanation: Rickets is characterized by weak, soft bones in children due to vitamin D deficiency, which impairs calcium absorption. - Which process in plants releases oxygen as a byproduct?
A) Respiration
B) Photosynthesis
C) Transpiration
D) Fermentation
Correct Answer: B) Photosynthesis
Explanation: During photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct. - Which cell organelle is known as the “powerhouse” of the cell?
A) Nucleus
B) Ribosome
C) Mitochondria
D) Lysosome
Correct Answer: C) Mitochondria
Explanation: Mitochondria generate ATP through cellular respiration, supplying energy for cellular activities. - Which process results in the movement of water through a plant, from roots to leaves, and out through the stomata?
A) Transpiration
B) Translocation
C) Photosynthesis
D) Respiration
Correct Answer: A) Transpiration
Explanation: Transpiration is the loss of water vapor from leaves, which pulls water upward from the roots. - What is the function of the human spleen?
A) Digestion
B) Blood filtration and immune response
C) Hormone production
D) Oxygen transport
Correct Answer: B) Blood filtration and immune response
Explanation: The spleen filters old blood cells, stores white blood cells, and helps fight infection. - Which gas is produced during anaerobic respiration in muscles?
A) Oxygen
B) Carbon dioxide
C) Lactic acid
D) Methane
Correct Answer: C) Lactic acid
Explanation: In the absence of oxygen, muscles perform anaerobic respiration, producing lactic acid as a byproduct. - Which structure in plant cells stores water, nutrients, and waste products?
A) Mitochondria
B) Chloroplast
C) Vacuole
D) Ribosome
Correct Answer: C) Vacuole
Explanation: The vacuole is a large, membrane-bound organelle that stores water, nutrients, and waste, helping maintain cell turgor. - Which blood group is known as the universal donor?
A) A
B) B
C) AB
D) O
Correct Answer: D) O
Explanation: Blood group O negative lacks A and B antigens and Rh factor, making it compatible with all other groups for donation. - Which enzyme is responsible for breaking down proteins in the stomach?
A) Amylase
B) Lipase
C) Pepsin
D) Maltase
Correct Answer: C) Pepsin
Explanation: Pepsin is a protease enzyme that digests proteins into peptides in the acidic environment of the stomach. - Which part of the neuron receives signals from other neurons?
A) Axon
B) Dendrite
C) Myelin sheath
D) Synapse
Correct Answer: B) Dendrite
Explanation: Dendrites are branched extensions of a neuron that receive electrical and chemical signals from other neurons. - Which plant tissue is responsible for the upward transport of water and minerals?
A) Phloem
B) Xylem
C) Cortex
D) Epidermis
Correct Answer: B) Xylem
Explanation: Xylem tissue transports water and minerals from roots to leaves, supporting plant structure as well. - Which hormone is responsible for stimulating milk production after childbirth?
A) Estrogen
B) Progesterone
C) Prolactin
D) Oxytocin
Correct Answer: C) Prolactin
Explanation: Prolactin, secreted by the pituitary gland, stimulates the mammary glands to produce milk following childbirth.