- Which organelle is known as the “suicide bag” of the cell?
A) Mitochondria
B) Lysosome
C) Golgi apparatus
D) Ribosome
Correct Answer: B) Lysosome
Explanation: Lysosomes contain hydrolytic enzymes that digest worn-out cell parts and foreign substances. If they rupture, their enzymes can destroy the cell, hence the nickname “suicide bag.” - What is the genetic material in most bacteria?
A) Linear DNA in nucleus
B) Circular DNA in cytoplasm
C) RNA only
D) Protein
Correct Answer: B) Circular DNA in cytoplasm
Explanation: Most bacteria have a single, circular DNA molecule located in the cytoplasm, not enclosed in a nucleus. - Which process describes the conversion of glucose to pyruvate?
A) Krebs cycle
B) Glycolysis
C) Fermentation
D) Electron transport chain
Correct Answer: B) Glycolysis
Explanation: Glycolysis is the first step in cellular respiration, breaking one glucose molecule into two pyruvate molecules, producing ATP and NADH. - What is the function of guard cells in plants?
A) Absorb water
B) Regulate opening and closing of stomata
C) Transport food
D) Store starch
Correct Answer: B) Regulate opening and closing of stomata
Explanation: Guard cells surround each stoma and control its opening and closing, thus regulating gas exchange and water loss. - In humans, which chromosome pair determines sex?
A) 1st
B) 7th
C) 23rd
D) 22nd
Correct Answer: C) 23rd
Explanation: The 23rd pair of chromosomes are sex chromosomes (XX for females, XY for males) and determine an individual’s sex. - Which plant pigment is essential for photosynthesis?
A) Carotene
B) Xanthophyll
C) Chlorophyll
D) Anthocyanin
Correct Answer: C) Chlorophyll
Explanation: Chlorophyll absorbs sunlight and is crucial for converting light energy into chemical energy during photosynthesis. - Which enzyme is secreted by the stomach to digest proteins?
A) Amylase
B) Pepsin
C) Lipase
D) Maltase
Correct Answer: B) Pepsin
Explanation: Pepsin is a protease enzyme that breaks down proteins into peptides in the acidic environment of the stomach. - What is the main function of red bone marrow?
A) Store fat
B) Produce blood cells
C) Support joints
D) Store calcium
Correct Answer: B) Produce blood cells
Explanation: Red bone marrow is the primary site of new blood cell production, including red cells, white cells, and platelets. - Which process involves the movement of substances against their concentration gradient?
A) Passive diffusion
B) Active transport
C) Osmosis
D) Facilitated diffusion
Correct Answer: B) Active transport
Explanation: Active transport requires energy (ATP) to move substances from low to high concentration, against the gradient. - Which vitamin is essential for blood clotting?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin K
Correct Answer: D) Vitamin K
Explanation: Vitamin K is necessary for the synthesis of clotting factors in the liver, preventing excessive bleeding. - Which part of the human brain regulates body temperature?
A) Cerebellum
B) Medulla oblongata
C) Hypothalamus
D) Cerebrum
Correct Answer: C) Hypothalamus
Explanation: The hypothalamus acts as the body’s thermostat, regulating temperature, hunger, thirst, and other autonomic functions. - Which structure in the heart prevents backflow of blood?
A) Septum
B) Valves
C) Atrium
D) Aorta
Correct Answer: B) Valves
Explanation: Heart valves (tricuspid, bicuspid, semilunar) ensure unidirectional flow of blood and prevent backflow. - What is the main function of the human large intestine?
A) Digestion of proteins
B) Absorption of water and minerals
C) Production of insulin
D) Storage of bile
Correct Answer: B) Absorption of water and minerals
Explanation: The large intestine absorbs water and minerals from indigestible food residue, forming solid feces. - Which hormone is responsible for lowering blood glucose levels?
A) Glucagon
B) Insulin
C) Adrenaline
D) Thyroxine
Correct Answer: B) Insulin
Explanation: Insulin, secreted by the pancreas, facilitates the uptake of glucose by cells, lowering blood sugar levels. - Which process describes the fusion of male and female gametes in plants?
A) Germination
B) Fertilization
C) Pollination
D) Fragmentation
Correct Answer: B) Fertilization
Explanation: Fertilization is the union of male (pollen) and female (egg) gametes, forming a zygote. - What is the role of ribosomes in a cell?
A) Energy production
B) Protein synthesis
C) Lipid storage
D) DNA replication
Correct Answer: B) Protein synthesis
Explanation: Ribosomes are molecular machines that translate mRNA into proteins, essential for cell structure and function. - Which blood group is considered the universal recipient?
A) O negative
B) A positive
C) AB positive
D) B negative
Correct Answer: C) AB positive
Explanation: AB positive individuals can receive blood from any group due to the presence of both A and B antigens and the Rh factor. - What is the function of the mitochondria?
A) Protein synthesis
B) ATP (energy) production
C) Storage of waste
D) Photosynthesis
Correct Answer: B) ATP (energy) production
Explanation: Mitochondria are the site of aerobic respiration, generating ATP, the cell’s main energy currency. - Which element is a key component of thyroid hormones?
A) Calcium
B) Iron
C) Iodine
D) Potassium
Correct Answer: C) Iodine
Explanation: Iodine is required for the synthesis of thyroid hormones (T3, T4), which regulate metabolism. - Which process is responsible for the exchange of gases in the lungs?
A) Filtration
B) Diffusion
C) Active transport
D) Osmosis
Correct Answer: B) Diffusion
Explanation: Oxygen and carbon dioxide move across the alveolar membrane by diffusion, from high to low concentration. - Which part of the plant is responsible for anchoring it to the soil?
A) Stem
B) Leaf
C) Root
D) Flower
Correct Answer: C) Root
Explanation: Roots anchor the plant, absorb water and minerals, and sometimes store food. - Which disease is caused by a deficiency of iron?
A) Scurvy
B) Anemia
C) Rickets
D) Goiter
Correct Answer: B) Anemia
Explanation: Iron deficiency leads to anemia, characterized by fatigue and weakness due to reduced oxygen-carrying capacity of blood. - Which type of blood vessel carries blood away from the heart?
A) Vein
B) Artery
C) Capillary
D) Venule
Correct Answer: B) Artery
Explanation: Arteries carry blood away from the heart to various parts of the body, usually oxygenated except the pulmonary artery. - What is the function of the human diaphragm?
A) Pump blood
B) Aid in breathing
C) Produce hormones
D) Filter toxins
Correct Answer: B) Aid in breathing
Explanation: The diaphragm contracts and flattens to enlarge the chest cavity, drawing air into the lungs during inhalation. - Which part of the flower produces pollen?
A) Stigma
B) Ovary
C) Anther
D) Style
Correct Answer: C) Anther
Explanation: The anther, part of the stamen, produces and releases pollen grains containing male gametes. - Which organ secretes bile?
A) Pancreas
B) Liver
C) Gallbladder
D) Stomach
Correct Answer: B) Liver
Explanation: The liver produces bile, which is stored in the gallbladder and released into the small intestine for fat digestion. - What is the function of the cornea in the human eye?
A) Focus light
B) Produce tears
C) Control pupil size
D) Transmit nerve impulses
Correct Answer: A) Focus light
Explanation: The cornea is the transparent front part of the eye that bends and focuses incoming light onto the lens. - Which hormone is responsible for secondary sexual characteristics in males?
A) Estrogen
B) Testosterone
C) Progesterone
D) Insulin
Correct Answer: B) Testosterone
Explanation: Testosterone, produced by the testes, promotes development of male secondary sexual characteristics such as facial hair and deep voice. - Which process describes the breakdown of glucose in the absence of oxygen?
A) Aerobic respiration
B) Anaerobic respiration
C) Photosynthesis
D) Chemosynthesis
Correct Answer: B) Anaerobic respiration
Explanation: Anaerobic respiration (fermentation) breaks down glucose without oxygen, producing less ATP and byproducts like lactic acid or ethanol. - Which vitamin deficiency causes rickets in children?
A) Vitamin A
B) Vitamin C
C) Vitamin D
D) Vitamin K
Correct Answer: C) Vitamin D
Explanation: Vitamin D is essential for calcium absorption and bone health. Deficiency leads to rickets, causing weak and deformed bones in children. - Which structure in the neuron transmits impulses away from the cell body?
A) Dendrite
B) Axon
C) Synapse
D) Soma
Correct Answer: B) Axon
Explanation: The axon is a long fiber that carries nerve impulses away from the cell body toward other neurons or muscles. - Which process describes the movement of water through a semi-permeable membrane from low to high solute concentration?
A) Diffusion
B) Active transport
C) Osmosis
D) Endocytosis
Correct Answer: C) Osmosis
Explanation: Osmosis is the passive movement of water from an area of low solute concentration to high solute concentration across a semi-permeable membrane. - Which disease is caused by a deficiency of vitamin B1 (thiamine)?
A) Pellagra
B) Beriberi
C) Scurvy
D) Rickets
Correct Answer: B) Beriberi
Explanation: Beriberi is a nervous system disorder caused by thiamine deficiency, leading to weakness and heart problems. - Which organ filters old red blood cells from the blood?
A) Liver
B) Spleen
C) Kidney
D) Pancreas
Correct Answer: B) Spleen
Explanation: The spleen removes old or damaged red blood cells and helps fight infection. - Which hormone stimulates the release of milk during breastfeeding?
A) Prolactin
B) Oxytocin
C) Estrogen
D) Progesterone
Correct Answer: B) Oxytocin
Explanation: Oxytocin triggers the contraction of muscles around mammary glands, allowing milk to be ejected during breastfeeding. - What is the function of the human epiglottis?
A) Produce sound
B) Prevent food from entering the windpipe
C) Increase lung capacity
D) Filter dust
Correct Answer: B) Prevent food from entering the windpipe
Explanation: The epiglottis is a flap that covers the trachea during swallowing, preventing food from entering the airway. - Which element is essential for hemoglobin synthesis?
A) Calcium
B) Iron
C) Zinc
D) Magnesium
Correct Answer: B) Iron
Explanation: Iron is a key component of hemoglobin, necessary for oxygen transport in the blood. - Which organ is responsible for the production of urea?
A) Kidney
B) Liver
C) Pancreas
D) Spleen
Correct Answer: B) Liver
Explanation: The liver converts ammonia, a toxic byproduct of protein metabolism, into urea, which is then excreted by the kidneys. - Which part of the human skeleton protects the brain?
A) Rib cage
B) Pelvis
C) Skull
D) Vertebral column
Correct Answer: C) Skull
Explanation: The skull encases and protects the brain from injury. - Which process describes the transfer of pollen from anther to stigma?
A) Fertilization
B) Germination
C) Pollination
D) Seed dispersal
Correct Answer: C) Pollination
Explanation: Pollination is the transfer of pollen from the male anther to the female stigma, enabling fertilization in plants. - Which gland secretes growth hormone?
A) Thyroid gland
B) Pituitary gland
C) Adrenal gland
D) Pineal gland
Correct Answer: B) Pituitary gland
Explanation: The pituitary gland, located at the base of the brain, secretes growth hormone, which stimulates body growth and cell reproduction. - What is the function of the human alveoli?
A) Absorb nutrients
B) Exchange gases
C) Filter blood
D) Produce mucus
Correct Answer: B) Exchange gases
Explanation: Alveoli are tiny air sacs in the lungs where oxygen enters the blood and carbon dioxide is removed. - Which vitamin is essential for vision and immune function?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D
Correct Answer: A) Vitamin A
Explanation: Vitamin A is necessary for the formation of visual pigments and maintaining healthy immune function. - Which organ produces digestive enzymes and hormones like insulin?
A) Liver
B) Pancreas
C) Gallbladder
D) Spleen
Correct Answer: B) Pancreas
Explanation: The pancreas produces digestive enzymes for the small intestine and hormones (insulin, glucagon) for blood sugar regulation. - Which plant hormone is responsible for seed dormancy?
A) Auxin
B) Gibberellin
C) Abscisic acid
D) Ethylene
Correct Answer: C) Abscisic acid
Explanation: Abscisic acid induces and maintains seed dormancy, preventing germination under unfavorable conditions. - Which process produces lactic acid in muscles during intense exercise?
A) Aerobic respiration
B) Anaerobic respiration
C) Photosynthesis
D) Chemosynthesis
Correct Answer: B) Anaerobic respiration
Explanation: When oxygen is scarce, muscles switch to anaerobic respiration, producing lactic acid as a byproduct. - Which structure in the heart receives deoxygenated blood from the body?
A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle
Correct Answer: B) Right atrium
Explanation: The right atrium receives deoxygenated blood from the body via the superior and inferior vena cava. - Which mineral is essential for bone and teeth formation?
A) Sodium
B) Potassium
C) Calcium
D) Iron
Correct Answer: C) Calcium
Explanation: Calcium is a major component of bones and teeth, providing strength and structure. - Which enzyme converts starch to maltose in saliva?
A) Pepsin
B) Amylase
C) Lipase
D) Lactase
Correct Answer: B) Amylase
Explanation: Amylase, present in saliva, breaks down starch into maltose, beginning the process of carbohydrate digestion. - Which blood vessel supplies oxygenated blood to the heart muscle?
A) Pulmonary vein
B) Coronary artery
C) Aorta
D) Carotid artery
Correct Answer: B) Coronary artery
Explanation: The coronary arteries branch from the aorta and supply oxygen-rich blood directly to the heart muscle, ensuring its function.