JAMB BIOLOGY – 1. A cell placed in a solution becomes flaccid. Which of the following best explains the condition? A. The solution is hypertonic and water leaves the cell B. The solution is hypotonic and water enters the cell C. The solution is isotonic and there is no net movement of water D. The solution is hypertonic and water enters the cell 2. Which of the following structures is directly responsible for intracellular digestion? A. Ribosome B. Lysosome C. Golgi apparatus D. Mitochondrion 3. In a food chain, energy transfer between trophic levels is inefficient mainly because A. organisms do not feed completely B. energy is lost as heat during respiration C. predators are fewer than prey D. food chains are short 4. Which of the following best describes facilitated diffusion? A. Movement against concentration gradient using ATP B. Movement along concentration gradient without carriers C. Movement along concentration gradient using carrier proteins D. Movement of water across a membrane 5. A plant cell placed in distilled water becomes turgid due to A. diffusion B. osmosis C. active transport D. plasmolysis 6. Which of the following hormones regulates blood glucose level by lowering it? A. Glucagon B. Insulin C. Adrenaline D. Thyroxine 7. Which part of the nephron is primarily responsible for ultrafiltration? A. Loop of Henle B. Distal convoluted tubule C. Bowman’s capsule D. Collecting duct 8. The main function of xylem tissue is to A. transport food B. transport water and minerals C. store starch D. carry out photosynthesis 9. Which of the following best explains why enzymes are specific? A. They are proteins B. Their active sites fit specific substrates C. They are affected by temperature D. They are reusable 10. Which process leads to genetic variation? A. Mitosis B. Binary fission C. Meiosis D. Budding --- 11. During respiration, the stage that yields the highest ATP is A. Glycolysis B. Krebs cycle C. Electron transport chain D. Fermentation 12. Which of the following structures is absent in prokaryotic cells? A. Cell membrane B. Cytoplasm C. Nucleus D. Ribosome 13. A decrease in population size due to limited resources is an example of A. density-independent factor B. density-dependent factor C. ecological succession D. mutation 14. Which vitamin deficiency leads to rickets? A. Vitamin A B. Vitamin B C. Vitamin C D. Vitamin D 15. Which of the following is NOT a function of the liver? A. Detoxification B. Glycogen storage C. Production of insulin D. Bile production 16. The movement of mineral salts into root hairs against concentration gradient requires A. diffusion B. osmosis C. active transport D. transpiration 17. Which part of the brain controls balance? A. Cerebrum B. Cerebellum C. Medulla oblongata D. Hypothalamus 18. Which blood component is mainly responsible for clotting? A. Plasma B. Red blood cells C. Platelets D. White blood cells 19. Which of the following is a decomposer? A. Grasshopper B. Mushroom C. Goat D. Eagle 20. The basic unit of classification is A. kingdom B. phylum C. genus D. species --- 21. Which of the following processes removes nitrogen from the soil? A. Nitrogen fixation B. Nitrification C. Denitrification D. Ammonification 22. The structure that connects the fetus to the mother is the A. placenta B. uterus C. ovary D. cervix 23. Which gas is released during photosynthesis? A. Carbon dioxide B. Oxygen C. Nitrogen D. Hydrogen 24. Which of the following is an example of homologous structures? A. Wings of bird and insect B. Forelimbs of human and bat C. Eyes of octopus and human D. Leaves and roots 25. Which process results in two identical daughter cells? A. Meiosis B. Fertilization C. Mitosis D. Mutation 26. Which organ is responsible for excretion in plants? A. Leaf B. Root C. Stem D. No specialized organ 27. The diffusion of water through a semi-permeable membrane is called A. diffusion B. osmosis C. transpiration D. guttation 28. Which of the following is a vector of malaria? A. Housefly B. Tsetse fly C. Female Anopheles mosquito D. Male mosquito 29. Which of the following best describes mutualism? A. One benefits, one harmed B. Both benefit C. One benefits, one unaffected D. Both harmed 30. Which pigment is responsible for photosynthesis? A. Carotene B. Xanthophyll C. Chlorophyll D. Anthocyanin --- 31. Which factor does NOT affect enzyme activity? A. Temperature B. pH C. Light intensity D. Substrate concentration 32. Which of the following is a function of the skeletal system? A. Respiration B. Movement C. Digestion D. Circulation 33. Which of the following diseases is caused by a virus? A. Tuberculosis B. Cholera C. Measles D. Typhoid 34. Which of the following is a product of anaerobic respiration in humans? A. Ethanol B. Lactic acid C. Carbon dioxide only D. Water 35. Which organelle is known as the control center of the cell? A. Ribosome B. Nucleus C. Mitochondrion D. Vacuole 36. Which of the following is NOT a macronutrient in plants? A. Nitrogen B. Phosphorus C. Potassium D. Zinc 37. Which of the following processes increases genetic diversity? A. Asexual reproduction B. Mitosis C. Crossing over D. Binary fission 38. Which structure in the eye controls the amount of light entering? A. Retina B. Cornea C. Iris D. Lens 39. Which of the following is an abiotic factor? A. Bacteria B. Temperature C. Plants D. Animals 40. Which of the following best explains natural selection? A. Survival of the strongest B. Survival of the biggest C. Survival of organisms best adapted to their environment D. Survival of all organisms equally

Here are the answers to your biology questions: 1. A. The solution is hypertonic and water leaves the cell When a cell becomes flaccid, it has lost water. This occurs when the surrounding solution has a higher solute concentration (is hypertonic*) than the cell's cytoplasm, causing water to move out of the cell by osmosis. 2. B. Lysosome Lysosomes* are organelles that contain digestive enzymes responsible for breaking down waste materials and cellular debris within the cell, a process known as intracellular digestion. 3. B. energy is lost as heat during respiration Energy transfer between trophic levels is inefficient because a significant portion of energy is lost as heat during metabolic processes, particularly respiration