1. Which organelle is primarily responsible for lipid synthesis and detoxification of drugs?
a) Ribosome
b) Rough Endoplasmic Reticulum
c) Smooth Endoplasmic Reticulum
d) Golgi Apparatus
Correct Answer: c) Smooth Endoplasmic Reticulum
Explanation: The smooth endoplasmic reticulum is specialized for lipid synthesis and detoxification of drugs and toxins, especially in liver cells. It does not participate in protein synthesis.
2. What process occurs in the inner mitochondrial membrane to generate ATP?
a) Glycolysis
b) Krebs cycle
c) Electron Transport Chain
d) Fermentation
Correct Answer: c) Electron Transport Chain
Explanation: The electron transport chain, located on the inner mitochondrial membrane, is responsible for generating most of the ATP in aerobic respiration.
3. What distinguishes prokaryotic from eukaryotic cells?
a) Presence of a cell wall
b) Absence of a true nucleus and membrane-bound organelles
c) Presence of DNA
d) Presence of ribosomes
Correct Answer: b) Absence of a true nucleus and membrane-bound organelles
Explanation: Prokaryotic cells lack a true nucleus and membrane-bound organelles, while eukaryotic cells contain both.
4. If a diploid organism has 2n=46, how many chromosomes are in its gametes?
a) 46
b) 23
c) 92
d) 12
Correct Answer: b) 23
Explanation: Gametes are haploid and contain half the number of chromosomes of somatic cells. Therefore, if 2n=46, gametes will have n=23 chromosomes.
5. What is the process of copying DNA information into RNA called?
a) Replication
b) Transcription
c) Translation
d) Transduction
Correct Answer: b) Transcription
Explanation: Transcription is the process by which the genetic information in DNA is copied into RNA.
6. What is true about lysosomes?
a) They synthesize proteins
b) They produce ATP
c) They contain digestive enzymes
d) They synthesize lipids
Correct Answer: c) They contain digestive enzymes
Explanation: Lysosomes are membrane-bound organelles containing hydrolytic enzymes that digest cellular waste and foreign materials.
7. What genotypic ratio results from crossing homozygous dominant and recessive individuals?
a) 1:2:1
b) All homozygous
c) All heterozygous
d) 3:1
Correct Answer: c) All heterozygous
Explanation: Crossing AA (homozygous dominant) with aa (homozygous recessive) results in all offspring being heterozygous (Aa).
8. What is the correct sequence of mitosis?
a) Metaphase, Anaphase, Telophase, Prophase
b) Prophase, Metaphase, Anaphase, Telophase
c) Telophase, Anaphase, Metaphase, Prophase
d) Anaphase, Prophase, Telophase, Metaphase
Correct Answer: b) Prophase, Metaphase, Anaphase, Telophase
Explanation: Mitosis proceeds in the order: Prophase, Metaphase, Anaphase, and Telophase.
9. What is a characteristic of facilitated diffusion?
a) Requires ATP
b) Moves substances against their concentration gradient
c) Uses carrier or channel proteins
d) Only occurs in plant cells
Correct Answer: c) Uses carrier or channel proteins
Explanation: Facilitated diffusion moves substances down their concentration gradient using specific carrier or channel proteins, without requiring ATP.
10. Why was the “one gene, one enzyme” hypothesis modified?
a) Some enzymes are made of multiple polypeptide chains
b) All enzymes are made of DNA
c) One gene can code for many enzymes
d) Enzymes can function without genes
Correct Answer: a) Some enzymes are made of multiple polypeptide chains
Explanation: The hypothesis was changed to “one gene, one polypeptide” because many enzymes are composed of multiple polypeptide chains.
11. Which enzyme is responsible for unwinding DNA during replication?
a) DNA polymerase
b) RNA polymerase
c) Helicase
d) Ligase
Correct Answer: c) Helicase
Explanation: Helicase unwinds the DNA double helix during replication.
12. What is the function of tRNA in protein synthesis?
a) Carries amino acids to the ribosome
b) Forms the ribosome structure
c) Copies DNA into mRNA
d) Joins amino acids together
Correct Answer: a) Carries amino acids to the ribosome
Explanation: Transfer RNA (tRNA) carries specific amino acids to the ribosome for protein synthesis.
13. Which type of cell division results in four genetically unique daughter cells?
a) Mitosis
b) Meiosis
c) Binary fission
d) Budding
Correct Answer: b) Meiosis
Explanation: Meiosis produces four haploid daughter cells, each genetically unique due to crossing over and independent assortment.
14. What is the site of protein synthesis in the cell?
a) Nucleus
b) Mitochondria
c) Ribosome
d) Lysosome
Correct Answer: c) Ribosome
Explanation: Ribosomes are the sites of protein synthesis.
15. Which of the following is a function of the nucleolus?
a) DNA replication
b) Ribosome synthesis
c) ATP production
d) Lipid synthesis
Correct Answer: b) Ribosome synthesis
Explanation: The nucleolus is involved in ribosome synthesis.
16. What is the fluid inside the chloroplast called?
a) Cytoplasm
b) Stroma
c) Matrix
d) Thylakoid lumen
Correct Answer: b) Stroma
Explanation: The stroma is the fluid-filled space inside the chloroplast, where the Calvin cycle occurs.
17. Which organelle is known as the “powerhouse” of the cell?
a) Nucleus
b) Mitochondria
c) Golgi apparatus
d) Endoplasmic reticulum
Correct Answer: b) Mitochondria
Explanation: Mitochondria produce most of the cell’s ATP and are referred to as the powerhouse of the cell.
18. What is the main function of vacuoles in plant cells?
a) Protein synthesis
b) Storage and maintaining turgidity
c) ATP production
d) Digestion
Correct Answer: b) Storage and maintaining turgidity
Explanation: Vacuoles in plant cells store nutrients, waste products, and help maintain cell turgidity.
19. Which process involves the uptake of large particles by the cell?
a) Diffusion
b) Osmosis
c) Phagocytosis
d) Facilitated diffusion
Correct Answer: c) Phagocytosis
Explanation: Phagocytosis is the process by which cells engulf large particles or whole cells.
20. What is the function of the plasma membrane?
a) Protects and supports the cell
b) Regulates entry and exit of substances
c) Synthesizes proteins
d) Produces energy
Correct Answer: b) Regulates entry and exit of substances
Explanation: The plasma membrane regulates the movement of substances in and out of the cell.
21. Which brain region controls vital involuntary functions?
a) Cerebrum
b) Cerebellum
c) Medulla Oblongata
d) Hypothalamus
Correct Answer: c) Medulla Oblongata
Explanation: The medulla oblongata regulates vital involuntary functions such as breathing and heart rate.
22. Where are most nutrients absorbed in the digestive tract?
a) Stomach
b) Small Intestine
c) Large Intestine
d) Esophagus
Correct Answer: b) Small Intestine
Explanation: The small intestine is the main site of nutrient absorption due to its villi and microvilli.
23. What is the main function of red blood cells?
a) Fight infection
b) Transport oxygen
c) Form blood clots
d) Produce hormones
Correct Answer: b) Transport oxygen
Explanation: Red blood cells contain hemoglobin, which binds and transports oxygen.
24. What does pepsin do?
a) Digests carbohydrates
b) Digests proteins
c) Emulsifies fats
d) Neutralizes stomach acid
Correct Answer: b) Digests proteins
Explanation: Pepsin is a protease that breaks down proteins in the stomach.
25. What is the heart’s natural pacemaker?
a) AV node
b) SA node
c) Bundle of His
d) Purkinje fibers
Correct Answer: b) SA node
Explanation: The sinoatrial (SA) node initiates the heartbeat, making it the natural pacemaker.
26. Which gland regulates blood calcium?
a) Thyroid
b) Parathyroid
c) Adrenal
d) Pituitary
Correct Answer: b) Parathyroid
Explanation: The parathyroid gland secretes parathyroid hormone, which increases blood calcium.
27. Where does blood filtration occur in the kidney?
a) Loop of Henle
b) Glomerulus
c) Collecting duct
d) Renal pelvis
Correct Answer: b) Glomerulus
Explanation: The glomerulus is the site of blood filtration in the nephron.
28. Which sense uses mechanoreceptors?
a) Vision
b) Hearing
c) Taste
d) Smell
Correct Answer: b) Hearing
Explanation: Hearing relies on mechanoreceptors (hair cells) in the inner ear.
29. What is the functional unit of the nervous system?
a) Nephron
b) Neuron
c) Muscle fiber
d) Red blood cell
Correct Answer: b) Neuron
Explanation: The neuron is the basic functional unit of the nervous system.
30. Which hormone triggers the ‘fight or flight’ response?
a) Insulin
b) Adrenaline (Epinephrine)
c) Thyroxine
d) Estrogen
Correct Answer: b) Adrenaline (Epinephrine)
Explanation: Adrenaline prepares the body for rapid action in response to stress.
31. Where does gas exchange occur in the lungs?
a) Bronchi
b) Trachea
c) Alveoli
d) Bronchioles
Correct Answer: c) Alveoli
Explanation: Alveoli are the sites of gas exchange in the lungs.
32. What forms blood clots at injury sites?
a) White blood cells
b) Red blood cells
c) Platelets
d) Plasma
Correct Answer: c) Platelets
Explanation: Platelets aggregate at injury sites to form clots.
33. What is the largest gland in the body?
a) Pancreas
b) Thyroid
c) Liver
d) Adrenal
Correct Answer: c) Liver
Explanation: The liver is the largest gland and performs many metabolic functions.
34. Which is an example of a cartilaginous joint?
a) Skull sutures
b) Knee joint
c) Intervertebral discs
d) Elbow joint
Correct Answer: c) Intervertebral discs
Explanation: Intervertebral discs between vertebrae are cartilaginous joints.
35. What is the process of breaking glycogen into glucose called?
a) Glycolysis
b) Glycogenesis
c) Glycogenolysis
d) Gluconeogenesis
Correct Answer: c) Glycogenolysis
Explanation: Glycogenolysis is the breakdown of glycogen into glucose.
36. Which vitamin is synthesized by the skin in the presence of sunlight?
a) Vitamin A
b) Vitamin D
c) Vitamin E
d) Vitamin K
Correct Answer: b) Vitamin D
Explanation: Vitamin D is synthesized in the skin in the presence of sunlight.
37. Which part of the brain is responsible for memory and learning?
a) Cerebrum
b) Cerebellum
c) Medulla oblongata
d) Hypothalamus
Correct Answer: a) Cerebrum
Explanation: The cerebrum is responsible for memory, learning, and conscious thought.
38. What is the function of bile?
a) Digests proteins
b) Emulsifies fats
c) Digests carbohydrates
d) Neutralizes stomach acid
Correct Answer: b) Emulsifies fats
Explanation: Bile emulsifies fats, aiding in their digestion.
39. Which hormone is produced by the pancreas and regulates blood sugar?
a) Insulin
b) Thyroxine
c) Adrenaline
d) Progesterone
Correct Answer: a) Insulin
Explanation: Insulin is produced by the pancreas and regulates blood glucose levels.
40. What is the function of hemoglobin?
a) Transport oxygen
b) Fight infection
c) Clot blood
d) Digest proteins
Correct Answer: a) Transport oxygen
Explanation: Hemoglobin in red blood cells transports oxygen.
41. Which plant hormone promotes cell elongation and phototropism?
a) Auxin
b) Gibberellin
c) Cytokinin
d) Ethylene
Correct Answer: a) Auxin
Explanation: Auxin promotes cell elongation and phototropism.
42. What structure is involved in transpiration?
a) Root hairs
b) Stomata
c) Xylem
d) Phloem
Correct Answer: b) Stomata
Explanation: Stomata are involved in transpiration and gas exchange.
43. Which macronutrient is crucial for chlorophyll and ATP?
a) Nitrogen
b) Potassium
c) Magnesium
d) Phosphorus
Correct Answer: c) Magnesium
Explanation: Magnesium is a component of chlorophyll and is required for ATP function.
44. What do light-dependent reactions produce for the Calvin cycle?
a) Glucose and oxygen
b) ATP and NADPH
c) Water and carbon dioxide
d) Oxygen and water
Correct Answer: b) ATP and NADPH
Explanation: Light-dependent reactions produce ATP and NADPH for the Calvin cycle.
45. What is the male reproductive part of a flower?
a) Pistil
b) Stamen
c) Petal
d) Sepal
Correct Answer: b) Stamen
Explanation: The stamen is the male reproductive organ of a flower.
46. What is the movement of water across a membrane called?
a) Diffusion
b) Active transport
c) Osmosis
d) Facilitated diffusion
Correct Answer: c) Osmosis
Explanation: Osmosis is the movement of water across a semipermeable membrane.
47. What is the ploidy of endosperm in angiosperms?
a) Haploid (n)
b) Diploid (2n)
c) Triploid (3n)
d) Tetraploid (4n)
Correct Answer: c) Triploid (3n)
Explanation: Endosperm in angiosperms is triploid, formed by the fusion of one sperm with two polar nuclei.
48. Which vascular tissue transports water and minerals in plants?
a) Xylem
b) Phloem
c) Cambium
d) Epidermis
Correct Answer: a) Xylem
Explanation: Xylem transports water and minerals from roots to shoots.
49. What is the main function of the root system in plants?
a) Photosynthesis
b) Anchorage and absorption
c) Reproduction
d) Transpiration
Correct Answer: b) Anchorage and absorption
Explanation: Roots anchor the plant and absorb water and minerals.
50. Which process releases oxygen during photosynthesis?
a) Calvin cycle
b) Light-dependent reactions
c) Glycolysis
d) Krebs cycle
Correct Answer: b) Light-dependent reactions
Explanation: Oxygen is released during the light-dependent reactions of photosynthesis.