jamb
2025
biology
Q1. What is the primary function of the C3 cycle in photosynthesis?
ATo fix CO2 into glucose
BTo regenerate RuBP
CTo produce ATP and NADPH
DTo synthesize proteins
The C3 cycle (Calvin cycle) fixes CO2 into a 3-carbon compound, eventually forming glucose using ATP and NADPH.
Generating AI explanation...
jamb
2025
biology
Q2. Which enzyme is responsible for unwinding DNA during replication?
AHelicase
BPolymerase
CLigase
DRestriction endonuclease
Helicase unwinds the DNA double helix by breaking hydrogen bonds, enabling replication.
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jamb
2025
biology
Q3. What is the role of the sarcoplasmic reticulum in muscle contraction?
ATo release calcium ions
BTo regulate muscle tone
CTo synthesize ATP
DTo store glycogen
The sarcoplasmic reticulum releases calcium ions to trigger muscle contraction by enabling actin-myosin interactions.
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jamb
2025
biology
Q4. Which type of cell signaling involves the release of signaling molecules into the bloodstream?
AEndocrine signaling
BParacrine signaling
CAutocrine signaling
DJuxtacrine signaling
Endocrine signaling uses hormones released into the bloodstream to target distant cells.
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jamb
2025
biology
Q5. What is the function of the Casparian strip in plant roots?
ATo regulate water uptake
BTo control mineral absorption
CTo synthesize suberin
DTo facilitate gas exchange
The Casparian strip in the endodermis controls mineral absorption by forcing selective uptake through cell membranes.
Generating AI explanation...
jamb
2025
biology
Q6. Which part of the brain regulates the body's circadian rhythms?
ASuprachiasmatic nucleus
BHypothalamus
CThalamus
DCerebral cortex
The suprachiasmatic nucleus (SCN) in the hypothalamus regulates circadian rhythms based on light cues.
Generating AI explanation...
jamb
2025
biology
Q7. What is the term for the process by which cells become specialized to perform specific functions?
ADifferentiation
BMorphogenesis
CHistogenesis
DOrganogenesis
Differentiation is the process where cells specialize to perform specific roles, like nerve or muscle cells.
Generating AI explanation...
jamb
2025
biology
Q8. Which type of ecological interaction involves the competition for resources between different species?
APredation
BCompetition
CMutualism
DCommensalism
Competition occurs when species vie for limited resources, limiting each other’s growth.
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jamb
2025
biology
Q9. What is the function of the proton pump in plant cells?
ATo regulate pH levels
BTo generate ATP
CTo transport ions
DTo synthesize proteins
The proton pump transports protons (H+) across membranes, driving ion and nutrient uptake.
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jamb
2025
biology
Q10. Which organelle is responsible for the degradation of proteins and organelles?
ALysosome
BProteasome
CPeroxisome
DGolgi apparatus
Lysosomes use hydrolytic enzymes to degrade proteins, organelles, and cellular waste.
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jamb
2025
biology
Q11. What is the term for the process by which organisms adapt to their environment through genetic changes?
AEvolution
BNatural selection
CAdaptation
DMutation
Evolution involves genetic changes over generations, driven by mechanisms like natural selection.
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jamb
2025
biology
Q12. Which type of muscle fiber is characterized by a high concentration of myoglobin?
AFast-twitch fibers
BSlow-twitch fibers
CIntermediate fibers
DSmooth muscle fibers
Slow-twitch fibers, rich in myoglobin, store oxygen for endurance activities.
Generating AI explanation...
jamb
2025
biology
Q13. What is the function of the HMG-CoA reductase enzyme in cholesterol synthesis?
ATo catalyze the conversion of HMG-CoA to mevalonate
BTo regulate gene expression for cholesterol synthesis
CTo transport cholesterol in the bloodstream
DTo synthesize bile acids
HMG-CoA reductase catalyzes the rate-limiting step of converting HMG-CoA to mevalonate in cholesterol synthesis.
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jamb
2025
biology
Q14. Which part of the nephron is responsible for the reabsorption of glucose and amino acids?
AProximal convoluted tubule
BLoop of Henle
CDistal convoluted tubule
DCollecting duct
The proximal convoluted tubule reabsorbs glucose and amino acids from the filtrate.
Generating AI explanation...
jamb
2025
biology
Q15. What is the term for the process by which the body's immune system responds to pathogens?
AImmune response
BInflammation
CPhagocytosis
DImmunological tolerance
The immune response involves innate and adaptive immunity to combat pathogens.
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jamb
2025
biology
Q16. Which type of cell junction is characterized by the presence of connexons?
ATight junctions
BAdherens junctions
CGap junctions
DDesmosomes
Gap junctions use connexons to allow ion and small molecule passage between cells.
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jamb
2025
biology
Q17. What is the function of the enzyme RuBisCO in the Calvin cycle?
ATo fix CO2 into a 3-carbon compound
BTo regenerate RuBP
CTo produce ATP and NADPH
DTo synthesize proteins
RuBisCO fixes CO2 into 3-phosphoglycerate (3-PGA), a 3-carbon compound, in the Calvin cycle.
Generating AI explanation...
jamb
2025
biology
Q18. Which part of the brain regulates the body's emotional responses?
AAmygdala
BHippocampus
CCerebral cortex
DBrainstem
The amygdala regulates emotions like fear and pleasure and is key in emotional memory.
Generating AI explanation...
jamb
2025
biology
Q19. What is the term for the process by which cells become resistant to antibiotics?
AMutation
BGene expression
CHorizontal gene transfer
DNatural selection
Natural selection favors bacteria with resistance genes, allowing them to survive and reproduce.
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jamb
2025
biology
Q20. Which type of ecological interaction involves one organism benefiting while the other is neither harmed nor benefited?
APredation
BCompetition
CMutualism
DCommensalism
Commensalism involves one organism benefiting while the other is unaffected, e.g., barnacles on whales.
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jamb
2025
biology
Q21. What is the function of the enzyme DNA polymerase in DNA replication?
ATo unwind DNA
BTo synthesize new DNA strands
CTo repair damaged DNA
DTo cut DNA
DNA polymerase adds nucleotides to synthesize new DNA strands based on the template strand.
Generating AI explanation...
jamb
2025
biology
Q22. Which part of the plant cell is responsible for the synthesis of cellulose?
AGolgi apparatus
BEndoplasmic reticulum
CPlasma membrane
DCell wall
The plasma membrane houses cellulose synthase enzymes that produce cellulose for the cell wall.
Generating AI explanation...
jamb
2025
biology
Q23. What is the term for the process by which the body's immune system remembers specific pathogens?
AImmunological memory
BImmune response
CInflammation
DPhagocytosis
Immunological memory enables faster immune responses upon re-exposure to pathogens.
Generating AI explanation...
jamb
2025
biology
Q24. Which type of muscle fiber is most susceptible to fatigue?
AFast-twitch fibers
BSlow-twitch fibers
CIntermediate fibers
DSmooth muscle fibers
Fast-twitch fibers rely on anaerobic respiration, leading to rapid fatigue from lactic acid buildup.
Generating AI explanation...
jamb
2025
biology
Q25. What is the function of the sinoatrial node in the heart?
ATo regulate heart rate
BTo control blood pressure
CTo pump blood
DTo filter blood
The sinoatrial node, the heart’s pacemaker, generates impulses to regulate heart rate.
Generating AI explanation...
jamb
2025
biology
Q26. Which part of the nephron is responsible for the concentration of urine?
AProximal convoluted tubule
BLoop of Henle
CDistal convoluted tubule
DCollecting duct
The Loop of Henle creates a concentration gradient, enabling urine concentration via water reabsorption.
Generating AI explanation...
jamb
2025
biology
Q27. What is the term for the process by which cells communicate with each other through chemical signals?
ACell signaling
BCell division
CCell differentiation
DCell adhesion
Cell signaling uses chemical signals like hormones to coordinate cellular activities.
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jamb
2025
biology
Q28. Which type of ecological interaction involves one organism living on or in another and benefiting at its expense?
AParasitism
BPredation
CCompetition
DMutualism
Parasitism involves a parasite benefiting at the host’s expense, e.g., tapeworms in humans.
Generating AI explanation...
jamb
2025
biology
Q29. What is the function of the enzyme lactase in the small intestine?
ATo break down lactose into glucose and galactose
BTo synthesize lactose from glucose and galactose
CTo regulate blood sugar levels
DTo absorb lactose
Lactase hydrolyzes lactose into glucose and galactose for absorption in the small intestine.
Generating AI explanation...
jamb
2025
biology
Q30. Which part of the brain regulates the body's appetite and satiety?
AHypothalamus
BThalamus
CCerebral cortex
DBrainstem
The hypothalamus regulates appetite and satiety by responding to hunger hormones like ghrelin and leptin.
Generating AI explanation...
jamb
2025
biology
Q31. What is the term for the process by which the body's immune system responds to allergens?
AAllergic reaction
BImmune response
CInflammation
DImmunological tolerance
An allergic reaction is a hypersensitive immune response to allergens, involving histamine release.
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jamb
2025
biology
Q32. Which type of cell junction is responsible for maintaining tissue structure?
ATight junctions
BAdherens junctions
CGap junctions
DDesmosomes
Desmosomes anchor cells, providing structural support in tissues like skin.
Generating AI explanation...
jamb
2025
biology
Q33. What is the function of the enzyme pyruvate kinase in glycolysis?
ATo convert phosphoenolpyruvate to pyruvate
BTo convert glucose to glucose-6-phosphate
CTo regulate glycolysis
DTo synthesize ATP
Pyruvate kinase catalyzes the conversion of phosphoenolpyruvate to pyruvate, producing ATP in glycolysis.
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jamb
2025
biology
Q34. Which part of the plant cell is responsible for the synthesis of starch?
AChloroplast
BAmyloplast
CGolgi apparatus
DEndoplasmic reticulum
Amyloplasts synthesize and store starch in plant storage organs like roots and tubers.
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jamb
2025
biology
Q35. What is the term for the process by which cells become specialized to respond to specific stimuli?
ADifferentiation
BSensitization
CAdaptation
DIrritability
Differentiation enables cells to specialize for functions like responding to stimuli, e.g., nerve cells.
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jamb
2025
biology
Q36. Which type of muscle is characterized by the presence of intercalated discs?
ASkeletal muscle
BSmooth muscle
CCardiac muscle
DStriated muscle
Cardiac muscle has intercalated discs for rapid electrical communication, enabling coordinated contractions.
Generating AI explanation...
jamb
2025
biology
Q37. What is the function of the enzyme acetylcholinesterase in the nervous system?
ATo synthesize acetylcholine
BTo break down acetylcholine
CTo regulate muscle contraction
DTo transmit nerve impulses
Acetylcholinesterase degrades acetylcholine in the synaptic cleft to terminate neural signals.
Generating AI explanation...
jamb
2025
biology
Q38. Which hormone is responsible for regulating the body's sleep-wake cycle?
AMelatonin
BCortisol
CAdrenaline
DThyroxine
Melatonin, produced by the pineal gland, signals sleep in response to darkness, regulating the sleep-wake cycle.
Generating AI explanation...
jamb
2025
biology
Q39. Which type of immunity involves the production of antibodies to fight pathogens?
ACell-mediated immunity
BHumoral immunity
CInnate immunity
DPassive immunity
Humoral immunity involves B cells producing antibodies to target pathogens.
Generating AI explanation...
jamb
2025
biology
Q40. Which ecological interaction involves two organisms benefiting from each other?
AMutualism
BCommensalism
CParasitism
DPredation
Mutualism benefits both organisms, e.g., bees pollinating flowers while feeding on nectar.
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