What is the primary function of the C3 cycle in photosynthesis?
The C3 cycle (Calvin cycle) fixes CO2 into a 3-carbon compound, eventually forming glucose using ATP and NADPH.
Which enzyme is responsible for unwinding DNA during replication?
Helicase unwinds the DNA double helix by breaking hydrogen bonds, enabling replication.
What is the role of the sarcoplasmic reticulum in muscle contraction?
The sarcoplasmic reticulum releases calcium ions to trigger muscle contraction by enabling actin-myosin interactions.
Which type of cell signaling involves the release of signaling molecules into the bloodstream?
Endocrine signaling uses hormones released into the bloodstream to target distant cells.
What is the function of the Casparian strip in plant roots?
The Casparian strip in the endodermis controls mineral absorption by forcing selective uptake through cell membranes.
Which part of the brain regulates the body's circadian rhythms?
The suprachiasmatic nucleus (SCN) in the hypothalamus regulates circadian rhythms based on light cues.
What is the term for the process by which cells become specialized to perform specific functions?
Differentiation is the process where cells specialize to perform specific roles, like nerve or muscle cells.
Which type of ecological interaction involves the competition for resources between different species?
Competition occurs when species vie for limited resources, limiting each other’s growth.
What is the function of the proton pump in plant cells?
The proton pump transports protons (H+) across membranes, driving ion and nutrient uptake.
Which organelle is responsible for the degradation of proteins and organelles?
Lysosomes use hydrolytic enzymes to degrade proteins, organelles, and cellular waste.
What is the term for the process by which organisms adapt to their environment through genetic changes?
Evolution involves genetic changes over generations, driven by mechanisms like natural selection.
Which type of muscle fiber is characterized by a high concentration of myoglobin?
Slow-twitch fibers, rich in myoglobin, store oxygen for endurance activities.
What is the function of the HMG-CoA reductase enzyme in cholesterol synthesis?
HMG-CoA reductase catalyzes the rate-limiting step of converting HMG-CoA to mevalonate in cholesterol synthesis.
Which part of the nephron is responsible for the reabsorption of glucose and amino acids?
The proximal convoluted tubule reabsorbs glucose and amino acids from the filtrate.
What is the term for the process by which the body's immune system responds to pathogens?
The immune response involves innate and adaptive immunity to combat pathogens.
Which type of cell junction is characterized by the presence of connexons?
Gap junctions use connexons to allow ion and small molecule passage between cells.
What is the function of the enzyme RuBisCO in the Calvin cycle?
RuBisCO fixes CO2 into 3-phosphoglycerate (3-PGA), a 3-carbon compound, in the Calvin cycle.
Which part of the brain regulates the body's emotional responses?
The amygdala regulates emotions like fear and pleasure and is key in emotional memory.
What is the term for the process by which cells become resistant to antibiotics?
Natural selection favors bacteria with resistance genes, allowing them to survive and reproduce.
Which type of ecological interaction involves one organism benefiting while the other is neither harmed nor benefited?
Commensalism involves one organism benefiting while the other is unaffected, e.g., barnacles on whales.
What is the function of the enzyme DNA polymerase in DNA replication?
DNA polymerase adds nucleotides to synthesize new DNA strands based on the template strand.
Which part of the plant cell is responsible for the synthesis of cellulose?
The plasma membrane houses cellulose synthase enzymes that produce cellulose for the cell wall.
What is the term for the process by which the body's immune system remembers specific pathogens?
Immunological memory enables faster immune responses upon re-exposure to pathogens.
Which type of muscle fiber is most susceptible to fatigue?
Fast-twitch fibers rely on anaerobic respiration, leading to rapid fatigue from lactic acid buildup.
What is the function of the sinoatrial node in the heart?
The sinoatrial node, the heart’s pacemaker, generates impulses to regulate heart rate.
Which part of the nephron is responsible for the concentration of urine?
The Loop of Henle creates a concentration gradient, enabling urine concentration via water reabsorption.
What is the term for the process by which cells communicate with each other through chemical signals?
Cell signaling uses chemical signals like hormones to coordinate cellular activities.
Which type of ecological interaction involves one organism living on or in another and benefiting at its expense?
Parasitism involves a parasite benefiting at the host’s expense, e.g., tapeworms in humans.
What is the function of the enzyme lactase in the small intestine?
Lactase hydrolyzes lactose into glucose and galactose for absorption in the small intestine.
Which part of the brain regulates the body's appetite and satiety?
The hypothalamus regulates appetite and satiety by responding to hunger hormones like ghrelin and leptin.
What is the term for the process by which the body's immune system responds to allergens?
An allergic reaction is a hypersensitive immune response to allergens, involving histamine release.
Which type of cell junction is responsible for maintaining tissue structure?
Desmosomes anchor cells, providing structural support in tissues like skin.
What is the function of the enzyme pyruvate kinase in glycolysis?
Pyruvate kinase catalyzes the conversion of phosphoenolpyruvate to pyruvate, producing ATP in glycolysis.
Which part of the plant cell is responsible for the synthesis of starch?
Amyloplasts synthesize and store starch in plant storage organs like roots and tubers.
What is the term for the process by which cells become specialized to respond to specific stimuli?
Differentiation enables cells to specialize for functions like responding to stimuli, e.g., nerve cells.
Which type of muscle is characterized by the presence of intercalated discs?
Cardiac muscle has intercalated discs for rapid electrical communication, enabling coordinated contractions.
What is the function of the enzyme acetylcholinesterase in the nervous system?
Acetylcholinesterase degrades acetylcholine in the synaptic cleft to terminate neural signals.
Which hormone is responsible for regulating the body's sleep-wake cycle?
Melatonin, produced by the pineal gland, signals sleep in response to darkness, regulating the sleep-wake cycle.
Which type of immunity involves the production of antibodies to fight pathogens?
Humoral immunity involves B cells producing antibodies to target pathogens.
Which ecological interaction involves two organisms benefiting from each other?
Mutualism benefits both organisms, e.g., bees pollinating flowers while feeding on nectar.
Now practice in exam mode
You've studied the answers — now test yourself under real exam conditions with the timer running.
Start JAMB Biology 2025 Quiz