EmSAT Biology 2 — Questions and Answers
Question 1: What is the primary function of the nephron in the kidney?
- Producing hormones such as erythropoietin
- Filtering blood and forming urine (Correct answer)
- Absorbing nutrients from digested food
- Pumping blood through the renal artery
Correct answer: Filtering blood and forming urine
The nephron is the functional unit of the kidney; it filters blood, reabsorbs essential substances, and excretes waste as urine.
Question 2: Which hormone, produced by the pancreas, is responsible for lowering blood glucose levels after a meal?
- Adrenaline
- Thyroxine
- Insulin (Correct answer)
- Cortisol
Correct answer: Insulin
Insulin, secreted by beta cells of the pancreatic islets, promotes glucose uptake by cells and glycogen storage, lowering blood glucose.
Question 3: What is the main role of the alveoli in the human respiratory system?
- Filtering dust and pathogens from inhaled air
- Producing the surfactant that keeps airways open
- Facilitating gas exchange between air and blood (Correct answer)
- Moving air in and out of the lungs through muscular contractions
Correct answer: Facilitating gas exchange between air and blood
Alveoli have thin walls and a dense capillary network that allow O₂ to diffuse into the blood and CO₂ to diffuse out by passive diffusion.
Question 4: In an ecosystem, what term is given to organisms such as plants that produce their own organic food from inorganic materials?
- Consumers
- Decomposers
- Producers (Correct answer)
- Parasites
Correct answer: Producers
Producers (autotrophs) use photosynthesis or chemosynthesis to convert inorganic compounds into organic food, forming the base of food chains.
Question 5: What is the primary function of the lymphatic system in the human body?
- Digesting dietary fats in the small intestine
- Returning interstitial fluid to the bloodstream and supporting immune defence (Correct answer)
- Producing red blood cells in lymph nodes
- Regulating core body temperature through sweating
Correct answer: Returning interstitial fluid to the bloodstream and supporting immune defence
The lymphatic system drains excess tissue fluid back into circulation and contains lymphocytes that mount immune responses against pathogens.
Question 6: What does the term 'biodiversity' refer to in ecology?
- The total biomass of plants in a given ecosystem
- The variety of genes, species, and ecosystems within a defined area (Correct answer)
- The rate of reproduction of the dominant species in a habitat
- The geographic range over which a single species is distributed
Correct answer: The variety of genes, species, and ecosystems within a defined area
Biodiversity encompasses genetic diversity, species diversity, and ecosystem diversity, and is a key measure of ecosystem health and resilience.
Question 7: Which region of the brain controls involuntary vital functions such as breathing rate and heart rate?
- Cerebrum
- Cerebellum
- Medulla oblongata (Correct answer)
- Hypothalamus
Correct answer: Medulla oblongata
The medulla oblongata, located in the brainstem, contains autonomic centres that regulate respiration, cardiac output, and blood pressure.
EmSAT Biology 2
What is the primary function of the nephron in the kidney?