GCSE Biology 3 — Questions and Answers
Question 1: Which type of neuron carries impulses from the central nervous system to effectors such as muscles?
- Sensory neuron
- Relay neuron
- Motor neuron (Correct answer)
- Receptor neuron
Correct answer: Motor neuron
Motor neurons transmit electrical impulses from the CNS to effectors, causing muscles to contract or glands to secrete.
Question 2: In a food web, what happens to the population of primary consumers if a large number of top predators are removed?
- Primary consumer population decreases
- Primary consumer population increases (Correct answer)
- Primary consumer population remains stable
- Producer population increases immediately
Correct answer: Primary consumer population increases
Removing top predators reduces predation pressure on primary consumers, allowing their population to increase — a classic trophic cascade.
Question 3: What is the function of amylase in digestion?
- It breaks down proteins into amino acids
- It emulsifies fats into smaller droplets
- It breaks down starch into maltose (Correct answer)
- It absorbs glucose into the bloodstream
Correct answer: It breaks down starch into maltose
Amylase is a carbohydrase enzyme that catalyses the hydrolysis of starch into maltose, produced in the salivary glands and pancreas.
Question 4: Which process describes the movement of water from a region of high water potential to low water potential across a partially permeable membrane?
- Active transport
- Diffusion
- Osmosis (Correct answer)
- Facilitated diffusion
Correct answer: Osmosis
Osmosis is the net movement of water molecules across a partially permeable membrane down a water potential gradient.
Question 5: What is the main function of the lymphatic system in relation to immunity?
- Producing red blood cells
- Transporting oxygen to tissues
- Carrying white blood cells and draining tissue fluid (Correct answer)
- Producing hormones such as insulin
Correct answer: Carrying white blood cells and draining tissue fluid
The lymphatic system transports lymph, containing white blood cells (lymphocytes), and returns excess tissue fluid to the bloodstream.
Question 6: Which statement correctly describes the difference between type 1 and type 2 diabetes?
- Type 1 is treated with diet alone; type 2 requires insulin injections
- Type 1 occurs because the pancreas produces no insulin; type 2 involves insulin resistance (Correct answer)
- Type 2 is more severe and always requires insulin injections
- Type 1 is caused by overeating sugar; type 2 is an autoimmune condition
Correct answer: Type 1 occurs because the pancreas produces no insulin; type 2 involves insulin resistance
In type 1 diabetes, the immune system destroys insulin-producing beta cells; in type 2, body cells become resistant to insulin's effects.
Question 7: What is a monohybrid cross?
- A cross between two different species
- A cross examining the inheritance of two traits simultaneously
- A cross examining the inheritance of a single trait (Correct answer)
- A cross between organisms with identical genotypes
Correct answer: A cross examining the inheritance of a single trait
A monohybrid cross studies the inheritance pattern of a single characteristic, typically using a Punnett square to predict offspring ratios.
GCSE Biology 3
Which type of neuron carries impulses from the central nervous system to effectors such as muscles?