GCSE Biology 4 — Questions and Answers
Question 1: Which structure in the kidney is responsible for the filtration of blood?
- Loop of Henle
- Collecting duct
- Glomerulus (Correct answer)
- Ureter
Correct answer: Glomerulus
The glomerulus is a network of capillaries in the Bowman's capsule where high pressure forces small molecules out of the blood in ultrafiltration.
Question 2: What is the purpose of the acrosome in a sperm cell?
- To provide energy for swimming via respiration
- To contain the genetic material of the sperm
- To release enzymes that digest the egg's outer layer (Correct answer)
- To increase surface area for nutrient absorption
Correct answer: To release enzymes that digest the egg's outer layer
The acrosome at the sperm head's tip contains hydrolytic enzymes that digest the zona pellucida of the egg, enabling fertilisation.
Question 3: Which gas is produced as a waste product of anaerobic respiration in yeast?
- Oxygen
- Carbon dioxide (Correct answer)
- Nitrogen
- Water vapour
Correct answer: Carbon dioxide
During anaerobic respiration (fermentation), yeast converts glucose into ethanol and carbon dioxide in the absence of oxygen.
Question 4: What does the term 'biodiversity' refer to?
- The total mass of living organisms in an ecosystem
- The variety of different species and genetic variation within an ecosystem (Correct answer)
- The rate at which new species evolve over time
- The number of producers present in a food chain
Correct answer: The variety of different species and genetic variation within an ecosystem
Biodiversity encompasses the variety of species (species diversity) and genetic variation within species in a given area or ecosystem.
Question 5: Which hormone is produced by the pancreas to lower blood glucose concentration?
- Glucagon
- Adrenaline
- Insulin (Correct answer)
- Thyroxine
Correct answer: Insulin
Insulin is released by beta cells in the islets of Langerhans when blood glucose rises, stimulating cells to absorb glucose and converting it to glycogen.
Question 6: What is the adaptive advantage of a root hair cell having a large surface area?
- It allows the cell to carry out photosynthesis more efficiently
- It increases the rate of water and mineral ion absorption from the soil (Correct answer)
- It enables faster transport of glucose to the shoot
- It provides structural support to the plant root
Correct answer: It increases the rate of water and mineral ion absorption from the soil
Root hair cells extend into soil particles, greatly increasing the surface area available for osmosis (water) and active transport (minerals).
Question 7: In a reflex arc, what is the correct order of components involved in a reflex action?
- Effector → motor neuron → relay neuron → sensory neuron → receptor
- Receptor → sensory neuron → relay neuron → motor neuron → effector (Correct answer)
- Receptor → motor neuron → relay neuron → sensory neuron → effector
- Brain → relay neuron → motor neuron → sensory neuron → effector
Correct answer: Receptor → sensory neuron → relay neuron → motor neuron → effector
A reflex arc proceeds from receptor detection to sensory neuron, through a relay neuron in the spinal cord, then a motor neuron, and finally to the effector.
GCSE Biology 4
Which structure in the kidney is responsible for the filtration of blood?