AQA GCSE Biology Paper 2 2024/2025
Exam All Answers and Illustrations
Given
What is homeostasis? - 🧠 ANSWER ✔✔The maintenance of a constant
internal environment.
What is a stimulus? - 🧠 ANSWER ✔✔A change in your environment than
requires a response. e.g Light, sound, touch, pressure, pain, chemical or
temperature.
What do the receptors do? - 🧠 ANSWER ✔✔Detect the stimulus or change
in environment.
What happens after the receptors? - 🧠 ANSWER ✔✔Receptors send
messages to the CNS via the sensory neurone.
What makes up the central nervous system? - 🧠 ANSWER ✔✔The brain or
spinal cord
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
1
STATEMENT. ALL RIGHTS RESERVED
,What is an effector? - 🧠 ANSWER ✔✔Muscles or glands that bring about a
response.
What do the muscles and glands do in response to stimuli? - 🧠 ANSWER
✔✔Muscles contract and glands secrete chemical substances(hormones).
What is a sensory neurone? - 🧠 ANSWER ✔✔A neurone that carry
information from the receptors to the CNS.
What is a relay neurone? - 🧠 ANSWER ✔✔Neurones that carry impulses
from the sensory neurone to the motor neurone.
What is a motor neurone? - 🧠 ANSWER ✔✔Neurones that carry
information from the CNS to the effectors.
What is the nervous system? - 🧠 ANSWER ✔✔It is a system that allows
you to react to your surroundings.
How do signals travel across a synapse? - 🧠 ANSWER ✔✔The chemical or
neurotransmitter diffuses across the synapse and binds to a
complementary receptor on the neurone (postsynaptic). This causes an
electrical impulse to travel down the next neurone.
What is a synapse? - 🧠 ANSWER ✔✔A gap between two neurones.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
2
STATEMENT. ALL RIGHTS RESERVED
,What is the thermoregulatory centre of the brain? - 🧠 ANSWER ✔✔Near
the hypothalamus, monitors the temperature of blood.
Describe the stages in a reflex arc. - 🧠 ANSWER ✔✔Stimulus->Receptor-
>sensory neurone->CNS (relay neurone) -> motor neurone -> effector ->
response
Name responses that reduce body temperature. - 🧠 ANSWER ✔✔Hairs lie
flat, sweat and blood vessels get wider(vasodilation)
What happens during vasodilation? - 🧠 ANSWER ✔✔The blood vessels
supplying the skin dilate (widen). This helps to transfer energy to the
environment.
Name responses that increase body temperature. - 🧠 ANSWER ✔✔Hairs
stand up, no sweat, shivering and blood vessels constrict(vasoconstriction)
What happens during vasoconstriction? - 🧠 ANSWER ✔✔The blood
vessels supplying the skin constrict to close off the skins blood supply.
What is the body's core temp? - 🧠 ANSWER ✔✔37 degrees Celsius
What are hormones? - 🧠 ANSWER ✔✔Chemical messengers that travel in
the blood to target organs.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
3
STATEMENT. ALL RIGHTS RESERVED
, Compare and Contrast the endocrine (hormone) system and the nervous
system. - 🧠 ANSWER ✔✔Nervous is faster acting than the endocrine
system.
Hormones have longer lasting effects compared to electrical impulses.
Nerves act on a very specific area whereas hormones act more general.
What does the thyroid gland do? - 🧠 ANSWER ✔✔Produces thyroxine
which is involved in regulating metabolism.
What do the adrenal glands do? - 🧠 ANSWER ✔✔Produce adrenaline
which is used to prepare the body for fight or flight.
What is the role of the pancreas? - 🧠 ANSWER ✔✔Produces glucagon and
insulin which are involved in regulating glucose levels in the blood.
Name the hormone that is released if blood sugar is too high. - 🧠 ANSWER
✔✔Insulin
What does insulin do? - 🧠 ANSWER ✔✔It makes the liver convert glucose
into glycogen. This causes blood glucose levels to decrease.
Name the hormone that is released if blood sugar is too low. - 🧠 ANSWER
✔✔Glucagon
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
4
STATEMENT. ALL RIGHTS RESERVED
Exam All Answers and Illustrations
Given
What is homeostasis? - 🧠 ANSWER ✔✔The maintenance of a constant
internal environment.
What is a stimulus? - 🧠 ANSWER ✔✔A change in your environment than
requires a response. e.g Light, sound, touch, pressure, pain, chemical or
temperature.
What do the receptors do? - 🧠 ANSWER ✔✔Detect the stimulus or change
in environment.
What happens after the receptors? - 🧠 ANSWER ✔✔Receptors send
messages to the CNS via the sensory neurone.
What makes up the central nervous system? - 🧠 ANSWER ✔✔The brain or
spinal cord
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
1
STATEMENT. ALL RIGHTS RESERVED
,What is an effector? - 🧠 ANSWER ✔✔Muscles or glands that bring about a
response.
What do the muscles and glands do in response to stimuli? - 🧠 ANSWER
✔✔Muscles contract and glands secrete chemical substances(hormones).
What is a sensory neurone? - 🧠 ANSWER ✔✔A neurone that carry
information from the receptors to the CNS.
What is a relay neurone? - 🧠 ANSWER ✔✔Neurones that carry impulses
from the sensory neurone to the motor neurone.
What is a motor neurone? - 🧠 ANSWER ✔✔Neurones that carry
information from the CNS to the effectors.
What is the nervous system? - 🧠 ANSWER ✔✔It is a system that allows
you to react to your surroundings.
How do signals travel across a synapse? - 🧠 ANSWER ✔✔The chemical or
neurotransmitter diffuses across the synapse and binds to a
complementary receptor on the neurone (postsynaptic). This causes an
electrical impulse to travel down the next neurone.
What is a synapse? - 🧠 ANSWER ✔✔A gap between two neurones.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
2
STATEMENT. ALL RIGHTS RESERVED
,What is the thermoregulatory centre of the brain? - 🧠 ANSWER ✔✔Near
the hypothalamus, monitors the temperature of blood.
Describe the stages in a reflex arc. - 🧠 ANSWER ✔✔Stimulus->Receptor-
>sensory neurone->CNS (relay neurone) -> motor neurone -> effector ->
response
Name responses that reduce body temperature. - 🧠 ANSWER ✔✔Hairs lie
flat, sweat and blood vessels get wider(vasodilation)
What happens during vasodilation? - 🧠 ANSWER ✔✔The blood vessels
supplying the skin dilate (widen). This helps to transfer energy to the
environment.
Name responses that increase body temperature. - 🧠 ANSWER ✔✔Hairs
stand up, no sweat, shivering and blood vessels constrict(vasoconstriction)
What happens during vasoconstriction? - 🧠 ANSWER ✔✔The blood
vessels supplying the skin constrict to close off the skins blood supply.
What is the body's core temp? - 🧠 ANSWER ✔✔37 degrees Celsius
What are hormones? - 🧠 ANSWER ✔✔Chemical messengers that travel in
the blood to target organs.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
3
STATEMENT. ALL RIGHTS RESERVED
, Compare and Contrast the endocrine (hormone) system and the nervous
system. - 🧠 ANSWER ✔✔Nervous is faster acting than the endocrine
system.
Hormones have longer lasting effects compared to electrical impulses.
Nerves act on a very specific area whereas hormones act more general.
What does the thyroid gland do? - 🧠 ANSWER ✔✔Produces thyroxine
which is involved in regulating metabolism.
What do the adrenal glands do? - 🧠 ANSWER ✔✔Produce adrenaline
which is used to prepare the body for fight or flight.
What is the role of the pancreas? - 🧠 ANSWER ✔✔Produces glucagon and
insulin which are involved in regulating glucose levels in the blood.
Name the hormone that is released if blood sugar is too high. - 🧠 ANSWER
✔✔Insulin
What does insulin do? - 🧠 ANSWER ✔✔It makes the liver convert glucose
into glycogen. This causes blood glucose levels to decrease.
Name the hormone that is released if blood sugar is too low. - 🧠 ANSWER
✔✔Glucagon
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
4
STATEMENT. ALL RIGHTS RESERVED
