Aqa Gcse Biology Higher Tier Paper 1H Exam Prep Study Guide 2025 Questions And Answers Fully Solved

AQA GCSE BIOLOGY HIGHER TIER PAPER 1H
EXAM PREP STUDY GUIDE 2025 QUESTIONS
AND ANSWERS FULLY SOLVED
◉ 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


◉ 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.


◉ 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.


◉ 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


◉ What does glucagon do? HINT GLU-COSE-GONE Answer: It makes
the liver convert glycogen to glucose. This causes the blood glucose
level to increase.