5/5/26, 9:01 AQA GCSE Biology Paper 2
AM
AQA GCSE Biology Paper 2
What is homeostasis? The maintenance of a constant internal
environment.
What is a stimulus? A change in your environment than requires a
response. e.g Light, sound, touch, pressure, pain,
chemical or temperature.
What do the receptors do? Detect the stimulus or change in environment.
What happens after the receptors? Receptors send messages to the CNS via the
sensory neurone.
What makes up the central nervous The brain or spinal cord
system?
What is an effector? Muscles or glands that bring about a response.
What do the muscles and glands do in Muscles contract and glands secrete chemical
response to stimuli? substances(hormones).
What is a sensory neurone? A neurone that carry information from the receptors
to the CNS.
What is a relay neurone? Neurones that carry impulses from the sensory
neurone to the motor neurone.
What is a motor neurone? Neurones that carry information from the CNS to
the effectors.
What is the nervous system? It is a system that allows you to react to your
surroundings.
How do signals travel across a The chemical or neurotransmitter diffuses across
synapse? 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? A gap between two neurones.
What is the thermoregulatory centre Near the hypothalamus, monitors the temperature
of the brain? of blood.
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,5/5/26, 9:01 AQA GCSE Biology Paper 2
AM
Describe the stages in a reflex arc. Stimulus->Receptor->sensory neurone->CNS (relay
neurone) -> motor neurone -> effector -> response
Name responses that reduce body Hairs lie flat, sweat and blood vessels get
temperature. wider(vasodilation)
What happens during vasodilation? The blood vessels supplying the skin dilate (widen).
This helps to transfer energy to
the environment.
Name responses that increase body Hairs stand up, no sweat, shivering and blood
temperature. vessels constrict(vasoconstriction)
What happens during The blood vessels supplying the skin constrict to
vasoconstriction? close off the skins blood supply.
What is the body's core temp? 37 degrees Celsius
What are hormones? Chemical messengers that travel in the blood to
target organs.
Compare and Contrast the Nervous is faster acting than the endocrine system.
endocrine (hormone) system and Hormones have longer lasting effects compared to
the nervous system. electrical impulses. Nerves act on a very specific
area whereas hormones act more general.
What does the thyroid gland do? Produces thyroxine which is involved in regulating
metabolism.
What do the adrenal glands do? Produce adrenaline which is used to prepare the
body for fight or flight.
What is the role of the pancreas? Produces glucagon and insulin which are involved in
regulating glucose levels in the blood.
Name the hormone that is released Insulin
if blood sugar is too high.
What does insulin do? It makes the liver convert glucose into glycogen.
This causes blood glucose levels to decrease.
Name the hormone that is released Glucagon
if blood sugar is too low.
What does glucagon do? HINT GLU-COSE-GONE It makes the liver convert glycogen to
glucose. This causes the blood glucose level
to increase.
2/26
, 5/5/26, 9:01 AQA GCSE Biology Paper 2
AM
What is type I diabetes? When the pancreas produces little or no insulin.
What is type II diabetes? When a person becomes resistant to their own
insulin. Being overweight can increase your
chances of type II diabetes.
How can type I diabetes be treated? Insulin injections, limiting intake of foods rich is
simple carbohydrates e.g. sugars and regular
exercise.
How can type II diabetes be treated? It can be controlled by eating a carbohydrate
controlled diet and getting regular exercise.
What is the role of the kidneys. Kidneys make urine by taking unwanted waste
products out of your blood. They are involved in
selective reabsorption.
Name three things that are re- Glucose, water and ions.
absorbed by the kidneys into the
blood.
Name three things that are removed Urea, water and ions.
from the body in the urine.
What is deamination? Proteins (excess amino acids) cannot be stored by
the body. Excess amino acids are converted to fats
and carbohydrates. This occurs in the liver.
What is produced as a waste product Ammonia is produced as a waste product. Ammonia
of deamination? is toxic so it is converted into urea in the liver.
What hormone controls the amount ADH
of water absorbed by the kidneys?
What happens when the concentration of water in the Receptors in the hypothalamus
detects the water content is too low. The coordinator blood is too low. I.e. the Blood is MORE
concentrated. in the brain receives the information and coordinates
a response. The pituitary
gland produces MORE (Anti-diuretic hormone) ADH,
which makes the kidney tubule MORE permeable.
This means that MORE water is reabsorbed into the
bloodstream. The kidneys produce a small volume of
concentrated urine.
What happens when the Receptors in the hypothalamus detects the water
concentration of water in the blood content is too high. The coordinator in the brain
is too high. I.e. the Blood is receives the information and coordinates a
dilute/LESS concentrated. response. The pituitary gland produced LESS ADH,
which makes the kidney tubule LESS permeable.
This means that LESS water is reabsorbed into the
bloodstream. The kidneys produce a large volume
of dilute urine.
3/26
AM
AQA GCSE Biology Paper 2
What is homeostasis? The maintenance of a constant internal
environment.
What is a stimulus? A change in your environment than requires a
response. e.g Light, sound, touch, pressure, pain,
chemical or temperature.
What do the receptors do? Detect the stimulus or change in environment.
What happens after the receptors? Receptors send messages to the CNS via the
sensory neurone.
What makes up the central nervous The brain or spinal cord
system?
What is an effector? Muscles or glands that bring about a response.
What do the muscles and glands do in Muscles contract and glands secrete chemical
response to stimuli? substances(hormones).
What is a sensory neurone? A neurone that carry information from the receptors
to the CNS.
What is a relay neurone? Neurones that carry impulses from the sensory
neurone to the motor neurone.
What is a motor neurone? Neurones that carry information from the CNS to
the effectors.
What is the nervous system? It is a system that allows you to react to your
surroundings.
How do signals travel across a The chemical or neurotransmitter diffuses across
synapse? 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? A gap between two neurones.
What is the thermoregulatory centre Near the hypothalamus, monitors the temperature
of the brain? of blood.
1/26
,5/5/26, 9:01 AQA GCSE Biology Paper 2
AM
Describe the stages in a reflex arc. Stimulus->Receptor->sensory neurone->CNS (relay
neurone) -> motor neurone -> effector -> response
Name responses that reduce body Hairs lie flat, sweat and blood vessels get
temperature. wider(vasodilation)
What happens during vasodilation? The blood vessels supplying the skin dilate (widen).
This helps to transfer energy to
the environment.
Name responses that increase body Hairs stand up, no sweat, shivering and blood
temperature. vessels constrict(vasoconstriction)
What happens during The blood vessels supplying the skin constrict to
vasoconstriction? close off the skins blood supply.
What is the body's core temp? 37 degrees Celsius
What are hormones? Chemical messengers that travel in the blood to
target organs.
Compare and Contrast the Nervous is faster acting than the endocrine system.
endocrine (hormone) system and Hormones have longer lasting effects compared to
the nervous system. electrical impulses. Nerves act on a very specific
area whereas hormones act more general.
What does the thyroid gland do? Produces thyroxine which is involved in regulating
metabolism.
What do the adrenal glands do? Produce adrenaline which is used to prepare the
body for fight or flight.
What is the role of the pancreas? Produces glucagon and insulin which are involved in
regulating glucose levels in the blood.
Name the hormone that is released Insulin
if blood sugar is too high.
What does insulin do? It makes the liver convert glucose into glycogen.
This causes blood glucose levels to decrease.
Name the hormone that is released Glucagon
if blood sugar is too low.
What does glucagon do? HINT GLU-COSE-GONE It makes the liver convert glycogen to
glucose. This causes the blood glucose level
to increase.
2/26
, 5/5/26, 9:01 AQA GCSE Biology Paper 2
AM
What is type I diabetes? When the pancreas produces little or no insulin.
What is type II diabetes? When a person becomes resistant to their own
insulin. Being overweight can increase your
chances of type II diabetes.
How can type I diabetes be treated? Insulin injections, limiting intake of foods rich is
simple carbohydrates e.g. sugars and regular
exercise.
How can type II diabetes be treated? It can be controlled by eating a carbohydrate
controlled diet and getting regular exercise.
What is the role of the kidneys. Kidneys make urine by taking unwanted waste
products out of your blood. They are involved in
selective reabsorption.
Name three things that are re- Glucose, water and ions.
absorbed by the kidneys into the
blood.
Name three things that are removed Urea, water and ions.
from the body in the urine.
What is deamination? Proteins (excess amino acids) cannot be stored by
the body. Excess amino acids are converted to fats
and carbohydrates. This occurs in the liver.
What is produced as a waste product Ammonia is produced as a waste product. Ammonia
of deamination? is toxic so it is converted into urea in the liver.
What hormone controls the amount ADH
of water absorbed by the kidneys?
What happens when the concentration of water in the Receptors in the hypothalamus
detects the water content is too low. The coordinator blood is too low. I.e. the Blood is MORE
concentrated. in the brain receives the information and coordinates
a response. The pituitary
gland produces MORE (Anti-diuretic hormone) ADH,
which makes the kidney tubule MORE permeable.
This means that MORE water is reabsorbed into the
bloodstream. The kidneys produce a small volume of
concentrated urine.
What happens when the Receptors in the hypothalamus detects the water
concentration of water in the blood content is too high. The coordinator in the brain
is too high. I.e. the Blood is receives the information and coordinates a
dilute/LESS concentrated. response. The pituitary gland produced LESS ADH,
which makes the kidney tubule LESS permeable.
This means that LESS water is reabsorbed into the
bloodstream. The kidneys produce a large volume
of dilute urine.
3/26
