AQA AS BIOLOGY UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS FULL
SOLUTION
●● 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.
QUESTIONS AND CORRECT ANSWERS FULL
SOLUTION
●● 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.
