AQA AS BIOLOGY PAPER 2
PRACTICE SOLUTION STUDY
PAPER GUARANTEED TO PASS
2026
• homeostasis. Answer: A tendency to maintain a balanced or constant
internal state; the regulation of any aspect of body chemistry, such as
blood glucose, around a particular level
• nervous system. Answer: A conglomeration of billions of cells
specifically designed to provide a communication network within the
human body.
• receptors. Answer: Special structures that allow living organisms to
sense the conditions of their internal or external environment
• stimuli. Answer: Changes, occurring within or outside the body, that
affect nervous system functioning.
• coordination centres. Answer: receive and process info from receptors
• effectors. Answer: muscles or glands that carry out the correct response
to stimuli
,• nerve. Answer: A cordlike bundle of neuronal axons and/or dendrites
and associated connective tissue coursing together outside the central
nervous system
• central nervous system. Answer: The brain and spinal cord; CNS
• sensory neurones. Answer: nerve cells that carry messages from cells
in the sense organs to the CNS
• motor neurones. Answer: Nerve cells that carry messages from the
CNS to effectors
• gland. Answer: An organ that produces and releases chemicals either
through ducts or into the bloodstream.
• reflex. Answer: A simple, automatic response to a sensory stimulus,
such as the knee-jerk response. Automatic and rapid; they do not involve
the conscious part of the brain.
• reflex arc. Answer: nerve pathway in which an impulse crosses only
two synapses before producing a response; stimulus - receptor - sensory
neurone - relay neurone - motor neurone - effector - response
• neurotransmitters. Answer: Chemical messengers that cross the
synaptic gaps between neurons.
,• relay neurones. Answer: Nerve cells that carry signals from sensory
neurones to motor neurones
• cerebral cortex. Answer: The part of the brain where information
processing takes place. Divided into four lobes.
• medulla. Answer: The base of the brainstem; controls heartbeat and
breathing.
• hypothalamus. Answer: A neural structure lying below the thalamus; it
directs several maintenance activities (eating, drinking, body
temperature), helps govern the endocrine system via the pituitary gland,
and is linked to emotion and reward.
• pituitary gland. Answer: The endocrine system's most influential gland.
Under the influence of the hypothalamus, it regulates growth and
controls other endocrine glands.
• cerebellum. Answer: A large structure of the hindbrain that controls
fine motor skills.
• accommodation. Answer: The process by which the eye's lens changes
shape to focus near or far objects on the retina.
• iris. Answer: A ring of muscle tissue that forms the colored portion of
the eye around the pupil and controls the size of the pupil opening.
, • pupil. Answer: The adjustable opening in the center of the eye through
which light enters.
• cornea. Answer: Clear membrane at the front of the globe covering the
iris, pupil, and anterior chamber. Responsible for 60% of the eye's
focusing power.
• lens. Answer: The transparent structure behind the pupil that changes
shape to help focus images on the retina.
• retina. Answer: The light-sensitive inner surface of the eye, containing
the receptor rods and cones plus layers of neurons that begin the
processing of visual information.
• sclera. Answer: Dense fibrous opaque outer coat enclosing the eyeball
except the part covered by the cornea; The "white" of the eye
• ciliary muscle. Answer: muscle that alters the shape of lens to
accommodate vision
• suspensory ligament. Answer: A series of fibres that hold the lens of
the eye in place
• optic nerve. Answer: the nerve that carries neural impulses from the
eye to the brain
PRACTICE SOLUTION STUDY
PAPER GUARANTEED TO PASS
2026
• homeostasis. Answer: A tendency to maintain a balanced or constant
internal state; the regulation of any aspect of body chemistry, such as
blood glucose, around a particular level
• nervous system. Answer: A conglomeration of billions of cells
specifically designed to provide a communication network within the
human body.
• receptors. Answer: Special structures that allow living organisms to
sense the conditions of their internal or external environment
• stimuli. Answer: Changes, occurring within or outside the body, that
affect nervous system functioning.
• coordination centres. Answer: receive and process info from receptors
• effectors. Answer: muscles or glands that carry out the correct response
to stimuli
,• nerve. Answer: A cordlike bundle of neuronal axons and/or dendrites
and associated connective tissue coursing together outside the central
nervous system
• central nervous system. Answer: The brain and spinal cord; CNS
• sensory neurones. Answer: nerve cells that carry messages from cells
in the sense organs to the CNS
• motor neurones. Answer: Nerve cells that carry messages from the
CNS to effectors
• gland. Answer: An organ that produces and releases chemicals either
through ducts or into the bloodstream.
• reflex. Answer: A simple, automatic response to a sensory stimulus,
such as the knee-jerk response. Automatic and rapid; they do not involve
the conscious part of the brain.
• reflex arc. Answer: nerve pathway in which an impulse crosses only
two synapses before producing a response; stimulus - receptor - sensory
neurone - relay neurone - motor neurone - effector - response
• neurotransmitters. Answer: Chemical messengers that cross the
synaptic gaps between neurons.
,• relay neurones. Answer: Nerve cells that carry signals from sensory
neurones to motor neurones
• cerebral cortex. Answer: The part of the brain where information
processing takes place. Divided into four lobes.
• medulla. Answer: The base of the brainstem; controls heartbeat and
breathing.
• hypothalamus. Answer: A neural structure lying below the thalamus; it
directs several maintenance activities (eating, drinking, body
temperature), helps govern the endocrine system via the pituitary gland,
and is linked to emotion and reward.
• pituitary gland. Answer: The endocrine system's most influential gland.
Under the influence of the hypothalamus, it regulates growth and
controls other endocrine glands.
• cerebellum. Answer: A large structure of the hindbrain that controls
fine motor skills.
• accommodation. Answer: The process by which the eye's lens changes
shape to focus near or far objects on the retina.
• iris. Answer: A ring of muscle tissue that forms the colored portion of
the eye around the pupil and controls the size of the pupil opening.
, • pupil. Answer: The adjustable opening in the center of the eye through
which light enters.
• cornea. Answer: Clear membrane at the front of the globe covering the
iris, pupil, and anterior chamber. Responsible for 60% of the eye's
focusing power.
• lens. Answer: The transparent structure behind the pupil that changes
shape to help focus images on the retina.
• retina. Answer: The light-sensitive inner surface of the eye, containing
the receptor rods and cones plus layers of neurons that begin the
processing of visual information.
• sclera. Answer: Dense fibrous opaque outer coat enclosing the eyeball
except the part covered by the cornea; The "white" of the eye
• ciliary muscle. Answer: muscle that alters the shape of lens to
accommodate vision
• suspensory ligament. Answer: A series of fibres that hold the lens of
the eye in place
• optic nerve. Answer: the nerve that carries neural impulses from the
eye to the brain
