Grey Matter | Edexcel A-Level Biology A (Salters-Nuffield) (9BN0)

Grey Matter

240 questions
17 subtopics
Topics 7 and 8, examined on Paper 2 and Paper 3
Paper 2 and Paper 3

Covers how information is carried and processed: the neurone and the action potential, the synapse, how the eye detects light, plant responses, the regions of the brain and how they are imaged, learning and its critical periods, and the drugs that act on the brain..

It covers the structure of neurones and myelination, the action potential and saltatory conduction, the structure of a synapse and calcium entry, neurotransmitter release and acetylcholine, rod cells and the detection of light, effectors, the neuromuscular junction and the pupil reflex, phytochrome and the response to light, iAA, phototropism and gravitropism, nervous against hormonal coordination, the regions of the brain and their functions, brain imaging: MRI, fMRI, PET and CT, critical periods and the Hubel and Wiesel experiments, nature, nurture, habituation and research ethics, dopamine, serotonin and their imbalance, l-Dopa and MDMA, genome sequencing, personalised medicine and its ethics and genetically modified organisms: benefits and risks.

Sample questions from Grey Matter

Answer each one closed book first, then open the answer.

The structure of neurones and myelination

What structural features of relay neurones allow them to integrate signals from multiple sources?

Show the answer
They have short axons and numerous dendrites.
The structure of a synapse and calcium entry

What is the synaptic cleft?

Show the answer
The narrow gap between the presynaptic and postsynaptic membranes.
Rod cells and the detection of light

What is the membrane potential of a rod cell in darkness, and why?

Show the answer
Around −40mV; the influx of sodium ions keeps the rod cell depolarised.
Phytochrome and the response to light

What happens to Pr when it absorbs red light?

Show the answer
Pr is converted to Pfr
Nervous against hormonal coordination

How long do the effects of nervous system responses typically last?

Show the answer
Short-duration effects.
Brain imaging: MRI, fMRI, PET and CT

What is injected into a patient before a PET scan?

Show the answer
A radioactive tracer, often glucose-based.
Nature, nurture, habituation and research ethics

Where does habituation occur in the nervous system, and how does this differ from sensory adaptation?

Show the answer
Habituation occurs in the central nervous system, whereas sensory adaptation occurs in sensory receptors. In habituation, the animal can still detect the stimulus.
L-Dopa and MDMA

Explain how L-Dopa alleviates the symptoms of Parkinson's disease at the synaptic level.

Show the answer
L-Dopa increases dopamine levels at synapses, compensating for the dopamine deficiency characteristic of Parkinson's disease.

The 17 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
The structure of neurones and myelination	Recall questions on sensory, relay and motor neurones, Schwann cells and the myelin sheath, and the nodes of Ranvier.	12
The action potential and saltatory conduction	Recall questions on the resting potential, depolarisation and repolarisation, the refractory period, and why myelination speeds conduction.	18
The structure of a synapse and calcium entry	Recall questions on the presynaptic and postsynaptic neurones, the cleft, vesicles, and what calcium entry triggers.	11
Neurotransmitter release and acetylcholine	Recall questions on how neurotransmitter crosses the cleft and binds, the role of acetylcholinesterase, and why transmission is one way.	11
Rod cells and the detection of light	Recall questions on rhodopsin and its two components, bleaching, and how hyperpolarisation of a rod cell signals to the bipolar neurone.	16
Effectors, the neuromuscular junction and the pupil reflex	Recall questions on what happens at a neuromuscular junction, antagonistic muscles of the iris, and the autonomic control of the pupil.	13
Phytochrome and the response to light	Recall questions on the Pr and Pfr forms, which is active, and how Pfr changes transcription in the nucleus.	10
IAA, phototropism and gravitropism	Recall questions on how IAA promotes cell elongation, how it redistributes in a shoot and a root, and why shoots and roots respond differently.	16
Nervous against hormonal coordination	Recall questions on the speed, duration and specificity of each system, and on how target cells respond to particular hormones.	10
The regions of the brain and their functions	Recall questions on the cerebral hemispheres, hypothalamus, cerebellum and medulla oblongata and what each controls.	20
Brain imaging: MRI, fMRI, PET and CT	Recall questions on what each technique measures, which show structure and which show function, and which involve ionising radiation.	19
Critical periods and the Hubel and Wiesel experiments	Recall questions on what a critical period is, the visual cortex, and what Hubel and Wiesel's work showed.	15
Nature, nurture, habituation and research ethics	Recall questions on twin, cross-cultural and animal studies, habituation and Core Practical 18, and the three Rs.	15
Dopamine, serotonin and their imbalance	Recall questions on what each neurotransmitter does and the conditions linked to too little of each.	12
L-Dopa and MDMA	Recall questions on why L-Dopa is given rather than dopamine, and on how MDMA affects serotonin release and reuptake.	12
Genome sequencing, personalised medicine and its ethics	Recall questions on what sequencing data allows, and on privacy, consent, ownership and access by insurers and employers.	9
Genetically modified organisms: benefits and risks	Recall questions on pharming and GM crops, and on gene flow, biodiversity, pest resistance and the economic risks to farmers.	21

Grey Matter is 240 of the 1,892 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.