Give an ethical reason why a healthy person's brain is never deliberately damaged in an experiment.

It would cause permanent harm to someone who is well, which can never be justified by the knowledge gained.

How is an MRI scanner used to study brain function?

It produces a detailed image of the structure of the brain and can show which regions become more active while a person carries out a task.

Give one limitation of using scans to work out what a region of the brain does.

A scan shows only that a region is active, not what it is doing, and activity does not prove that region causes the behaviour being studied.

OCR GCSE Biology A J247

Cell Level Systems

Topic overview Microscopy, and sub-cellular structures DNA structure: polymer, double helix and nucleotides Protein synthesis and the triplet code Enzyme action, and investigating enzymes Cellular respiration as an exothermic process Aerobic and anaerobic respiration compared Synthesis and breakdown of carbohydrates, proteins and lipids Photosynthesis: producers and the process Photosynthesis as endothermic, and investigating it Limiting factors in photosynthesis

Community Level Systems

Topic overview Cycling materials, and the role of microorganisms The carbon and water cycles, and decomposition Levels of organisation, and abiotic and biotic factors Interdependence, competition and trophic levels Pyramids of biomass and the efficiency of transfer

Genes, Inheritance and Selection

Topic overview Genetic terms, and the genome Genome, environment and mutations How genetic variants influence phenotype Asexual and sexual reproduction compared Haploid, diploid and meiosis Single gene inheritance and Punnett squares Sex determination, multiple genes and Mendel's work Variation within a population, and classification Natural selection and evolution Evidence for evolution, and the work of Darwin and Wallace

Global Challenges

Topic overview Field investigations, and human impact on ecosystems Maintaining biodiversity, and evidence for environmental change Food security, agricultural and biotechnological solutions Selective breeding and genetic engineering Health, disease, and types of disease Interactions between diseases, and how they spread Reducing the spread of disease, and named examples Physical and chemical plant defences Detecting plant disease; white blood cells and platelets Non-specific defences and the immune system Monoclonal antibodies and their uses Vaccines, medicines and aseptic technique Developing new medicines, and non-communicable disease Treating cardiovascular disease, and lifestyle factors Cancer, and the use of stem cells in medicine Gene technology in medicine, and the human genome

Organism Level Systems

Topic overview The nervous system and coordinated responses The reflex arc The eye and its common defects The structure and function of the brain Investigating and treating the brain Hormonal coordination, thyroxine and adrenaline Hormones in reproduction and the menstrual cycle Contraception and treating infertility Plant hormones and their commercial uses Homeostasis, and the skin in temperature control Insulin and glucagon in blood sugar control Type 1 and type 2 diabetes Osmotic changes in body fluids, and the kidneys The kidney tubule and the effect of ADH Responding to temperature and osmotic challenges

Scaling Up

Topic overview Diffusion, osmosis and active transport Mitosis, the cell cycle and cell differentiation Stem cells in animals and meristems in plants Surface area to volume ratio and exchange surfaces The circulatory system, the heart and blood vessels Red blood cells and plasma Root hair cells, transpiration and translocation Xylem and phloem Factors affecting water uptake, and the potometer

Organism Level Systems

Investigating and treating the brain

3 things to know
Paper 3

Overview

Why brain damage case studies are scarce and hard to interpret, consent and ethics, MRI scans and their limits, animal and surgical studies, and why brain and spinal injuries and tumours are hard to treat.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Why is it hard to collect enough case studies of people with damage to one region of the brain?

Key term

Why are the results from a patient with brain damage difficult to interpret?

Key term

Why can consent be a difficulty when studying a patient with severe brain damage?

Questions from this subtopic

Each one with the model answer underneath.

1
Why is it hard to collect enough case studies of people with damage to one region of the brain?
Model answer
Injury to a single named region is rare, so very few patients with comparable damage are ever available to study.
2
Why are the results from a patient with brain damage difficult to interpret?
Model answer
The damage is rarely confined to one region and every injury and recovery is different, so a conclusion from one patient cannot safely be applied to everyone.
3
Give an ethical reason why a healthy person's brain is never deliberately damaged in an experiment.
Model answer
It would cause permanent harm to someone who is well, which can never be justified by the knowledge gained.
4
Why can consent be a difficulty when studying a patient with severe brain damage?
Model answer
The damage may leave the patient unable to understand what is being asked or unable to communicate a decision.
5
How is an MRI scanner used to study brain function?
Model answer
It produces a detailed image of the structure of the brain and can show which regions become more active while a person carries out a task.
6
Give one limitation of using scans to work out what a region of the brain does.
Model answer
A scan shows only that a region is active, not what it is doing, and activity does not prove that region causes the behaviour being studied.

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Cell Level Systems

Community Level Systems

Genes, Inheritance and Selection

Global Challenges

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