Where did many of the earliest medicines originally come from? Give two examples.

From plants and microorganisms, such as aspirin from willow bark and penicillin from a mould.

What three things must a possible new medicine be tested for before it can be used?

Whether it is toxic, whether it actually works against the illness, and what dose is the most effective.

Describe what happens during preclinical testing of a new medicine.

The substance is tested in the laboratory on cells and tissues, and then on live animals, to look for toxic effects and to see whether it has the intended effect.

What happens in the later stages of clinical testing, once a medicine is known to be safe?

It is given to patients who have the illness, and different doses are compared to find the one that is most effective.

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

Global Challenges

Developing new medicines, and non-communicable disease

3 things to know
Paper 4

Overview

Where early medicines came from, testing new medicines for toxicity, efficacy and dose in preclinical and clinical trials, placebos and double-blind trials, why development is slow and costly, the interacting causes and risk factors of non-communicable diseases such as coronary heart disease, bronchitis, cirrhosis, type 2 diabetes and cancer, and peer review and how trial results are published and communicated.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Explain why type 2 diabetes is linked to diet.

Process

Describe the first stage of testing a new medicine on people.

Key term

What is a placebo, and why is one used in a trial?

Questions from this subtopic

Each one with the model answer underneath.

1
Where did many of the earliest medicines originally come from? Give two examples.
Model answer
From plants and microorganisms, such as aspirin from willow bark and penicillin from a mould.
2
What three things must a possible new medicine be tested for before it can be used?
Model answer
Whether it is toxic, whether it actually works against the illness, and what dose is the most effective.
3
Describe what happens during preclinical testing of a new medicine.
Model answer
The substance is tested in the laboratory on cells and tissues, and then on live animals, to look for toxic effects and to see whether it has the intended effect.
4
Describe the first stage of testing a new medicine on people.
Model answer
A very low dose is given to a small number of healthy volunteers, to check that it is safe and to record any side effects.
5
What happens in the later stages of clinical testing, once a medicine is known to be safe?
Model answer
It is given to patients who have the illness, and different doses are compared to find the one that is most effective.
6
What is a placebo, and why is one used in a trial?
Model answer
A dummy treatment containing no active substance; comparing it with the real medicine shows whether any improvement is caused by the medicine itself.

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Cell Level Systems

Community Level Systems

Genes, Inheritance and Selection

Global Challenges

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Algae and .

phytoplanktonfungianimals

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AThe blood becomes too dilute.

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Egestion means passing out of undigested food as faeces.

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