What is gene therapy?

Treating an inherited disorder by putting a working copy of the faulty gene into the patient's cells.

Explain how gene therapy could help someone with cystic fibrosis.

Working copies of the gene are delivered into the cells lining the airways so they make the correct protein and the mucus produced is less thick.

Give two practical difficulties that have limited the success of gene therapy.

It is hard to get the gene into enough of the right cells, and the effect wears off as treated cells die and are replaced by untreated ones.

Give one benefit to a patient of being tested for a faulty allele.

A condition they are at risk of can be watched for and treated early, and they can make informed decisions about their health and family.

OCR GCSE Biology A J247

Cell Level Systems

Topic overview Microscopy, and sub-cellular structures DNA structure: polymer, double helix and nucleotides 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 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, monitoring conservation and ecotourism 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 White blood cells, antibodies and platelets Non-specific defences and the immune system 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 Hormones and the endocrine glands Hormones in reproduction and the menstrual cycle Methods of contraception Tropisms, auxin and the roles of plant hormones Homeostasis, and the skin in temperature control Insulin and the control of blood glucose Type 1 and type 2 diabetes Osmotic changes in body fluids, and the kidneys Kidney structure and the parts of the tubule

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

Gene technology in medicine, and the human genome

3 things to know
Paper 2

Overview

Insulin made by gene technology, gene therapy for disorders such as cystic fibrosis with its practical difficulties and risks, the benefits and the ethical and privacy concerns of genetic testing and changing embryos, sequencing the human genome, and how it helps predict disease risk, target drugs to a patient's genome, trace inherited disorders and develop new medicines.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Give one medicine already produced using gene technology, and explain how it is made.

Key term

Explain a risk of using a virus to carry a gene into a patient's cells.

Key term

Give one ethical objection to changing the genes of a human embryo.

Questions from this subtopic

Each one with the model answer underneath.

1
Give one medicine already produced using gene technology, and explain how it is made.
Model answer
Insulin is made by bacteria that have been given the human insulin gene and are then grown in large numbers in fermenters.
2
What is gene therapy?
Model answer
Treating an inherited disorder by putting a working copy of the faulty gene into the patient's cells.
3
Explain how gene therapy could help someone with cystic fibrosis.
Model answer
Working copies of the gene are delivered into the cells lining the airways so they make the correct protein and the mucus produced is less thick.
4
Give two practical difficulties that have limited the success of gene therapy.
Model answer
It is hard to get the gene into enough of the right cells, and the effect wears off as treated cells die and are replaced by untreated ones.
5
Explain a risk of using a virus to carry a gene into a patient's cells.
Model answer
The virus may trigger a damaging immune reaction, or the gene may insert itself where it disrupts another gene and causes cancer.
6
Give one benefit to a patient of being tested for a faulty allele.
Model answer
A condition they are at risk of can be watched for and treated early, and they can make informed decisions about their health and family.

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Cell Level Systems

Community Level Systems

Genes, Inheritance and Selection

Global Challenges

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Algae and .

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AA diet high in sugar and fat leads to obesity.

BBody cells then respond poorly to insulin.

CBlood glucose concentration cannot be controlled.

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Egestion means passing out of undigested food as faeces.

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