What's the difference between communicable and non-communicable diseases?

Communicable diseases are caused by pathogens (like bacteria or viruses) and can be passed from person to person, e.g., flu, measles. Non-communicable diseases are not infectious and cannot be transmitted; they are often caused by lifestyle factors, genetics, or environmental factors, e.g., heart disease, cancer, diabetes.

How do vaccines work to prevent disease?

Vaccines contain a weakened or dead form of a pathogen, or just its antigens. When injected, they stimulate the immune system to produce antibodies and memory cells without causing the disease. If the real pathogen later enters the body, memory cells quickly trigger antibody production, preventing infection.

Why can't antibiotics cure the flu?

Antibiotics target bacteria by disrupting their cell walls or protein synthesis. The flu is caused by a virus, which has a different structure and replicates inside human cells. Antibiotics cannot enter human cells or target viral processes, so they are ineffective against viral infections.

What is antibiotic resistance and why is it a problem?

Antibiotic resistance occurs when bacteria evolve to survive exposure to antibiotics. This happens through natural selection: some bacteria have random mutations that make them resistant. When antibiotics kill non-resistant bacteria, the resistant ones survive and multiply. This makes infections harder to treat, leading to longer illnesses and more deaths.

How does smoking increase the risk of heart disease?

Smoking damages the lining of blood vessels, causing them to narrow and harden (atherosclerosis). It also increases blood pressure and makes blood more likely to clot. This reduces blood flow to the heart, increasing the risk of coronary heart disease and heart attacks.

What are the body's first lines of defence against pathogens?

The body has physical and chemical barriers. Physical barriers include skin (blocks entry), mucous membranes (trap pathogens), and cilia (sweep mucus away). Chemical barriers include stomach acid (kills bacteria), lysozyme in tears (breaks down bacterial cell walls), and antimicrobial proteins in skin.

Health and disease

WJEC

GCSE

This topic explores the relationship between health and disease, covering the causes of communicable and non-communicable diseases. It details human and plant defense mechanisms, the role of the immune system, the development of medicines, and the impact of lifestyle factors on health.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

Topic Overview

Health and disease is a core topic in WJEC GCSE Biology that explores the relationship between the human body and the factors that keep it healthy or cause illness. You'll learn about communicable diseases (caused by pathogens like bacteria and viruses) and non-communicable diseases (such as heart disease and cancer). The topic also covers how lifestyle choices, diet, and the immune system affect our health. Understanding this is crucial because it connects biology to real-world issues like public health, vaccination programmes, and the global impact of diseases.

This topic builds on your knowledge of cells, tissues, and organ systems. You'll investigate how pathogens enter the body, how they cause damage, and how the body defends itself through physical barriers (like skin) and the immune response (including white blood cells and antibodies). You'll also study the role of drugs in treating disease, including antibiotics and their limitations due to antibiotic resistance. By the end, you should be able to explain how diseases spread, how they can be prevented, and why lifestyle factors such as smoking, poor diet, and lack of exercise increase the risk of non-communicable diseases.

Health and disease is not just about memorising facts; it's about applying biological principles to everyday life. For example, you'll use your understanding of pathogens to explain why handwashing is important, or why antibiotics don't work against viruses. This topic also links to other areas of biology, such as genetics (inherited diseases) and ecology (how diseases spread in populations). Mastering it will give you a solid foundation for understanding more complex topics like the nervous system or homeostasis.

Key Concepts

Core ideas you must understand for this topic

→Pathogens are microorganisms (bacteria, viruses, fungi, protists) that cause communicable diseases. Bacteria reproduce rapidly and produce toxins; viruses invade host cells and replicate inside them.
→The immune system defends the body using white blood cells: phagocytes engulf pathogens, while lymphocytes produce antibodies and antitoxins. Memory cells provide long-term immunity after infection or vaccination.
→Non-communicable diseases (e.g., coronary heart disease, type 2 diabetes, cancer) are not infectious and are often linked to lifestyle factors like smoking, poor diet, lack of exercise, and excessive alcohol consumption.
→Antibiotics kill or inhibit bacteria but are ineffective against viruses. Overuse of antibiotics leads to antibiotic resistance, where bacteria evolve and survive treatment (e.g., MRSA).
→Vaccination involves introducing a weakened or dead pathogen to stimulate the immune system to produce memory cells, providing immunity without causing disease.

What You Need to Demonstrate

Key skills and knowledge for this topic

Distinction between communicable and non-communicable diseases
Mechanisms of pathogen spread (contact, aerosol, body fluids, water, insects, food)
Non-specific human defenses (skin, blood clots)
Immune system function (lymphocytes, antibodies, antitoxins, phagocytes)
Production and use of monoclonal antibodies
Plant physical and chemical defense responses
Vaccination principles and factors influencing parental decisions
Antibiotic function and the issue of antibiotic resistance (e.g., MRSA)

Marking Points

Key points examiners look for in your answers

Distinction between communicable and non-communicable diseases
Mechanisms of pathogen spread (contact, aerosol, body fluids, water, insects, food)
Non-specific human defenses (skin, blood clots)
Immune system function (lymphocytes, antibodies, antitoxins, phagocytes)
Production and use of monoclonal antibodies
Plant physical and chemical defense responses
Vaccination principles and factors influencing parental decisions
Antibiotic function and the issue of antibiotic resistance (e.g., MRSA)
Stages of drug development (preclinical and clinical testing)
Lifestyle factors affecting non-communicable diseases (exercise, diet, alcohol, smoking, UV)
Treatments for cardiovascular disease (statins, angioplasty, lifestyle changes)

Examiner Tips

Expert advice for maximising your marks

💡Use specific terminology for immune responses (e.g., antigen-specific antibodies)
💡When discussing drug development, ensure you mention both preclinical and clinical stages
💡Be prepared to evaluate the advantages and disadvantages of cardiovascular treatments
💡Link lifestyle factors directly to the incidence of specific non-communicable diseases
💡Apply aseptic techniques knowledge to the antibiotic investigation context
💡When explaining how the immune system fights a pathogen, always mention both phagocytes (engulfing) and lymphocytes (producing antibodies). Use specific terms like 'antigen', 'antibody', and 'memory cell' to show deeper understanding.
💡For questions on lifestyle and disease, link the risk factor to the biological mechanism. For example, smoking damages cilia in the airways, leading to increased mucus and risk of lung infections; it also narrows blood vessels, increasing blood pressure and risk of heart disease.
💡In questions about antibiotic resistance, explain that it occurs due to natural selection: bacteria with resistance genes survive and reproduce, passing on the resistance. Avoid saying bacteria 'learn' or 'adapt' – use the correct evolutionary language.

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing the roles of lymphocytes and phagocytes
Assuming antibiotics kill viruses
Failing to distinguish between physical and chemical plant defenses
Misunderstanding the 'balance of probability' nature of scientific evidence in vaccination debates
Inaccurate description of the stages of drug development
Misconception: Antibiotics can cure viral infections like the common cold. Correction: Antibiotics only work against bacteria, not viruses. Viral infections need to run their course or be treated with antiviral drugs (if available).
Misconception: All bacteria are harmful. Correction: Many bacteria are harmless or beneficial (e.g., gut bacteria help digestion). Only pathogenic bacteria cause disease.
Misconception: Vaccines cause the disease they protect against. Correction: Vaccines contain weakened or dead pathogens, or just antigens, so they cannot cause the full disease. They may cause mild symptoms but provide immunity.

Frequently Asked Questions

Common questions students ask about this topic

Before You Start

Prior knowledge that will help with this topic

•Cell structure and function (including bacteria and viruses as cells/non-cellular particles).
•Basic understanding of enzymes and proteins (for antibody function).
•Organ systems (especially the circulatory and respiratory systems) to understand how diseases affect the body.

Study Guide Available

Comprehensive revision notes & examples

Read Study Guide

Likely Command Words

How questions on this topic are typically asked

Describe

Explain

Discuss

Evaluate

Recall

Ready to test yourself?

Practice questions tailored to this topic

Health and disease

Topic Overview

Key Concepts

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Frequently Asked Questions

Before You Start

Study Guide Available

Likely Command Words

Ready to test yourself?

Related Topics in WJEC GCSE Biology

Biodiversity

Cell biology

Cell metabolism

Communicable disease

Topic Synopsis

Key Concepts & Core Principles

Exam Tips & Revision Strategies

Common Misconceptions & Mistakes to Avoid

Examiner Marking Points

Health and disease

Topic Overview

Key Concepts

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Frequently Asked Questions

What's the difference between communicable and non-communicable diseases?

How do vaccines work to prevent disease?

Why can't antibiotics cure the flu?

What is antibiotic resistance and why is it a problem?

How does smoking increase the risk of heart disease?

What are the body's first lines of defence against pathogens?

Before You Start

Study Guide Available

Likely Command Words

Ready to test yourself?

Related Topics in WJEC GCSE Biology

Biodiversity

Cell biology

Cell metabolism

Communicable disease