Topic 5: Health, Disease and the Development of Medicines

Contents Overview

• Definitions of Health, Disease, and Susceptibility
• Pathogens and Common Infections
• Pathogen Spread and Disease Prevention
• Biology Only: Lifecycle of a Virus, Plant Barriers, Aseptic Techniques, etc.
• Human Barriers and The Immune Response
• Immunisation and Antibiotics
• Developing New Medicines
• Higher and Biology Only: Monoclonal Antibodies
• Factors Affecting Non-Communicable Diseases
• Evaluating Treatments for Cardiovascular Disease

Key Definitions

• Health: Complete physical, mental, and social well-being (WHO).
• Disease: Communicable vs. Non-communicable.
  • Communicable: Can be transferred (e.g., flu, common cold).
  • Non-Communicable: Not transferable (e.g., cardiovascular disease, asthma).
• Susceptibility: Presence of one disease can increase risk to others (e.g., HIV).

Pathogens (5.4)

• Viruses: Use host cells to replicate, causing cell damage.
• Bacteria: Multiply quickly, produce toxins.
• Fungi: Produce spores, cause infections.
• Protists: Parasitic, damage hosts.

Common Infections (5.5)

• Cholera (Bacteria): Spread via water.
• Tuberculosis (Bacteria): Airborne.
• Malaria (Protists): Spread by mosquitoes.
• HIV (Virus): Spread through body fluids.
• Ebola (Virus): Spread through body fluids.

Pathogen Spread (5.6)

• Direct contact, water, air.
• Prevention by hygiene, reducing contact, vaccination.

Biology Only: Lifecycle of a Virus (5.7B)

• Lytic Pathway: Replication in host, cell bursts.
• Lysogenic Pathway: Virus incorporates into host DNA.

Sexually Transmitted Infections (5.8)

• Spread through sexual contact.
• Prevention by using barrier methods.

Plant Barriers (5.9B, 5.10B)

• Physical Barriers: Cell wall, waxy cuticle, bark.
• Chemical Barriers: Antimicrobial chemicals.

Human Barriers (5.12)

• Physical: Mucus, Cilia, Skin
• Chemical: Lysozymes, Hydrochloric acid.

Immune Response (5.13)

• Phagocytosis: Engulfing pathogens.
• Antibodies: Bind to antigens, aid in pathogen destruction.
• Memory Lymphocytes: Provide immunity by remembering pathogens.

Immunisation (5.14, 5.15B)

• Simulates infection to provide immunity.
• Advantages: Eradicates diseases, herd immunity.
• Disadvantages: Not always effective, rare adverse reactions.

Antibiotics (5.16)

• Treat bacterial infections, not effective against viruses.

Aseptic Techniques (5.17B)

• Culturing Microorganisms: Nutrient broth, agar plates.
• Importance of sterilization to prevent contamination.

Developing New Medicines (5.20)

• Initially discovered in plants/microorganisms.
• Testing: Preclinical (cells, animals), clinical trials (volunteers).

Higher and Biology Only: Monoclonal Antibodies (5.21B, 5.22B)

• Production: Hybridomas from mice lymphocytes.
• Uses: Pregnancy tests, disease treatment, research.
• Advantages/Disadvantages: Specific targeting but costly to develop.

Non-Communicable Diseases (5.23, 5.24)

• Influenced by lifestyle and genetic factors.
• Examples: Cardiovascular disease, cancers, obesity, malnutrition.
• Prevention: Healthy diet and exercise.

Evaluating Cardiovascular Treatments (5.25)

• Medication: Cholesterol and blood pressure management.
• Surgical Options: Coronary artery bypass, stents.
• Lifestyle Changes: Diet, exercise, stress management.