Unit 2: Keeping Healthy (Biology B OCR GCSE)

Pathogens 🦠

• Bacteria: Single-celled organisms, can cause infections.

• Viruses: Infect cells and reproduce inside them.

• Fungi: Can be single-celled or multicellular, e.g., yeast and mushrooms.

Protists: Single-celled eukaryotes, sometimes cause disease.

Communicable Diseases 🤒

• Spread through direct contact, airborne particles, surfaces, or contaminated food/water.

• Examples: Influenza, Salmonella, Malaria.

Non-Communicable Diseases 🚫

• Result from genetic, environmental, or lifestyle factors.

• Examples: Diabetes, Cancer.

Important definitions

• Antibiotic: Medicine that kills bacteria.

• Virus: Pathogen that reproduces inside host cells.

• Fungi: Eukaryotic pathogens, e.g., yeast.

• Protist: Single-celled eukaryotes, sometimes pathogenic.

The defenses

• Mechanical barriers: Skin, nose hairs.

• Chemical barriers: Mucus, stomach acid, tears.

• Bacterial barriers: Gut bacteria.

Immune System 🧬

• White blood cells: Attack and destroy pathogens.

• Antibodies: Proteins that neutralize pathogens.

Plant Defenses 🌿

• Physical barriers: Cell wall, waxy cuticle.

• Antimicrobial substances: Chemicals that kill pathogens.

Key terms!

• Antibody: Protein produced by white blood cells.

• Antigen: Protein on pathogen surface.

• Immune system: Body's defense against pathogens.

Plant Disease Prevention 🌱

• Regulate infected plant movement.

• Sourcing healthy plants.

• Destroying infected plants.

Human and Animal Disease Prevention 🧴

• Contraception.

• Sterilizing wounds.

• Hygiene and sanitation.

• Vaccination.

• Restricting travel.

Key terms!

• Vaccination: Introducing inactive pathogens to stimulate immunity.

• Contraception: Methods to prevent pregnancy.

• Sterilization: Removing microorganisms from equipment.

Diagnosis Methods 🔬

• Symptom observation.

• Cell counting.

• Culture growth.

• Microscopy and staining.

• Antimicrobial testing.

Genome analysis.

Aseptic Techniques 🧼

• Sterilize equipment.

• Limit sample exposure.

Monoclonal Antibodies 🧪

• Used in diagnostic tests like pregnancy tests.

Key terms!

• Aseptic techniques: Methods to prevent contamination.

• Monoclonal antibodies: Lab-made antibodies for specific antigens.

Risk Factors ⚠

• Unhealthy diet: High fats/sugar.

• Lack of exercise.

• Age.

• Genetic predispositions.

• Environmental factors: UV radiation.

• Smoking and drugs.

Disease Interactions 🔄

• Autoimmune diseases.

• Viruses triggering cancers.

• Preventative diseases: Sickle cell anemia prevents malaria.

Key terms!

• Autoimmune disease: Immune system attacks the body.

• Correlation: Relationship between two variables.

• Genetic predisposition: Increased risk of disease due to genetics.

Medicines 💊

• Painkillers: Reduce symptoms.

Antibiotics: Kill bacteria.

Cardiovascular Disease Treatments ❤

• Lifestyle changes.

• Drugs: Statins.

• Stents: Widen blood vessels.

• Heart transplants.

New Medicine Development 🧬

• Screening.

• Pre-clinical trials.

• Clinical trials.

Monoclonal Antibodies 🧪

• Used for cancer treatment by targeting specific cancer cells.

Key terms!

• Chemotherapy: Cancer treatment using drugs.

• Heart transplant: Replacing a damaged heart.

• Statins: Drugs lowering cholesterol.

• Stent: Wire mesh widening arteries.