Atar Notes BIO 34 Lecture - July: Immunology and Pathogens 🧬

Introduction

• Presenter: LZ
• Acknowledgement: Warry and Bong people of the Kooler Nations
• What is Atar Notes?
  • Lectures for high school students, VCE and other states
  • Resources: study notes, discussion forums, ATAR calculators, study guides
  • Visit the ATAR Notes website for more resources

Lecture Overview

• Unit 4, Area of Study 1: Immunity
• Immune system basics: innate and adaptive immunity
• Study strategies: videos, diagrams, flowcharts
• Importance of experimental design
• Continual revision of Unit 3 content
• Awareness of study design changes

Pathogens

General Definitions

• Pathogens: Biological agents that cause disease
• Cellular vs. Noncellular: Key distinction in immunity content

Bacteria

• Structure: Unicellular prokaryotes; reproduce by binary fission
• Roles: Helpful (gut flora) vs. harmful (pathogenic)
• Classification: Shapes (cocci, bacilli, spirilla), cell wall (peptidoglycan)
• Mechanisms: Exotoxins, endotoxins, tissue invasion, nutrient consumption
• Recognition: Parts like flagella and pili as antigens

Viruses

• Definition: Noncellular, obligate intracellular pathogens
• Reproduction: Hijack host's cellular machinery for reproduction
• Virus Types: DNA, RNA, bacteriophages
• Viral Structure: Capsid, genetic material, spike proteins
• Mechanism: Infects cells, replicates, new virions released
• Importance: Always noncellular

Prions

• Definition: Misfolded proteins, noncellular
• Effects: Neurological disorders, often transmissible from animals
• Examples: Mad Cow Disease

Fungi, Protozoa, and Worms

• Fungi: Eukaryotic, examples include tinea, athlete's foot
• Protozoa: Single-celled eukaryotes, often parasitic (e.g., Plasmodium causing malaria)
• Worms: Includes tapeworms, liver flukes, visible parasitic worms

Immunity

Antigens

• Definition: Molecules capable of inducing an immune response
• Self vs. Non-self Antigens: Self-antigens (MHC markers) help immune cells distinguish body cells from pathogens
• MHC Class I and II:
  • MHC I on all nucleated cells; present cytosolic proteins
  • MHC II on immune cells; present foreign antigens

Immune System Overview

Innate Immunity

• First Line of Defense: Physical, chemical, and microbiological barriers
  • Examples: Intact skin, mucus, stomach acid, lysozymes, microbiome balance
• Second Line of Defense: General immune cells and mechanisms
  • Key cells: Macrophages, neutrophils, mast cells, natural killer cells, eosinophils
  • Support proteins: Complement proteins, cytokines, interferons
  • Inflammatory Response: Key symptoms and mechanisms

Adaptive Immunity

• Key Cells: B cells (plasma cells and memory B cells) and T cells (helper T cells, cytotoxic T cells)
• Important Concepts: Specificity, memory, clonal expansion, antigen presentation
• Processes: T helper cell activation, B cell differentiation, cytotoxic T cell action
• Receptors: Importance of specific antigen-receptor binding

Response to Allergens

• Allergic Response: Overactive immune response to non-harmful substances
• Mechanism: Priming of IgE antibodies on mast cells, release of histamine on subsequent exposures

Vaccination

• Principle: Induces memory cell formation without causing disease
• Types: Inactivated, attenuated pathogens
• Herd Immunity: Community-level protection when a high percentage is immunized

Monoclonal Antibodies

• Production: Using mouse models, targeting specific epitopes on antigens
• Applications: Cancer treatment, autoimmune diseases

Disease and Public Health

• Reemerging Pathogens: Known pathogens returning due to travel and global connectivity
• New Pathogens: Emergence of diseases with no prior exposure (e.g., COVID-19)

Historical Examples

• Impacts of Colonization: Spread of diseases like smallpox to populations without prior exposure/immunity

Experimental Design and Ethics

Key Concepts

• Variables: IV (independent), DV (dependent), controlled variables
• Groups: Experimental vs. control groups
• Validity and Reliability: Accurate, reproducible results
  • Reproducibility: Different person, different time
  • Repeatability: Same person, same environment
• Errors: Random (e.g., environmental fluctuations) vs. systematic (e.g., faulty equipment)

Data Types

• Qualitative: Descriptive, subjective
• Quantitative: Numerical, objective

Bioethics

• Principles: Integrity, Justice, Beneficence, Non-Maleficence, Respect
• Approaches: Consequences-based, Duty-based, Virtues-based

Exam Study Tips

• Practice Questions: Essential for understanding and technique
• Address Weaknesses: Focus on areas needing improvement
• Ask Questions: Utilize teachers, peers, forums
• Continual Revision: Especially for Unit 3 content
• Exam Practice: Timed conditions, reading time strategy

Personal Study Tips

• Visual Learning: Diagrams, videos, flowcharts
• Mind Maps and Flashcards: Structure around the study design, link areas of study
• Take Breaks: Prevent burnout, maintain mental health

Conclusion

• Continual Revision: Vital for understanding and retaining information
• Utilize Resources: Various available through ATAR Notes
• Email for Questions: [email protected]

Wishing everyone good luck with their bio studies and future exams!