Biology Lecture Notes

Introduction

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• Follow up with predictive papers, workbooks, or multiple-choice questions.

Taxonomy and Classification

• Developed by Linnaeus.
• Organisms have a 2-part Latin name: Genus (broad category) and Species (specific category).
• Taxonomy evolves with new developments in biology and genetics.
• Three Domain System:
  • Eukaryotes: Organisms with nuclei.
  • Bacteria.
  • Archaea.

Ecosystems

• Community: Plants and animals dependent on each other.
• Abiotic factors: Non-living (light, temperature, water, pH, etc.).
• Biotic factors: Living factors (food, predators, pathogens).
• Changes in factors affect community balance.

Organism Adaptations

• Cacti: Shallow roots, spines, water storage for desert survival.
• Snow Foxes: White color, small ears, thick coat for cold environments.

Scientific Method Tools

• Quadrat: 1m² tool for estimating plant population in fields.
• Transect: Measures changes along a line for environmental study.

DNA and Genetics

• DNA: Deoxyribonucleic acid, double helix structure.
• Mitosis: Cell division into two identical daughter cells; used for growth/repair.
• Meiosis: Two divisions; results in four genetically different cells; used in sexual reproduction.
• Cancer: Uncontrolled cell division leading to benign or malignant tumors.

Genetic Conditions

• Polydactyly: Extra fingers, dominant trait.
• Cystic Fibrosis: Recessive disease, 25% offspring chance if both parents are carriers.

Stem Cells

• Potential to become any cell type.
• Uses in Parkinson’s, injuries, organ growth.
• Ethical concerns due to embryonic stem cells.

DNA Structure and Function

• Base pairing: A-T, C-G.
• Genes: Code for amino acids, fold into proteins.
• Mutations: Mistakes in DNA can alter protein function.
• Non-coding DNA: "Junk" DNA with no known function.

Genetic Inheritance

• Alleles: Different versions of a gene.
• Genotype vs. Phenotype: Genetic makeup vs. observable traits.
• Genetic Crosses: Used to determine offspring probabilities.

Genetic Engineering

• Modifying plant DNA for drought, vitamin production, pest resistance.
• Insulin production using bacterial DNA.
• Concerns over natural interference.

Evolution and Natural Selection

• Charles Darwin: Theory of evolution by natural selection.
• Evidence: Fossils, fast-adapting bacteria.
• Controversies with religious beliefs.

Antibiotic Resistance

• Bacteria evolve resistance quickly due to fast reproduction.
• Overuse of antibiotics accelerates resistance.

Human Body Systems

• Nervous System: Brain, spinal cord, neurons.
• Endocrine System: Hormone production and regulation.

Blood Glucose Regulation

• Insulin lowers blood glucose; glucagon raises it.
• Types of Diabetes: Type 1 (insufficient insulin), Type 2 (insensitivity to insulin).

Pathogens and Disease

• Pathogen types: Viruses, bacteria, fungi, protists.
• Common diseases: HIV, chlamydia, malaria.
• Immune system: Pathogen consumption, antitoxin production, antibody recognition.

Vaccination

• Provides immunity by introducing dead/inactive pathogens.
• Advantages: Herd immunity, disease eradication.
• Disadvantages: Not always effective, potential side effects.

Microbiology Techniques

• Antibiotic Sensitivity Test: Determines bacterial resistance.
• Bacteria division rate: Every 20 minutes under optimal conditions.
• Pathogen spread: Through air, contact, blood, etc.

Conclusion

• Understanding these concepts is crucial for WGSEA biology papers.
• Use available resources to strengthen knowledge.