FSC Part 1 Biology Notes

Chapter 1: Cell Biology

Cell Theory

• All living things are composed of cells
• Cell is basic unit of life
• All cells arise from pre-existing cells

Cell Structure

Prokaryotic Cells

• No nucleus (DNA in nucleoid)
• No membrane-bound organelles
• Examples: Bacteria, Blue-green algae

Eukaryotic Cells

• True nucleus
• Membrane-bound organelles
• Examples: Plants, Animals, Fungi

Organelles

• Nucleus: Contains genetic material, controls cell activities
• Mitochondria: Powerhouse - ATP production
• Ribosomes: Protein synthesis
• ER: Transport and synthesis (Rough: proteins, Smooth: lipids)
• Golgi Apparatus: Packaging and secretion
• Chloroplast: Photosynthesis (plants only)
• Centrioles: Cell division
• Lysozymes: Digestion

Chapter 2: Biological Molecules

Carbohydrates

• Monosaccharides: Glucose, Fructose (C₆H₁₂O₆)
• Disaccharides: Sucrose, Lactose, Maltose
• Polysaccharides: Starch, Cellulose, Glycogen

Proteins

Building blocks: Amino acids (20 types).

• Primary: Linear sequence
• Secondary: α-helix, β-pleated sheet
• Tertiary: 3D shape
• Quaternary: Multiple polypeptides

Lipids

• Fats: Triglycerides (glycerol + 3 fatty acids)
• Phospholipids: Cell membrane
• Steroids: Cholesterol, hormones

Nucleic Acids

• DNA: Deoxyribose sugar, double helix, genetic material
• RNA: Ribose sugar, single strand, protein synthesis

Vitamins

• Fat-soluble: A, D, E, K
• Water-soluble: B-complex, C

Chapter 3: Enzymes

Nature

Proteins that act as biological catalysts. Lower activation energy.

Mechanism (Lock and Key)

Substrate fits into active site like key in lock.

Factors Affecting Enzyme Activity

• Temperature: Optimum ~37°C
• pH: Specific for each enzyme
• Substrate concentration: Increases rate until saturation
• Inhibitors: Competitive (compete) / Non-competitive (bind elsewhere)

Cofactors

Non-protein components required for enzyme activity (vitamins, metal ions).

Chapter 4: The Cell Cycle

Interphase

• G1: Growth, protein synthesis
• S: DNA replication
• G2: Preparation for division

Mitosis

Produces 2 identical daughter cells. Used for growth and repair.

1. Prophase: Chromatin condenses, nuclear membrane breaks
2. Metaphase: Chromosomes align at equator
3. Anaphase: Sister chromatids separate
4. Telophase: Nuclear membrane reforms

Cytokinesis

Division of cytoplasm. Cell membrane constricts (animal) / cell plate forms (plant).

Meiosis

Produces 4 genetically different gametes. Two divisions.

• Meiosis I: Reduction division (homologous chromosomes separate)
• Meiosis II: Like mitosis (sister chromatids separate)

Chapter 5: Diversity of Life

Kingdoms

• Monera: Prokaryotes (bacteria, cyanobacteria)
• Protista: Mostly unicellular eukaryotes (Amoeba, Paramecium)
• Fungi: Heterotrophic, cell wall (yeast, mushroom)
• Plantae: Autotrophic, cell wall of cellulose
• Animalia: Heterotrophic, no cell wall

Virus

Acellular, between living and non-living. Requires host to reproduce.

Chapter 6: Kingdom Plantae

Bryophytes

Non-vascular, require water for reproduction. Mosses, liverworts.

Tracheophytes

Vascular plants.

Pteridophytes

Vascular, no seeds. Ferns.

Gymnosperms

Naked seeds, no fruits. Pine, cypress.

Angiosperms

Flowering plants, seeds in fruits.

• Monocots: One seed leaf (grass, wheat)
• Dicots: Two seed leaves (bean, rose)

Chapter 7: Kingdom Animalia

Phylum Classification

• Porifera: Sponges (filter feeders)
• Coelenterata: Jellyfish, Hydra (tentacles, stinging cells)
• Platyhelminthes: Flatworms (tapeworm, liver fluke)
• Nematoda: Roundworms (Ascaris)
• Annelida: Segmented worms (earthworm, leech)
• Arthropoda: Jointed legs (insects, crustaceans, spiders)
• Mollusca: Soft body, shell (snail, clam)
• Echinodermata: Spiny skin (starfish, sea urchin)
• Chordata: Notochord (fish, amphibians, reptiles, birds, mammals)