Biology

  1. CELL MEMBRANE (PLASMA MEMBRANE)

    • Main Function: Controls entry/exit of substances; maintains homeostasis.

    • Fluid Mosaic Model:

      • Fluid: Molecules move within the membrane.

      • Mosaic: Diverse components embedded.

    • Phospholipid Structure:

      • Hydrophilic head: Water-loving, faces outside/inside.

      • Hydrophobic tails: Water-fearing, face inward.

  2. CELL TRANSPORT

    • Passive Transport (No Energy): High to low concentration.

      • Types:

      1. Diffusion: Movement of small molecules (O₂, CO₂).

      2. Facilitated Diffusion: Uses protein channels (Glucose, polar/large molecules).

      3. Osmosis: Water diffusion toward higher solute concentration.

    • Active Transport (Requires ATP): Low to high concentration.

      • Examples: Ion pumps (sodium-potassium pump), endocytosis, exocytosis.

  3. PHOTOSYNTHESIS

    • Location: Chloroplasts (light energy → chemical energy).

    • Overall Equation: 6CO2 + 6H2O + ext{light} → C6H{12}O6 + 6O2

    • Two Stages:

      1. Light Reactions: Produce ATP, NADPH, and oxygen.

      2. Calvin Cycle: Uses ATP, NADPH, CO₂ to produce glucose.

  4. CELLULAR RESPIRATION

    • Location: Mitochondria; breaks down glucose to produce ATP.

    • Overall Equation: C6H{12}O6 + 6O2 → 6CO2 + 6H2O + ext{ATP}

    • Three Stages: Glycolysis, Krebs Cycle, Electron Transport Chain (ETC).

    • ATP Production: 36-38 ATP (aerobic); 2 ATP (anaerobic).

  5. FERMENTATION

    • Lactic Acid Fermentation: Occurs in animals; produces lactic acid (muscle fatigue).

    • Alcoholic Fermentation: Occurs in yeast; produces alcohol and CO₂.

  6. ENERGY FLOW IN CELLS

    • Flow: Sunlight → Photosynthesis → Glucose → Cellular Respiration → ATP → Cellular Work.

  7. SUPER IMPORTANT TEST FACTS

    • Key concepts on membrane structure, transport processes, photosynthesis, and cellular respiration.