MC

Cell study

🔹 Prokaryotes vs. Eukaryotes

  • Prokaryotes: No nucleus, no membrane-bound organelles, circular DNA, small (1–10 µm), unicellular (bacteria, archaea).

  • Eukaryotes: Nucleus, membrane-bound organelles, linear DNA, larger (10–100 µm), unicellular or multicellular (plants, animals, fungi, protists).

🔹 Cell Types & Structures

Prokaryotic Cell: cell wall, plasma membrane, cytoplasm, nucleoid (DNA), ribosomes, pili, flagella, capsule (sometimes).
Animal Cell: nucleus, mitochondria, ER (rough/smooth), Golgi, lysosomes, ribosomes, cytoskeleton, centrioles, plasma membrane.
Plant Cell: nucleus, mitochondria, ER, Golgi, ribosomes, plasma membrane, cell wall, chloroplasts, central vacuole, plasmodesmata.

🔹 Cell Membrane

  • Phospholipids: Hydrophilic heads (water-loving), hydrophobic tails (water-fearing).

  • Fluid Mosaic Model: Membrane is flexible (fluid), with proteins, lipids, and carbs scattered (mosaic).

  • Cholesterol: Stabilizes fluidity (prevents too rigid in cold, too fluid in heat).

  • Proteins:

    • Integral: Span the bilayer, transport/receptors.

    • Peripheral: Surface, support/signaling.

  • Carbohydrates:

    • Oligosaccharides: Recognition.

    • Glycolipids & Glycoproteins: Cell communication, immune response.

🔹 Membrane Transport

  • Passive transport: No ATP.

    • Diffusion = molecules from high → low.

    • Osmosis = water diffusion.

    • Facilitated diffusion = with protein helpers.

  • Active transport: Requires ATP, moves against gradient.

  • Endocytosis: Cell engulfs material.

  • Exocytosis: Cell expels material.

🔹 Solutions & Water Potential

  • Hypertonic: Cell loses water, shrinks.

  • Isotonic: Equal solute, no net change.

  • Hypotonic: Cell gains water, swells.

  • Water potential: Ψ = Ψs + Ψp; solute potential Ψs = -iCRT.

  • Potato core lab: Isotonic point = when % change in mass = 0.

🔹 Lipids & Membrane Fluidity

  • Saturated fats: No double bonds, solid at room temp, less fluid.

  • Unsaturated fats: Double bonds, bent chains, liquid at room temp, more fluid.

🔹 Cell Cycle & Mitosis

  • Checkpoints:

    • G1: DNA damage check.

    • G2: DNA replication check.

    • M: Chromosome attachment check.

  • Mitosis steps:

    1. Prophase – Chromosomes condense, spindle forms.

    2. Metaphase – Chromosomes line up.

    3. Anaphase – Sister chromatids separate.

    4. Telophase – Nuclei reform, chromosomes decondense.
      (Cytokinesis = cytoplasm division).

  • MPF (Maturation-Promoting Factor): Cyclin + CDK complex → drives G2 → M transition.

🔹 Cancer & Cell Regulation

  • Benign tumor: Non-cancerous, localized.

  • Malignant tumor: Cancerous, can spread (metastasize).

  • Immune evasion: Cancer cells hide markers, suppress immune response, mutate quickly.

🔹 Cell Communication

  • Direct contact: Gap junctions (animals), plasmodesmata (plants).

  • Chemical signals: Hormones, neurotransmitters, immune signaling (e.g., cytokines from T-cells).

✅ This guide gives you definitions, differences, and functions all in one place.

Do you want me to also make a visual version (diagrams for cells, mitosis, and membranes) so you can study both text + images together?