🧬

Lecture on Cell Structure and Organization

May 21, 2025

View transcript

T7 Science Lecture: Life and Physical Science

Overview

  • Focus on cell structure, function, and organization.
  • Biological systems are structured in layers: cells, tissues, organs, organ systems, organism.

Hierarchical Structure of Biological Systems

  1. Cells

    • Most elementary unit of life.
    • Can house organelles, biomolecules, atoms, and subatomic particles.
    • Fundamental unit in all living things: bacteria, fungi, plants, animals.

  2. Tissues

    • Formed by groups of cells performing unified functions.
    • Example: Cardiac muscle tissue.

  3. Organs

    • Composed of tissues working together.
    • Examples: Heart, lungs, kidneys.

  4. Organ Systems

    • Collaboration of organs to perform life functions.
    • Example: Digestive system includes stomach, intestines, liver.

  5. Organism

    • Made up of interconnected organ systems.

Practice Question

  • Sequence of biological hierarchy: Cells, tissues, organs, organ systems, organisms.

Modern Cell Theory

  • Cells are the fundamental unit of life.
  • Living entities are composed of cells (unicellular or multicellular).
  • Cells arise from existing cells.

Cellular Classification

  • Prokaryotes: No nucleus, no membrane-bound organelles (e.g., bacteria).
  • Eukaryotes: Have nucleus and membrane-bound organelles (e.g., fungi, plants, animals).

Organelle Functions

  1. Cell Membrane (Plasma Membrane):

    • Selective permeability for homeostasis.

  2. Cytoplasm:

    • Jelly-like substance supporting cell’s internal structures.

  3. Cytoskeleton:

    • Provides structural support and aids cellular movement.

  4. Ribosomes:

    • Not membrane-bound, for protein synthesis.

  5. Nucleus (Eukaryotes):

    • DNA housed and stored.
    • Manages cell operations.
    • Contains nucleolus for ribosome assembly.

  6. Endoplasmic Reticulum (ER):

    • Rough ER: With ribosomes, synthesizes proteins.
    • Smooth ER: Detoxification, lipid synthesis.

  7. Golgi Apparatus:

    • Packaging and distribution of cell products.

  8. Mitochondria:

    • ATP production via cellular respiration.

  9. Chloroplasts (Plants):

    • Photosynthesis, contain green pigment.

  10. Lysosomes:

    • Break down biomolecules, cellular debris.

  11. Vacuoles:

    • Storage, maintain pressure, sequester materials.

Practice Questions

  • Protein Synthesis: Assembled by ribosomes using mRNA.
  • Powerhouse of the Cell: Mitochondria produce ATP.

Conclusion

  • Understanding of cell structure, function, and organization.
  • Additional resources available at Nurse Chunk Store.

This summary captures the key points and major themes of the lecture on cell structure, function, and organization, providing a clear overview for study and review.

Full transcript