Cell Structure And Function

key notes:

1. Introduction to Cells:

  • Definition: Cells are the basic building blocks of all living organisms.
  • All living things are made up of cells, and they perform essential functions to sustain life.

2. Types of Cells:

  • Prokaryotic Cells: Simple cells without a nucleus (e.g., bacteria).
  • Eukaryotic Cells: More complex cells with a nucleus and membrane-bound organelles (e.g., plant and animal cells).

3. Parts of the Cell:

  • Cell Membrane: Protects and supports the cell, regulates what enters and leaves the cell (selectively permeable).
  • Nucleus: The control center of the cell; contains genetic material (DNA).
  • Cytoplasm: Gel-like substance where cell activities occur and where organelles are located.
  • Mitochondria: The powerhouse of the cell; produces energy (ATP) through cellular respiration.
  • Ribosomes: Small structures where protein synthesis occurs.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Studded with ribosomes; involved in protein synthesis.
    • Smooth ER: No ribosomes; involved in lipid synthesis and detoxification.
  • Golgi Apparatus: Packages and transports proteins and lipids within or outside the cell.
  • Lysosomes: Contain digestive enzymes that break down waste materials and cellular debris.
  • Vacuoles: Storage organelles; store nutrients, waste products, or help in maintaining turgor pressure in plant cells.
  • Chloroplasts (in plant cells): Contain chlorophyll and conduct photosynthesis, converting sunlight into food energy.
  • Cell Wall (in plant cells): Provides structural support and protection, made of cellulose.

4. Cell Function:

  • Energy Production: Mitochondria break down glucose to produce energy (ATP) for cell functions.
  • Protein Synthesis: Ribosomes create proteins by reading RNA instructions.
  • Transport: The endoplasmic reticulum and Golgi apparatus help transport proteins and lipids.
  • Waste Removal: Lysosomes break down waste and foreign material.
  • Reproduction: Cells reproduce through processes like mitosis (for growth) and meiosis (for sexual reproduction).

5. Difference Between Plant and Animal Cells:

  • Plant Cells have a cell wall, chloroplasts for photosynthesis, and a large central vacuole.
  • Animal Cells lack a cell wall, chloroplasts, and have smaller vacuoles.

6. Cell Division:

  • Mitosis: Process by which eukaryotic cells divide to produce two genetically identical daughter cells for growth or repair.
  • Meiosis: Cell division that reduces the chromosome number by half, creating gametes (sperm and eggs) for reproduction.

7. Importance of Cells:

  • Understanding cell structure and function helps in studying diseases, medicine, and biotechnology.
  • Cells are essential for life; they perform all vital functions, including energy production, reproduction, and responding to the environment.

Let’s practice!