Medical Biology First Class - Cell Structure

Cell Definition and Examples

• A cell is the smallest unit capable of performing life functions.
• Examples of cells include:
  • Amoeba Proteus: A single-celled organism.
  • Plant Stem: Composed of plant cells.
  • Bacteria: Prokaryotic cells.
  • Red Blood Cell: Specialized for oxygen transport.
  • Nerve Cell: Responsible for transmitting signals.

Typical Animal and Plant Cells

• Animal cells have a flexible membrane and lack a cell wall.
• Plant cells have a rigid cell wall in addition to the cell membrane.

Cell Membrane and Cell Wall

• Cell Membrane:
  • Outer membrane controlling movement in and out of the cell.
  • Composed of a double lipid layer.
• Cell Wall:
  • Found in plant cells and bacteria.
  • Provides support and protection.

Cell Nucleus and Components

• Nucleus:
  • Directs cell activities and contains genetic material (DNA).
  • Separated from the cytoplasm by the nuclear membrane.
• Nuclear Membrane:
  • Encloses the nucleus with two layers, allowing selective material transport.
• Chromosomes:
  • Found in the nucleus; made of DNA containing genetic instructions.
• Nucleolus:
  • Located within the nucleus; synthesizes RNA for protein production.

Cytoplasm and Organelles

• Cytoplasm:
  • Gel-like substance surrounding organelles, containing hereditary material.
• Endoplasmic Reticulum:
  • Moves materials within the cell; includes:
    • Smooth ER: Lacks ribosomes; involved in lipid synthesis.
    • Rough ER: Contains ribosomes; aids in protein synthesis.
• Ribosomes:
  • Thousands present in each cell; sites of protein synthesis, located on rough ER and freely in cytoplasm.

Energy and Transport Organelles

• Mitochondria:
  • Produces energy via chemical reactions by breaking down fats and carbohydrates; regulates cellular material balance.
• Golgi Bodies:
  • Responsible for protein packaging; moves materials within and outside the cell.

Digestive and Storage Organelles

• Lysosome:
  • Functions as the digestive plant; breaks down waste; cell can break down if it ruptures.
• Vacuoles:
  • Membrane-bound sacs for storage, digestion, and waste removal; helps maintain plant cell shape and contains water solution.

Chloroplasts

• Chloroplasts:
  • Found in plant cells; contain chlorophyll and are the site of photosynthesis.

This quiz covers essential concepts of cell structure and function, aimed at first-class medical laboratory technology students. Explore the various types of cells, including examples like amoeba, plant stem, and nerve cells, to enhance your understanding of human biology.