Overview of Eukaryotic Cell Organelles

Dr. O provides a high-level overview of the organelles in a typical eukaryotic cell, such as human cells. Future videos will cover these organelles in more detail.

Cytoplasm

• Definition: Everything inside the plasma membrane, except the nucleus.
• Components:
  • Cytosol: Fluid portion
  • Organelles: Structures within the cytosol

Plasma Membrane

• Function: Selectively permeable barrier that regulates entry and exit of substances.
• Structure: Phospholipid bilayer containing cholesterol.
  • Cholesterol: Strengthens the membrane, eliminating the need for a cell wall (unlike plants and bacteria).

Nucleus

• Components:
  • Nucleolus: Site of ribosomal RNA (rRNA) synthesis and ribosome subunit assembly.
  • Nuclear Envelope: Membrane protecting the nucleus, similar to the plasma membrane.
  • Nuclear Pores: Openings for RNA to exit the nucleus.
• Function: Controls protein synthesis (DNA -> RNA -> Protein).

Endoplasmic Reticulum (ER)

• Rough ER:
  • Structure: Studded with ribosomes.
  • Function: Modifies and packages proteins.
• Smooth ER:
  • Structure: Lacks ribosomes.
  • Function: Synthesizes lipids and carbohydrates, detoxifies substances.

Cilia

• Function: Movement
  • In single-celled organisms: Propel the cell.
  • In human cells: Move materials across cell surfaces.
• Note: Bacteria do not have cilia.

Golgi Complex (Apparatus)

• Function: Modifies, packages, and ships materials in vesicles, acting as a shipping and receiving center.

Peroxisomes

• Function: Break down fats and organic compounds, neutralize toxic byproducts.

Lysosomes

• Function: Digestive system of the cell, breaks down damaged organelles and foreign substances.

Cytoskeleton

• Microtubules and Microfilaments: Provide cell shape and aid in material transport.
  • Microtubules: Hollow structures.
  • Microfilaments: Solid structures.

Mitochondria

• Function: Powerhouse of the cell, produces 95% of ATP.
• Note: Glycolysis (initial ATP production) occurs outside mitochondria.

Ribosomes

• Function: Site of protein synthesis (translation).
• Types:
  • Free Ribosomes: Synthesize proteins for the cell's own use.
  • Fixed Ribosomes: Synthesize proteins for export.

Centrosome

• Components: Contains two centrioles, essential for cell division (mitosis).

Flagella

• Function: Movement, uses a whip-like action unlike bacterial flagella.

Dr. O plans to create more detailed videos on specific organelles and encourages viewers to stay tuned for those discussions.