Cell 1

Study Notes

Somatic cells: All body cells except sex cells.
Sex cells: Reproductive cells including male sperms and female oocytes (eggs).

The cell is composed of:
- Cytoplasm: All materials inside the cell and outside the nucleus.
- Nucleus: Contains the cell's genetic material.
- Cell membrane: Outermost layer that separates the cell from its environment.

Physical isolation: Acts as a barrier.
Sensitivity to environment: Responsive to extracellular fluid composition and chemical signals.
Regulates exchange: Controls the movement of ions, nutrients, waste, and cellular products.
Structural support: Provides structure for cell-to-cell and cell-to-tissue interactions.

Cell-cell junctions
Enzymes: Catalyze reactions.
Transporters: Move substances across the membrane through channels or carriers.
Recognition: Provide identification for other cells.
Anchors: Attach to cytoskeleton for structural support.
Receptors: Bind to ligands, triggering cellular responses.

Carbohydrates are part of complex molecules like glycolipids, glycoproteins, and proteoglycans.
The glycocalyx is the layer of carbohydrates that extends outside the cell membrane.
Glycocalyx functions:
- Anchoring and protection.
- Lubrication and locomotion.
- Specificity in binding (receptors).
- Recognition (immune response).

Cytosol: Intracellular fluid containing dissolved materials like nutrients, ions, proteins, and waste.
Organelles: Structures with specific functions, further divided into:
- Nonmembranous organelles: No membrane, in direct contact with the cytosol.
- Membranous organelles: Enclosed by a membrane, isolated from cytosol.

Cytoskeleton: Provides structure, strength, and flexibility to the cytoplasm.
- Composed of: - Microfilaments: Thin filaments responsible for cell movement. - Intermediate filaments: Intermediate in size, provide structural support. - Thick filaments: Found in muscle cells, involved in muscle contraction. - Microtubules: Hollow tubes, support structure and transport.
Microvilli: Finger-like projections that increase surface area.
Centrioles: Role in cell division.
Cilia: Hair-like structures for movement.
Ribosomes: Sites of protein synthesis.
Proteasomes: Break down and recycle proteins.

Endoplasmic reticulum: Network of interconnected membranes.
- Rough ER: Has ribosomes attached, involved in protein synthesis.
- Smooth ER: No ribosomes, involved in lipid synthesis and detoxification.
Golgi apparatus: Modifies and packages proteins.
Lysosomes: Contain enzymes for digestion and waste removal.
Peroxisomes: Contain enzymes for detoxification.
Mitochondria: Powerhouses of the cell, responsible for ATP production.