Basic Characteristics of Human Cells
- Smallest living subdivision of the human body
- Diverse in structure and function (cell physiology)
- Divided intoÂ organelles
â€“Structures and compartments in the cell
â€“Isolation of chemical reactions
â€“Each organelle performs a specific function
Each Cell Has Three Primary Regions
- Plasma MembraneÂ (cell membrane) is made of two layers of phospholipids. The membrane has many proteins embedded in it.Â The plasma membrane regulates what enters and leaves the cell. Many molecules cross the cell membrane by diffusion and osmosis.
- Cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell’s internal sub-structures (called organelles), except for the nucleus. Organelles are membrane-bound “organs” inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the mitochondria, the endoplasmic reticulum, the Golgi apparatus, vacuoles, and lysosomes.
- Nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell’s genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes.