The Cell
In biology, the cell is an essential component that makes up living things, but it is not considered an organism on its own. Instead, it functions as the basic unit of life within the biosphere and various biomes.
Cell Theory
The cell has been defined by the Cell Theory, which states that all organisms are composed of one or more cells, and cells are the basic unit of life. Additionally, cells come from preexisting cells.
Cell Types
There are two main types of cells: Eukaryotic and Prokaryotic.
- Eukaryotic Cells: These cells can be found in animals, plants, and humans. They contain membrane-bound organelles and a nucleus.
- Prokaryotic Cells: Prokaryotic cells can be found in bacteria. They lack membrane-bound organelles and do not have a nucleus.
Structure & Organelles of a Cell
Organelles
Organelles are the individual structures present within a cell that carry out specific functions. These include the nucleus, cytoplasm, Golgi Apparatus, SER & BER, nucleolus, microtubules, ribosomes, plasma membrane, mitochondria, and others.
Types of Cells
There are specific types of cells, such as plant cells, animal cells, and prokaryotes (bacteria). Each type of cell contains unique features and organelles that differentiate them from one another.
- Plant Cells contain a cell wall, chloroplasts, a large vacuole, and a plasma membrane.
- Animal Cells are characterized by the presence of lysosomes, centrioles, and vesicles.
- Prokaryotic Cells have a simpler structure with a cell wall, DNA, and ribosomes.
Types of Molecule Movement
Diffusion
Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
Active Transport
This mechanism involves the movement of molecules from a low concentration to a high concentration with the use of energy in the form of ATP.
Endocytosis & Exocytosis
- Endocytosis is the process of bringing large molecules into the cell.
- Exocytosis is the process of expelling large molecules out of the cell.
Both of these mechanisms require energy and are used to transport molecules that are too large to be transferred through the plasma membrane.
Overall, understanding the cell structure and function is crucial to comprehending the complexities of living organisms and the fundamental biology of all life forms.
