CHAPTER 4: CELL MEMBRANE AND TRANSPORT
Cell membranes are two layered structures made of phospholipids. The name for the model of the membrane is the fluid mosaic model. The cell membrane contains proteins (assist with transport across the membrane),receptor molecules (outside the membrane; allows other cells to determine which type of cell it is), and cholesterol (keeps the membrane fluid and prevents it from becoming too rigid). The cell membrane serves as a wall that only lets certain things in or out.
Roles that the cell membrane serves in:
The semi-permeable membrane provides protection to the cell, allows necessary materials in and unwanted materials out, and holds the cell together. Through studying and taking the quiz and test, I found it easy to see why cell membranes are vital.
Roles that the cell membrane serves in:
- Endocytosis: the bulk transport of materials inside the cell. There are two types. One type is pinocytosis and involves the bulk transport of liquids into a cell. The second type is phagocytosis and involves the bulk transport of solids into a cell.
- Exocystosis: The bulk transport of materials (ex. waste) outside of the cell.
- Diffusion: net movement of molecules or ions from a region of higher concentration to a region of lower concentration down a gradient as a result of the random movement of particles
- Active transport: movement of molecules or ions through transport proteins across a cell membrane against their concentration gradient using energy from ATP
The semi-permeable membrane provides protection to the cell, allows necessary materials in and unwanted materials out, and holds the cell together. Through studying and taking the quiz and test, I found it easy to see why cell membranes are vital.