Question

1. how does the cell membrane maintain homeostasis?
2. describe the structure of the cell membrane.
3. explain diffusion and osmosis.
4. why does a cell need to be able to perform active transport?
5. what is endocytosis and exocytosis?

Explanation:

1. The cell membrane maintains homeostasis by regulating the movement of substances in and out of the cell. It is selectively permeable, allowing some substances to pass through while blocking others. This helps to maintain a stable internal environment.
2. The cell membrane is composed of a phospholipid bilayer with embedded proteins. The phospholipids have a hydrophilic (water - loving) head and a hydrophobic (water - fearing) tail. The proteins in the membrane can be involved in transport, signaling, and structural support.
3. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Osmosis is the diffusion of water across a selectively permeable membrane.
4. A cell needs to be able to perform active transport because it allows the cell to move substances against their concentration gradient (from low to high concentration). This is important for processes such as maintaining ion gradients, taking in nutrients when they are in low concentration outside the cell, and removing waste products.
5. Endocytosis is the process by which a cell takes in substances by engulfing them with its membrane. Exocytosis is the process by which a cell releases substances by fusing a vesicle with its membrane.

Answer:

1. The cell membrane maintains homeostasis by regulating the movement of substances in and out of the cell.
2. The cell membrane is composed of a phospholipid bilayer with embedded proteins.
3. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Osmosis is the diffusion of water across a selectively permeable membrane.
4. A cell needs to be able to perform active transport because it allows the cell to move substances against their concentration gradient.
5. Endocytosis is the process by which a cell takes in substances by engulfing them with its membrane. Exocytosis is the process by which a cell releases substances by fusing a vesicle with its membrane.