Question

Write about the membrane proteins and their functions.

Answer 1

Membrane proteins:

1. Membrane proteins are common proteins that are either a part of or interact with biological membranes.
2. Membrane proteins fall into several broad categories depending on their location.
3. These are:

1. Transport proteins:

1. These proteins spend ATP to transfer materials across membranes.
2. The process is active transport because energy is used to transport matter across the channel.

2. Channel proteins:

1. These proteins provide pathways through membranes for some water-soluble, hydrophilic substances (charged and polar molecules).
2. The process used here is facilitated diffusion as energy is not used in transportation.

3. Adhesion proteins:

1. They help in attaching cells to adjacent cells.
2. They also provide anchorage to internal tubules and filaments, providing stability to cells.

4. Recognition proteins:

1. They recognise the identity of the nearby cells.
2. They have short polysaccharide or oligosaccharide chains that extend out from the surface of cells.

5. Electron transfer proteins:

1. These proteins are involved in the movement of electrons from one molecule to another during chemical reactions.

6. Receptor proteins:

1. They initiate certain cell responses after they receive stimulus from hormones or other molecules for them to bind.