b)carbohydrates cholesterol peripheral proteins
Explanation:
- Integral proteins: those that cross the membrane and appear on both sides of the phospholipid layer. Most of these proteins are glycoproteins, proteins that have several monosaccharides attached. The carbohydrate part of the molecule is always from each outside the cell
- Peripheral proteins: they are not spread across the bilayer but are attached to the internal or external surfaces of the bilayer and easily separated from it.
The nature of membrane proteins determines their function:
- Channels: integral proteins (usually glycoproteins) that act as pores through which certain substances can enter or leave the cell
- Conveyors: they are peripheral proteins that change shape to give way to certain products
- Receptors: These are integral proteins that recognize certain molecules to which they bind or attach. These proteins can identify a hormone, a neurotransmitter or a nutrient that is important for cellular function. The molecule that binds to the receptor is called ligand.
- Enzymes: they can be integral or peripheral and serve to catalyze reactions at the membrane surface
- Cytoleskeleton anchors: these are peripheral proteins that are found in the cytosol part of the membrane and are used to fix the cytoskeleton filaments.
