Question

describe the function of ONE component if a cell membrane, how its shape is important for this role, how the functional groups and intermolecular forces of attraction contribute to its shape. 6 marks

Answer 1

Carbohydrates

Plasma membranes contain carbohydrates, predominantly glycoproteins, but with some glycolipids (cerebrosides and gangliosides). Carbohydrates are important in the role of cell-cell recognition in eukaryotes; they are located on the surface of the cell where they recognize host cells and share information, viruses that bind to cells using these receptors cause an infection. For the most part, no glycosylation occurs on membranes within the cell; rather generally glycosylation occurs on the extracellular surface of the plasma membrane. The glycocalyx is an important feature in all cells, especially epithelia with microvilli. Recent data suggest the glycocalyx participates in cell adhesion, lymphocyte homing, and many others. The penultimate sugar is galactose and the terminal sugar is sialic acid, as the sugar backbone is modified in the Golgi apparatus. Sialic acid carries a negative charge, providing an external barrier to charged particles.

To recognize how carbohydrates function in living cells, we must understand their chemical structure. The structure of carbohydrates determines how energy is stored in carbohydrate bonds during photosynthesis and how breaking these bonds releases energy during cellular respiration.

Carbohydrate monomers, short chains, and polymers perform important cellular functions to maintain life. The number and type of monosaccharides used, as well as the position of the bond between them, determines the three-dimensional structure of each carbohydrate.