Question

multiple select question select all that apply choose all functions typically carried out by membrane proteins. code for the production of new polynucleotides transport oxygen into the cell receive external chemical messages connect adjacent cells and hold them together attach the membrane to the cytoskeleton

Explanation:

Membrane proteins have various functions. They can act as receptors to receive external chemical messages, help in cell - cell adhesion by connecting adjacent cells, and attach the membrane to the cytoskeleton. Transport of oxygen into the cell is mainly done by hemoglobin (not membrane proteins in general). And coding for the production of new polynucleotides is the function of nucleic acids, not membrane proteins.

Answer:

C. Receive external chemical messages
D. Connect adjacent cells and hold them together
E. Attach the membrane to the cytoskeleton