Myosin is plentiful in muscle cells, but is not found at all in lens cells. Lens cells contain large amounts of crystallins, which are not found in muscle cells. Why do some proteins appear in one type of cell but not in another?

A. During differentiation, certain genes are added to cells to produce proteins that enable specific functions

B. During differentiation, certain genes are activated to produce proteins that enable specific functions.

C. Differentiated cells produce all proteins but destroy the proteins they do not use.

D. Differentiated cells release unused proteins into the blood for other cells to use.

B

Explanation:

All cells from the body came from a single cell (fertilization of egg and sperm). All the cell have the same instruction in them. They however undergo certain changes base on the site of their function in process described as cell specialization. During this differentiating process, certain genes are activated to produce proteins that enables specific functions. Example include the myosin present in abundance in muscle cells but not in lens cell while the lens cell have crystallins in abundance for it adapted activities which the muscles cells lack. others include the root hair cell specially adapted for absorption, the nerve cells for transmission of electrical impulses. This cells generally have certain character controlled by the activated genes which are repressed in others.