Answer:
<em><u>The correct option is A) carbohydrate chain</u></em>
Explanation:
The carbohydrate chain present in the cell membrane helps determine the characteristics of the cell and it also helps to identify the chemical signals from outside the cell. Hence, option A is correct.
Other options, like option B, is not correct because the function of the cholesterol in the cell membrane is to prevent the fatty acids from sticking together. Option D is not correct because transport proteins help some molecules to move inside the cell.
The OH on the lower right of lysine and the H on the lower left of valine combine to form a molecule of water (H2O) and detach in a process known as a dehydration reaction when the two amino acids bond. The C on the right side of lysine then single bonds with the N on the left side of valine. This bond is termed a peptide bond. All the other bonds remain unchanged.