Question

1. sb1.a dok1 which set of functions is directly controlled by the cell membrane?

a. protein synthesis, respiration, digestion of food molecules
b. active transport, recognition of chemical messages, protection
c. enzyme production, elimination of large molecules, duplication of dna codes
d. release of atp molecules, regulation of cell reproduction, food production

Explanation:

The cell membrane (plasma membrane) is primarily responsible for controlling what moves in and out of the cell, recognizing chemical signals (like hormones), and providing a protective barrier for the cell.

• Option A: Protein synthesis occurs in ribosomes, respiration in mitochondria/chloroplasts, and digestion in lysosomes; none are controlled by the cell membrane.
• Option C: Enzyme production is linked to ribosomes/ER, DNA duplication to the nucleus, and large molecule elimination to vesicles/lysosomes; not membrane functions.
• Option D: ATP release is from mitochondria/chloroplasts, cell reproduction regulation from the nucleus, and food production from chloroplasts; unrelated to the cell membrane.
• Option B: Active transport uses membrane proteins to move substances against a gradient, membrane receptors recognize chemical messages, and the membrane acts as a protective barrier for the cell's interior. All these are direct functions of the cell membrane.

Answer:

B. active transport, recognition of chemical messages, protection