Which molecules strengthen the cell membrane?

Which molecules strengthen the cell membrane?

• A. Proteins in membrane
• B. Carbohydrates
• C. Cholesterol molecules
• D. Nucleic acids

Answer: (B)

Cholesterol molecules embedded in the phospholipid bilayer regulate membrane fluidity and stability. By inserting between the fatty acid tails, they prevent the membrane from becoming too fluid at higher temperatures and from becoming too rigid at lower temperatures, which helps maintain integrity and controls permeability to small molecules. Carbohydrates on the membrane surface mainly serve roles in cell recognition and signaling rather than strengthening the bilayer. Nucleic acids are not components of the membrane, and while membrane proteins contribute to structure and function, they don’t primarily stiffen the bilayer. Therefore, cholesterol strengthens the cell membrane.

Cholesterol molecules embedded in the phospholipid bilayer regulate membrane fluidity and stability. By inserting between the fatty acid tails, they prevent the membrane from becoming too fluid at higher temperatures and from becoming too rigid at lower temperatures, which helps maintain integrity and controls permeability to small molecules. Carbohydrates on the membrane surface mainly serve roles in cell recognition and signaling rather than strengthening the bilayer. Nucleic acids are not components of the membrane, and while membrane proteins contribute to structure and function, they don’t primarily stiffen the bilayer. Therefore, cholesterol strengthens the cell membrane.