Question

match each molecule to its function in the cell membrane.
lipids carbohydrates proteins
function molecule
allow the cell to be recognized by other cells
give the membrane its flexibility
pump large molecules across the membrane

Explanation:

• Carbohydrates: They are involved in cell - cell recognition. Glycoproteins (proteins with attached carbohydrate chains) and glycolipids (lipids with attached carbohydrate chains) on the cell membrane surface act as markers for cell recognition.
• Lipids (specifically phospholipids and cholesterol): Phospholipids form the basic bilayer structure of the membrane. Cholesterol, a type of lipid, helps in maintaining the fluidity (flexibility) of the membrane. At high temperatures, it restricts the movement of phospholipids to prevent excessive fluidity, and at low temperatures, it prevents the membrane from becoming too rigid.
• Proteins: Integral proteins can act as pumps (e.g., sodium - potassium pump). These proteins use energy (usually in the form of ATP) to move large molecules (such as ions) across the cell membrane against their concentration gradient.

Answer:

• allow the cell to be recognized by other cells: carbohydrates
• give the membrane its flexibility: lipids
• pump large molecules across the membrane: proteins