Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Which type of macromolecule controls most of the cell membrane's specific functions?

1. Carbohydrates

2. Nucleic Acids

3. Proteins

4. Lipids

The correct answer is: Proteins

Proteins play a crucial role in controlling the specific functions of the cell membrane. These functions include the transport of molecules in and out of the cell, communication between cells, and the facilitation of enzymatic reactions. Membrane proteins can be broadly categorized into integral proteins and peripheral proteins. Integral proteins, for example, span the entire membrane and serve as channels or carriers for molecules, while peripheral proteins are attached to the surface of the membrane and can act as enzymes or play a role in cell signaling. Carbohydrates, while they are important for cell recognition and communication, primarily function as recognition sites on the cell surface rather than controlling membrane functions directly. Nucleic acids are involved in genetic information storage and transmission, but they do not participate in the membrane's structural or functional roles. Lipids form the structural foundation of the cell membrane, providing a barrier for the cell, but they do not facilitate the specific functions that proteins do. Ultimately, it is the diverse roles of proteins that allow the membrane to perform its various specialized functions efficiently.