Chapter 01: Principles of Cell Function MULTIPLE CHOICE 1. The subcellular structure that degrades proteins is called the: a. Tight junction b. Mitochondria c. Lysosome d. Plasma membrane e. Ribosome ANS: C 2. An experiment is done to measure the uptake of an amino acid into a cell. The following data are obtained: If Na+ is removed from the extracellular bathing solution, or if a drug is added that prevents the cell from making adenosine triphosphate (ATP), the uptake of amino acid into the cell is markedly reduced. According to this information, which of the following mechanisms is probably responsible for the transport of the amino acid into the cell? a. Passive diffusion through the lipid bilayer b. Uniporter c. Transport ATPase d. Na+ symporter e. Na+ antiporter ANS: D 3. A membrane permeable by only Na+ separates two compartments containing Na2SO4, shown as follows: