QUIZ 1. What is the major component of cell membranes when it comes to numbers of molecules? a. Intramembranous proteins b. Phospholipids c. Cholesterol d. Glycoproteins Answer: b. Phospholipids make up the majority of the molecules making up the cell membrane. Interestingly, because proteins are heavier, they make up more of the actual mass of the cell than lipids. 2. What do membrane-associated G-protein-coupled proteins do? a. They exchange sodium and potassium ions b. They block the transport of glucose inside the cell c. They affect intracellular changes within the cell d. They help make ATP for membrane processes Answer: c. G-protein-coupled proteins will bind to molecules outside of the cell and affect intracellular changes within the cell itself. They cause signaling molecules to become activated, sending a signal deep within the cell. 3. Where are ribosomes mainly located on an animal cell? a. On rough endoplasmic reticulum b. Within the nucleus c. Membrane-bound within the cytoplasm d. Inside lysosomes Answer: a. The ribosomes are studded along the surface of rough endoplasmic reticulum or RER, which accounts for the “roughness” or rough appearance of the endoplasmic reticulum.
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