Answers to End-of-Chapter Questions
15. In the three types of passive transport (diffusion, facilitated diffusion, and osmosis), the
electrochemical gradient provides the source of energy rather than the cell having to ex-
18. The endosymbiotic theory proposes an explanation for why mitochondria and chloro-
plasts have 70S ribosomes, circular DNA, and two membranes. The theory states that
Critical Thinking
1. A chemical that prevents Golgi function would cause a variety of problems in the human
body, all related to secretion. The respiratory tract would dry out, making breathing and
3. Bacterial ribosomes differ from eukaryotic ribosomes in structure and some aspects of
function. Drugs targeting those biochemical differences may be toxic to bacteria but
4. When the contents of the digestive system are hypertonic as a result of salt secretion,