ANSWER KEY AND EXPLANATIONS:
1. Which statement best describes a difference between prokaryotic cells and eukaryotic cells?
A. The presence of both DNA and ribosomes in prokaryotic cells indicates that they are more complex than eukaryotic cells.
B. The larger size of prokaryotic cells indicates that they are more complex than eukaryotic cells.
C. The presence of membrane-bound organelles in eukaryotic cells indicates that they are more complex than prokaryotic cells.
D. The larger size of eukaryotic cells indicates that they are more complex than prokaryotic cells.
A. Both cell types contain DNA and ribosomes; prokaryotes have less-complex cell organization.
B. Prokaryotes have less-complex cell organization and are generally smaller than eukaryotes.
C. ANSWER: Eukaryotes are more complex because they have organelles that are membrane bound, such as the nuclei which contain their DNA. Prokaryotes have DNA, but it is not bound by a membrane as in eukaryotes.
D. A high surface-area-to-volume ratio usually increases cell efficiency; therefore, larger cells are usually cells are usually less efficient than smaller cells.
2. Alveoli are microscopic air sacs in the lungs of mammals. Which statement best describes how the structure of the alveoli allows the lungs to function properly?
A. They increase the amount of energy transferred from the lungs to the blood.
B. They increase the flexibility of the lungs as they expand during inhalation.
C. They increase the volume of the lungs, allowing more oxygen to be inhaled.
D. They increase the surface area of the lungs, allowing efficient gas exchange.
A. The structure of the alveoli has little impact on the lung’s ability to transfer energy.
B. The structure and function of the alveoli has little impact on the flexibility of lung tissue.
C. The millions of alveoli in the lungs of mammals decrease the total volume of the lungs.
D. ANSWER: The millions of alveoli in mammals greatly increase the surface area of the lungs, thereby providing a larger surface area for gas exchange.