16. Cilia and flagella bend because of _______.
(A) conformational changes in ATP that thrust microtubules laterally
(B) a motor protein called radial spokes
(C) contraction by myosin
(D) a motor protein called dynein

12. The evolution of eukaryotic cells most likely involved _________. (A) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell - the endosymbiont evolved into chloroplasts (B) endosymbiosis of a photosynthetic archaeal cell in a larger bacterial host cell to escape toxic oxygen - the anaerobic archaea evolved into chloroplasts (C) endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell - the endosymbiont evolved into mitochondria (D) evolution of an endomembrane system and subsequent evolution of mitochondria from a portion of the smooth endoplasmic reticulum

13. Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through ________. (A) plasmodesmata (B) tight junctions (C) desmosomes (D) gap junctions

14. Which of the following structures form cytoplasmic channels that connect adjacent plant cells through the cell walls? (A) desmosomes (B) gap junctions (C) plasmodesmata (D) tight junctions

15. The cell walls of bacteria, fungi, and plant cells, and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following characteristics are common to all of these extracellular structures? (A) They must block water and small molecules to regulate the exchange of matter and energy with their environment. (B) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. (C) They are constructed of materials that are synthesized in the cytoplasm and then transported out of the cell for assembly. (D) They are composed of a mixture of lipids and nucleotides.

17. Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to _______. (A) form cleavage furrows during cell division (B) migrate by amoeboid movement (C) separate chromosomes during cell division (D) maintain the shape of the nucleus

18. Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from _______. (A) a bacterium, but not a eukaryote (B) an animal, but not a plant (C) nearly any eukaryotic organism (D) a plant, but not an animal

19. Which cell would be best for studying lysosomes? (A) muscle cells (B) nerve cells (C) endocrine cells (D) phagocytic white blood cells

20. Amoebae move by crawling over a surface (cell crawling), which involves _______. (A) growth of actin filaments to form bulges in the plasma membrane (B) assembly of microtubule extensions that vesicles can follow in the direction of movement (C) reinforcement of the pseudopod with intermediate filaments (D) localized contractions driven by myosin and microtubules

1. You are suffering from Streptococcus throat infection. You share the following with the bacteria that is responsible for your condition.(A)You both belong to the same domain.(B)You both are made up of cells.(C)You both have genetic material in your nucleus.(D) You and Streptococcus have nothing in common.

2. The evolution of one species into two or more species as a result of different populations becoming reproductively isolated from each other is best termed as_________. (A)adaptive radiation (B)creationism (C)natural selection (D) prototype