Use the following information when answering the corresponding questions).
The mechanism of cell crawling in protist species is not well defined. The textbook states that pseudopodia extension involves interactions between actin and myosin the same molecules that are involved in mammalian muscle contraction). However, p the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawlin protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in severa of protist, but physiological studies had failed to show a functional link between actin, myosin, and cell crawling.
In a study by N. Poulsen et al. Diatom gliding is the result of an actin- myosin motility system, Cell Motility and the Cytoskeleto 1999):23- 22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.
Figure 27.3
-The data graphed in Figure 27.3 could be an artifact if latrunculin A kills this species of diatoms i.e., that may be why the cells are not moving). Which of the following would be the best evidence that latrunculin A is not killing the cells?
A) There were still a small percentage of motile cells in the culture treated with the toxin.
B) When the toxin was washed off the culture, the cells began to move again.
C) Most of the cells in the control were moving, indicating that they were alive.
D) When the toxin was applied to another species of diatom, 25% of them continued to move.

Question

Use the following information when answering the corresponding questions).
The mechanism of cell crawling in protist species is not well defined. The textbook states that pseudopodia extension involves interactions between actin and myosin the same molecules that are involved in mammalian muscle contraction). However, p the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawlin protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in severa of protist, but physiological studies had failed to show a functional link between actin, myosin, and cell crawling.
In a study by N. Poulsen et al. Diatom gliding is the result of an actin- myosin motility system, Cell Motility and the Cytoskeleto 1999):23- 22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.
  Figure 27.3
-The data graphed in Figure 27.3 could be an artifact if latrunculin A kills this species of diatoms i.e., that may be why the cells are not moving). Which of the following would be the best evidence that latrunculin A is not killing the cells?
A) There were still a small percentage of motile cells in the culture treated with the toxin. 
B) When the toxin was washed off the culture, the cells began to move again. 
C) Most of the cells in the control were moving, indicating that they were alive. 
D) When the toxin was applied to another species of diatom, 25% of them continued to move.

Quizplus · Accepted Answer

If the cells begin to move again after the toxin is washed off, it suggests that the toxin is not killing the cells but rather inhibiting their motility. Option A is not ideal because it is possible that the small percentage of motile cells is due to individual variability or resistance to the toxin rather than evidence that the toxin is not killing the cells. Option C is not relevant to determining if the toxin is killing the cells because it refers to the control group, not the experimental group. Option D is also not ideal because it refers to a different species of diatom and may not be generalizable to the species being studied.

Use the Following Information When Answering the Corresponding Questions)