2. Cell Chemistry & Cell Components

How does the hydrolysis of ATP result in the movement of a motor protein along a cytoskeletal filament?

Microtubules often produce movement through their interaction with motor proteins. But in some cases, microtubules move cell components when the length of the microtubule changes. Through a series of experiments, researchers determined that microtubules grow and shorten as tubulin proteins are added or removed from their ends. Other experiments showed that microtubules make up the spindle apparatus that 'pulls' chromosomes toward opposite ends (poles) of a dividing cell. The figures below describe a clever experiment done in 1987 to determine whether a spindle microtubule shortens (depolymerizes) at the end holding a chromosome or at the pole end of a dividing cell. Experimenters labeled the microtubules of a dividing cell from a pig kidney with a yellow fluorescent dye. As shown on the left half of the diagram below, they then marked a region halfway along the microtubules by using a laser to eliminate the fluorescence from that region. They did not mark the other side of the spindle (right side of the figure).

Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?

Which of the following is true for microfilaments?

Which of the following structures has a 9 + 2 arrangement of microtubules?

Which of the following structures is not composed of microtubules?

The figure below illustrates the results they observed as the chromosomes moved toward the opposite poles of the cell. Describe these results. What would you conclude about where the microtubules depolymerize from comparing the length of the microtubules on either side of the mark? How could the experimenters determine whether this is the mechanism of chromosome movement in all cells?

Microtubules and microfilaments commonly work with which of the following to perform many of their functions?

The eukaryotic cytoskeleton is a highly dynamic network of filaments and motor proteins. Which of the following correctly describe activities of these cytoskeletal components? Select True or False for each statement.T/FMyosin motors walk toward the plus ends of intermediate filaments.T/FDynein motors are responsible for the whip-like movement of eukaryotic flagella.T/FKinesin motors move vesicles along tracks toward the microtubule-organizing center.T/FActin filaments are required for cytoplasmic streaming.

Which of the following is not a component of the cytoskeleton?

Which of the following structures is found in animal cells but not in plant cells?

Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?