2. Cell Chemistry & Cell Components

Introduction to the Cytoskeleton

Open Question
Mark the following statements about the cytoskeleton as true or false. If a statement is false, correct it to make a true statement.

f. Endocytosis, exocytosis, muscle cell contraction, and cellular 'crawling' are all mediated by intermediate filaments.
Multiple Choice
What component of the cytoskeletons do motor proteins use to transport vesicles?
Multiple Choice
In human cells, ___________________ are used to move a cell within its environment while ___________________ are used to move objects in the environment relative to the cell.
Multiple Choice
Microtubules and microfilaments commonly work with which of the following to perform many of their functions?
Multiple Choice
Which statement about the cytoskeleton is true?
Multiple Choice
Which of the following structures is found in animal cells but not in plant cells?
Multiple Choice
Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?
Multiple Choice
Basal bodies are most closely associated with which of the following cell components?
Open Question
What effect would the hypothetical poison of question 3 have on other functions of the cell? Explain.
Open Question
How does the hydrolysis of ATP result in the movement of a motor protein along a cytoskeletal filament?
Open Question
Describe two different ways in which cilia can function in organisms.
Open Question
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.
Open Question
George Palade's research group used the pulse–chase assay to elucidate the secretory pathway in pancreatic cells. If they had instead performed this assay on muscle cells, where would you expect the labeled proteins to end up during the chase? (Muscle cells consist primarily of actin and myosin filaments and have high energy demands for muscle contraction.)
Open Question
Cilia are found on cells in almost every organ of the human body, and the malfunction of cilia is involved in several human disorders. During embryological development, for example, cilia generate a leftward flow of fluid that initiates the left-right organization of the body organs. Some individuals with primary ciliary dyskinesia exhibit a condition (situs inversus) in which internal organs such as the heart are on the wrong side of the body. Explain why this reversed arrangement may be a symptom of PCD.
Open Question
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?