Multiple Choice
Where do the microtubules of the spindle originate during mitosis in plant and animal cells?
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15. Cytoskeleton and Cell Movement
Microtubules and Cell Division
Multiple Choice
During mitosis, what is the primary role of spindle fibers (microtubules) in the dividing cell?
A
They form the cleavage furrow that pinches the cell into two during cytokinesis.
B
They attach to kinetochores and separate sister chromatids by pulling them toward opposite poles of the cell.
C
They replicate the cell’s DNA to ensure each daughter cell receives a complete genome.
D
They break down the nuclear envelope by enzymatically digesting nuclear lamins.
Verified step by step guidance1
Identify the key structures involved in mitosis, focusing on spindle fibers, which are composed of microtubules.
Understand the function of spindle fibers: they interact with chromosomes during mitosis, specifically at the kinetochores, which are protein complexes on the centromeres of sister chromatids.
Recognize that spindle fibers generate forces to pull sister chromatids apart, ensuring each chromatid moves toward opposite poles of the cell.
Distinguish this role from other processes such as cleavage furrow formation (cytokinesis), DNA replication, and nuclear envelope breakdown, which involve different cellular components and mechanisms.
Conclude that the primary role of spindle fibers during mitosis is to attach to kinetochores and separate sister chromatids by pulling them toward opposite poles, facilitating equal chromosome segregation.
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