Question

in plant cells, what is responsible for organizing the spindle?
a) centrosomes
b) centrioles
c) microtubules
d) asters
e) centromeres

Explanation:

• Centrosomes: In animal cells, centrosomes (which contain centrioles) organize the spindle. But plant cells lack centrioles.
• Centrioles: Plant cells do not have centrioles.
• Microtubules: Microtubules are part of the spindle fibers. They are organized by structures. In plant cells, microtubule - organizing centers (which can be thought of as analogous to a modified form of what would be centrosomes in animals, but without centrioles) use microtubules to form the spindle.
• Asters: Asters are star - shaped structures around centrosomes in animal cells. Plant cells do not have asters.
• Centromeres: Centromeres are regions on chromosomes where spindle fibers attach. They do not organize the spindle.

Answer:

C. microtubules