Question

when animal cells undergo cell division, several cellular structures aid the the movement of chromosomes into the two new daughter cells. what are these cellular structures?
a dna and the resulting transcribed rna.
b nucleolus and the proteins it produces.
c centrioles and the spindle fibers they produce.
d smooth er and the proteins produced and packaged there.

(images: dna replication, mitosis stages with chromosomes)

Explanation:

To determine the correct answer, we analyze each option:

• Option A: DNA replication and RNA transcription are for genetic information processing, not chromosome movement in cell division.
• Option B: The nucleolus produces ribosomal RNA and ribosomal proteins, not structures for chromosome movement.
• Option C: Centrioles in animal cells form spindle fibers during mitosis. Spindle fibers attach to chromosomes and pull them to opposite poles, aiding their movement into daughter cells.
• Option D: Smooth ER is involved in lipid synthesis and detoxification, not chromosome movement.

Thus, centrioles and spindle fibers (Option C) are responsible for chromosome movement in cell division.

Answer:

C. Centrioles and the spindle fibers they produce.