Question

Spindle fibers are made up of
A) Actin protein and RNA.
B) Cellulose and RNA.
C) Tubulin protein and RNA.
D) Both A and C.

Answer 1

Hint: Spindle fibres are microscopic protein structures that help to separate genetic material during cell division. The spindle fibres are formed by the centrosome, also known as the microtubule-organizing core, or MTOC.

Complete answer:
> Small proteins on the surface of the MTOC are responsible for the lengthening or shortening of the microtubules. These proteins respond to cell signals, and when it is time for cell division, the spindle fibres begin to lengthen. To do this, the alpha-tubulin and beta-tubulin subunits must be added. Together, these two small proteins form a microtubule structure. Many of the individual microtubules together are called spindle fibres.
> The key characteristic of microtubules, and therefore spindle fibres, is that the proteins that regulate microtubules can be expanded or contracted by the addition or removal of tubulin dimers. At first, the MTOCs have to add several of these dimers to the microtubule to expand it around the cell. When the microtubule flies, it finally reaches the chromosome. Special proteins inside the centermer of the chromosome may be bound to the microtubule.
> It forms a protein structure that allows the division of cells. They are also referred to as mitotic spindles. It consists of 97 % of the protein tubulin and 3 % of the RNA. The polymer tubulin is formed by the alpha and beta loops. The chromosomal spindle fibres bind to the kinetochores and isolate the cell.

Thus the correct Answer is Option (C)Tubulin protein and RNA.

Note: The spindle must be distributed evenly between chromosomes in the parent cell and two daughter cells during both forms of nuclear division: mitosis and meiosis.