Final answer:
The claim that the mitotic spindle is composed of actin and myosin filaments is false; instead, it's composed of microtubules made of tubulin proteins. Actin and myosin are involved in muscle contraction and other cellular motions, but not in forming the mitotic spindle. The spindle fibers originate from the centrosome and attach to kinetochores during prometaphase of mitosis.
Step-by-step explanation:
The statement that mitotic spindle is composed of actin filaments and myosin filaments is false. The mitotic spindle fibers are indeed composed of microtubules, which are polymers of the protein tubulin. Microtubules form two kinds of spindle fibers within the spindle apparatus: kinetochore microtubules, which attach to the kinetochore of the chromosomes and are responsible for moving the chromosomes during mitosis, and non-kinetochore microtubules, which interact with those from the opposite pole of the spindle. Actin and myosin, on the other hand, are involved in muscle contraction and do not form the mitotic spindle.
During cell division, actin filaments may assist in the process, such as by interacting with myosin for cytokinesis in eukaryotic cell division or by facilitating cellular events requiring motion. However, they do not make up the mitotic spindle structure. Therefore, the specific components of the mitotic spindle apparatus critical for eukaryotic cell division are microtubules, not actin or myosin. The mitotic spindles originate from the centrosome, not the kinetochore, centromere, or cleavage furrow.
During the stages of mitosis, attachment of mitotic spindle fibers to the kinetochores is particularly characteristic of prometaphase, following the breakdown of the nuclear envelope in prophase, and before the alignment of chromosomes at the metaphase plate.