What is the structure that directs chromosome movement during mitosis and aids in the formation of the microtubule scaffolding that pulls on the chromosomes?
a. Centrosome (maybe)
b. Nucleosome (don't think so)
c. Spindle (maybe)
d. Cytokinesis(don't think so)
The correct answer is c. Spindle. The spindle is a structure that forms during mitosis and plays a crucial role in directing the movement of chromosomes and the formation of the microtubule scaffolding that pulls on the chromosomes. To arrive at this answer, let's break down the question and evaluate each option:
a. Centrosome: While the centrosome is involved in spindle formation, it is not directly responsible for directing chromosome movement or aiding in the formation of the microtubule scaffolding. Therefore, this is not the correct answer.
b. Nucleosome: Nucleosomes are units of DNA packaging, consisting of DNA wound around histone proteins. They are not directly involved in mitosis or chromosome movement. Hence, this is not the correct answer.
c. Spindle: The spindle is a structure composed of microtubules that forms during mitosis. It interacts with the chromosomes, facilitating their movement and separation during cell division. The microtubules of the spindle attach to the kinetochores of the chromosomes and exert forces that contribute to the process of chromosome movement and positioning. Thus, this is the correct answer.
d. Cytokinesis: Cytokinesis, the division of the cytoplasm, occurs after mitosis and is not responsible for directing chromosome movement or aiding in the formation of the microtubule scaffolding. Therefore, this is not the correct answer.
Therefore, the correct answer is c. Spindle.