Question

what is the final result of cytokinesis in mitosis?
a. two genetically identical daughter cells are formed.
b. chromosomes become visible.
c. spindle fibers begin to form.
d. the cell membrane dissolves.

what role do spindle fibers play in mitosis?
a. they condense chromatin into chromosomes.
b. they regulate the movement of water into the cell.
c. they form the cell membrane.
d. they pull sister chromatids apart to opposite poles of the cell

Explanation:

• For the first question:
• In mitosis, cytokinesis is the final step. Its main purpose is to divide the cytoplasm and organelles, resulting in two daughter cells. Since mitosis is a process of asexual reproduction (in terms of cell - division for growth, repair etc. in multicellular organisms and asexual reproduction in some unicellular organisms) where the genetic material is replicated and then equally distributed. So, two genetically identical daughter cells are formed.
• Chromosomes becoming visible (option b) occurs in prophase. Spindle fibers beginning to form (option c) also occurs in prophase. The cell membrane does not dissolve (option d) during normal mitosis.
• For the second question:
• Spindle fibers are made of microtubules. Their main function in mitosis is to attach to the kinetochores of sister chromatids and pull them apart to opposite poles of the cell during anaphase.
• Condensing chromatin into chromosomes (option a) is mainly the role of histone proteins and the process of chromosome condensation in prophase. Regulating water movement (option b) is the role of membrane - transport proteins. Forming the cell membrane (option c) is not the function of spindle fibers.

Answer:

• First question: a. Two genetically identical daughter cells are formed.
• Second question: d. They pull sister chromatids apart to opposite poles of the cell.