Question

In which stage of karyokinesis, the spindle fibres start appearing from?
A) Prophase
B) Metaphase
C) Anaphase
D) Telophase

Answer 1

Cell division is the process of dividing cells in different phases. It is of three types; mitosis, meiosis, and binary fission. The eukaryotes undergo mitosis and meiosis cell division that comprises different stages with different phases of division.

Complete answer:
To solve this question, we have to know about mitosis cells division. The mitosis is the nuclear division process in eukaryotic cells that results in the formation of two daughter cells from the parent cell after division. During mitosis there is equal division of the genetic material also takes place. This process comprises five stages; prophase, prometaphase, metaphase, anaphase, and telophase. In prophase, the replicated chromosomes pairs get compact and condense; these paired chromosomes are considered as sister chromatids that attach together by centromeres. Spindle fibers made of microtubule proteins start to appear in this stage that are found in both poles of the cell. In the prometaphase stage, the nuclear envelope that covers the nucleus starts disappearing and the nucleus is no longer separated from the cytoplasm. Kinetochores start to form around the centromeres and the spindle fibers attached to the kinetochores. In metaphase, the microtubules pull the sister chromatids and align them in the equatorial plane. In anaphase, the sister chromatids get separated due to the pulling by the spindle fibers. In this phase, it is being ensured that every daughter cell receives an identical pair of chromosomes. Finally, in telophase, the nuclear membrane appears again around each chromosomal and separates the nucleus from the cytoplasm. Then the chromosome uncoils itself and becomes diffuse and less compact.
Therefore, the stage of karyokinesis, the spindle fibres start appearing is prophase.

Thus, the correct option is ‘A’. Prophase.

Note: Cytokinesis also takes place along with telophase. The cell undergoes separation that divides the cytoplasm of the parental cell into two daughter cells. But in the meiosis process one cell gets divided twice to form four cells.