Question

Position of the same arm of chromosomes during metaphase of mitosis are
(a)Towards the equator
(b)Poleward
(c)At any place in the spindle
(d)Variable from plant to plant

Answer 1

Hint Mitosis is known as equational division as the chromosome number remains the same after the division. It takes place in the body in order to increase the number of cells resulting in growth. Chromosomes are arranged on the equator during the metaphase of mitosis.

Complete Answer:
Metaphase is that phase of the cell division in which the condensation of the chromosomes is complete and thus it is best observed under the microscope. During metaphase of mitosis, chromosomes are arranged at the equator and each chromatid of the chromosome is attached to spindle fibers by its kinetochore. This arrangement is known as the metaphase plate. At this stage, the arms of the chromosomes are variably oriented and thus can be at any place. But there is a specific direction during anaphase in which the arms are pointed towards the equator and the centromere is towards the pole.

Additional information:
Prophase: It is the first stage of mitosis and is marked by the initiation of condensation of the chromosomes. Centrosomes begin to move towards the poles and radiate out aster rays. Cell organelles and nuclear envelope disappear at the end of this stage.
Metaphase: The key features of this stage include the attachment of spindle fibers to the kinetochores of the chromosomes and the arrangement of chromosomes at the equator.
Anaphase: Each chromosome arranged at the equator is simultaneously split into daughter chromatids due to the contraction of the spindle fibers. This is followed by each chromatid being pulled towards the opposite poles by the spindle fibers.
Telophase: Chromatids at the poles decondense and nuclear envelope along with cell organelles reappear.

So, the correct option is ‘At any place in the spindle’.

Note:
-Telophase is followed by karyokinesis (nuclear division) and cytokinesis (cell division).
-In animal cells, cytokinesis takes place by furrow formation in the plasma membrane whereas in plant cells there is cell plate formation which later becomes the middle lamella.
-Meiosis is known as reductional division because the chromosome number becomes half after the division.