Question

In which stage of cell division, division of matrix of chromosome occurs?
A)Late prophase
B)Early metaphase
C)Late metaphase
D)Anaphase

Answer 1

Matrix is the material or tissue which is seen in between a eukaryotic organisms cell. Each chromosome is bounded by a membrane called pellicle.

Complete answer:
It is very thin and is formed of achromatic substance. This membrane encloses a jelly-like substance which is usually called matrix. In the matrix is present the chromonemata. The matrix is also formed of achromatic or nongenic material.
The presence of matrix is controversial but in one organism, Luzula campestris (Woodrush), a plant belonging to the family Juncaceae, its existence is clearly indicated. Recently by the electron microscopic study of the chromosome the presence of pellicle and matrix between the coils of chromonema has been rejected (Darlington, 1937; Ris, 1945).
The function and structure of the matrix is not known. Presumably it aids in keeping the chromonemata within bounds so that the manoeuvres of the chromosome during cell division can take place unhindered. It may also serve as an insulating sheath for the genes during cell division.

Chromonemata: Within the matrix of each chromosome are found embedded two identical, spirally coiled threads, the chromonemata or chromonematal fibrils. Both the chromonemata are so tightly coiled that they appear as a single thread of about 800 A thickness.
At metaphase each chromosome consists of two symmetrical structures, the chromatids, each of which contains a single DNA molecule. The chromatids are attached to each other only by the centromere and become separated at the start of anaphase, when sister chromatids migrate to opposite poles.

Throughout late metaphase, a chromosome composed of two chromatids is attached together by the centromere, and will get arranged at the equatorial plate. The spindle fibres contract by separating each chromosome into its two chromatids, or single chromosomes. Each pair of chromatids goes to both of the two new cells that form. As a result if the cell have four double chromosomes prior to metaphase, the new cells will each have four single chromosomes. The number of chromosomes remains unaffected and the double chromosomes have easily become single chromosomes.

Hence, the correct answer is option (C)

Note: The matrix generally contains deoxyribonucleic acid of the mitochondrial genome and also the enzyme of the tricarboxylic acid known as the citric acid cycle.