Question

Each chromonemata contains
A.Single DNA molecule
B.Double DNA molecule
C.3 DNA molecule
D.No DNA molecule

Answer 1

The nucleus of the cell contains genetic material within chromosomes. Chromosomes are tightly coiled thread-like structures that are made up of protein and a single molecule of DNA. They undergo cell division and show condensed form called chromatin during metaphase, which is then visible under the light microscope. Each chromosome consists of three parts- pellicle, matric, and chromonemata. The pellicle is the outer envelope of the chromosome. Matrix is the ground substance in which chromonemata is present. Chromonema is a spirally coiled, fiber-like structure in the central filament that is the primary form of chromosome condensation.

Complete step by step answer: -Single DNA molecule
Each chromonema consists of microfibrils that are made up of a single molecule of DNA, that is embedded in the matrix of chromosomes.
Double DNA molecule: Two chromonemata consist of two DNA molecules.
3 DNA molecules: Three chromonemata consist of three DNA molecules.
No DNA molecule: Genetic material is always composed of DNA molecules. Even cellular organelles present within the cells like mitochondria and plasmid contain DNA molecules.
Thus, the correct option is option A- Single DNA molecule.

Note: Human body consists of 23 pairs of chromosomes i.e. 46 chromosomes in total. 22 pairs of chromosomes present are called autosomes while the remaining one pair is sex chromosome - X and Y. These sets of chromosomes are passed on in the form of genetic material from parents to offspring along with sex chromosome thus determining the gender of the offspring. Other structures present on chromosomes are chromatid, chromomeres, centromere, secondary constriction, satellite, and telomere.