Question

True chromosomes absent in prokaryotes due to the absence of
A. Nucleus
B. Nucleolus
C. Histone
D. All of the above

Answer 1

Hint: Chromosomes are structures present in cells, through which the characters are passed onto the next generation through reproduction. True chromosomes are only present in eukaryotic cells, where a proper nuclear arrangement is present.

Complete answer:
Alkaline proteins that are found in the nucleus of eukaryotic cells are known as histones. It helps in arranging the DNA strand, by wrapping the DNA around histone molecules. The arrangement is known as a nucleosome. These structures play a major role in gene regulation. In prokaryotic cells, there is an absence of a well-organized nucleus. Since histone proteins are absent in prokaryotes, there is an absence of true chromosomes. Since prokaryotes such as bacteria contain a circular DNA instead of chromosomes. The presence of true chromosomes can be seen in eukaryotic cells such as plants and animal cells.
i. A well-defined nucleus is absent in prokaryotic cells. They possess a region in the cytoplasm called the nucleoid where the genetic material is present.
ii. Nucleolus is a structure present within the nucleus of eukaryotic cells. The site consists of proteins and RNA.
Hence, the correct answer is option C.

Additional information: Histones are proteins that play an important role in the DNA condensation process. It is an octamer made up of two molecules of H2A, H2B, H3 and H4.

Note: Prokaryotic cells differ from eukaryotic cells in size and cell organelles. The size of prokaryotic cells is smaller than eukaryotic cells. Important cell organelles such as mitochondria, endoplasmic reticulum, chloroplasts, Golgi bodies, etc are present only in eukaryotes.