Question

What is true about the genetic material of a prokaryotic cell?
A. Lacks histones
B. Not enveloped by nuclear membrane
C. Composed of a single circular DNA molecule
D. All of these

Answer 1

Hint: The genetic material of prokaryotes, consists of a single circular DNA molecule lying entangled in a nucleoid. The nuclear membrane is absent in prokaryotes. Histones are water-soluble proteins that help in DNA packaging in chromosomes. Prokaryotic cells lack histone proteins.

Complete answer:
Genetic material of prokaryotic cells is carried on a single circular of DNA which is attached to the cell membrane and in direct contact with the cytoplasm. There is no envelope membrane, so there is no true nucleus, and prokaryotes lack histone protein but simply a prokaryotic DNA known as a nucleoid.
In prokaryotic cells which lack a nucleus and other organelles. The bacteria and the archaea are groups of prokaryotes, mostly prokaryotes are small, single-celled organisms that have a relatively simple structure. In Prokaryotic cells absent nuclear membrane but they are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm.
In eukaryotes, the presence of a nucleus and other membrane-bound organelles differentiates prokaryotes.

Hence, the correct answer is option (D).

Additional information: In prokaryotes they carry a small amount of genetic material in the form of a single molecule, or chromosome, of circular DNA. the nucleoid, which is not surrounded by a nuclear membrane. Many prokaryotes also carry small, circular DNA molecules called plasmids, which are distinct from the chromosomal DNA and can provide genetic material.

Note: The cell walls of a prokaryote acts as an extra layer of protection, helps maintain cell shape, and prevents dehydration. Small size of prokaryotes allows quick entry of ions and molecules to other parts of the cell.