Test: Prokaryotic Cells

Correct Answer :- d

Explanation : Both prokaryotic and eukaryotic cells have structures in common. All cells have a plasma membrane, ribosomes, cytoplasm, and DNA. The plasma membrane, or cell membrane, is the phospholipid layer that surrounds the cell and protects it from the outside environment. Ribosomes are the non-membrane bound organelles where proteins are made, a process called protein synthesis. The cytoplasm is all the contents of the cell inside the cell membrane, not including the nucleus.

Prokaryotic cells are cells that do not have a true nucleus or most other cell organelles. Organisms that have prokaryotic cells are unicellular and called prokaryotes. Bacteria and archaea are prokaryotes.

Nostoc is a prokaryote. Prokaryotic cells lack membrane bound organelles and well organized nucleus, that is nuclear envelope is absent in these cells.

The nuclear envelope, also known as the nuclear membrane, a bilayer membrane which surrounds the nucleus, and in eukaryotic cells it encases the genetic material.

Prokaryotes lack nucleus. In prokaryotes DNA is present as nucleoid. Prokaryotes lack membrane bound organelles.

The distinction is that eukaryotic cells have a "true" nucleus containing their DNA, whereas prokaryotic cells do not have a nucleus.

Similar to the cytoplasm of a cell (protoplasm), the nucleus contains 'nucleoplasm' (nucleus sap) or karyoplasm. The nucleoplasm is one of the types of protoplasm, and it is enveloped by the nuclear membrane or nuclear envelope. The nucleoplasm includes the chromosomes and nucleoli.

As in prokaryotes, centrioles are absent and centrioles play an important part in mitosis during spindle fibre formation. so mitosis is not seen in them, thus they use binary fission.

50S, roughly equivalent to the 60S ribosomal subunit in eukaryotic cells, is the larger subunit of the 70S ribosome of prokaryotes. The 50S subunit is primarily composed of proteins but also contains single-stranded RNA known as ribosomal RNA (rRNA).

The plasma membrane of eubacteria resembles that of the eukaryotic cell. It is made of phospholipid, protein and some amount of polysaccharides. However, it lacks sterol, the characteristic of the eukaryotic cell membrane. Instead, there is sterol like hopanoid.

The correct option is Option C.

Glycocalyx or pericellular matrix is a carbohydrate-enriched coating of glycoprotein and a glycolipid that covers the cell membranes of a few bacteria, epithelial cells and other cells. 

It is mainly used in the recognition of the cell and also regulates the endothelial vascular tissues.

So, the correct answer is 'Plasma membrane'.