Question

Desmosome is a modification of
A. E.R- nucleus complex
B. E.R
C. Golgi complex
D. Plasma membrane

Answer 1

Hint: Cell is the auxiliary and practical unit of life. The plasma membrane implies both to the layer that envelops cells and moreover to the layers that include organelles inside the cell.

Complete answer:
We need to learn that desmosomes are a type of junctional complexes and are also known as Macula adherens. The term ‘desmosome’ was coined by Josef Schaffer in 1920. The word has been derived from a Greek word meaning bond (desmo) and body (soma). They are modified to perform cell-to-cell adhesion. Desmosome is the alteration of the plasma membrane. Desmosome or macula adhaerens is a cell structure which can be characterized as a specific adjustment of cell layer for cell-to-cell attachment. They are intercellular intersections which give solid bonds between cells and furthermore gives mechanical solidarity to tissues.

The middle fiber of the cytoskeleton of contiguous cells is associated with the assistance of desmosomes. They are randomly scattered in the plasma membrane and have a very strong adhesive capacity. They are localized in the tissues that are subjected to intensive stress such as cardiac tissues, bladder as well as gastro-intestinal mucosa. We also need to know that the intermediate filaments present in the desmosome are made up of cadherin, linker and keratin proteins. The length of the extracellular region is 34 nm and contains calcium- binding motifs. The calcium present in the extracellular region helps in forming the cadherin adhesion. They also help the cadherin proteins desmoglein and desmocollin to be rigid and perform adhesion smoothly. Heterophilic interactions bind the cadherin proteins, whereas other cadherin proteins bind through homophilic interactions. Therefore, we can say that desmosomes are the modifications of the plasma membrane. They are concerned with the maintenance of the mechanical integrity of the tissues undergoing stress.

Hence, the correct answer is option (D)

Note: Now, we know that the desmosome is a modification of plasma membrane and is modified to perform cell-to-cell adhesion. They are also known as Macula adherens and have a very strong adhesive capacity. They are composed of certain intermediate filaments that are made up of cadherin, linker and keratin proteins.