Question

Murein is found in the cell wall of
A. Diatoms
B. Cyanobacteria
C. Eubacteria
D. Nostoc

Answer 1

Hint: Murein is a type of peptidoglycan that is a polymer made up of amino acids and sugars. These strands are formed by the cross-linking of short peptides that result in the formation of mesh-like polymeric structures that surround the plasma membrane. It is present in true bacteria.

Complete answer: A murein is a polymer of peptidoglycan. It forms a mesh-like network over the plasma membrane of bacteria.
a) Eubacteria – Eubacteria are true bacteria. They are true bacteria because they are the most common form of bacteria that form a major group. The cell wall is made up of peptidoglycan. It consists of amino sugars and amino acids or the murein protein. Murein contains the strands of polyglycan.
b) Diatoms – Diatoms are a group of photosynthetic protists. They are also known as chrysophytes. Diatoms are also called the jewels of the sea. They have a silicated cell wall that is rich in silica. Their cell wall is known as theca.
c) Cyanobacteria – Cyanobacteria is a group of photosynthetic, oxygenic bacteria. Cyanobacteria have the ability to fix nitrogen in special cells known as heterocysts. Their cell wall is made up of peptidoglycan but it does not have murein.
d) Nostoc – Nostoc is a type of cyanobacteria. Cyanobacteria is a group of photosynthetic, oxygenic bacteria. Cyanobacteria have the ability to fix nitrogen in special cells known as heterocysts. Their cell wall is made up of peptidoglycan, but it does not have murein.
Hence, the correct answer is option C.

Note: The lattice structure of peptidoglycan is made up of two amino sugars, NAG (N-acetyl glucosamine) and NAM (N-acetylmuramic acid). Amino sugars are the sugars molecules that have an amine group instead of the hydroxyl groups.