Question

Are centrioles found in prokaryotic cells?

Answer 1

Hint: Prokaryotic cells are the primitive one and their genetic material isn't enveloped by a nuclear membrane. In addition, the prokaryotic cells have extra genomic material other than the genetic material. This smaller DNA is called plasmids. These plasmids have unique phenotypic character, which provide the bacteria resistance against antibiotics. There are no organelles found in prokaryotic cells except ribosomes. Prokaryotes have something unique in the form of inclusions.

Complete answer:
Prokaryotic cells are represented by bacteria, blue-green algae, mycoplasma and PPLO. They are generally smaller and multiply more rapidly than the eukaryotic cells. They vary in size. The four basic shapes of bacteria are bacillus, coccus, vibrio, and spirillum. They don’t have well-defined nuclei. They don’t have any cell organelles(endoplasmic reticulum, Golgi apparatus etc.)except ribosomes. They have specialised differentiated form of cell membrane called mesosome which is the characteristic of prokaryotes. They are essentially infolding of cell membranes.
Most prokaryotic cells have chemically complex cell envelopes. The cell envelope consists of a tightly bound three layered structure glycocalyx cell wall and plasma membrane. Bacteria can be classified into two groups on the basis of the differences in the cell envelope and membrane in which they respond to the staining procedure developed by Gram viz. Those that take up the gram stain are Gram positive and others that do not are Gram negative bacteria. That means, the Prokaryotic cells don't have a centriole because prokaryotic cells have naked genetic material, not enveloped by the nuclear membrane. Centrosome is an organelle usually containing two cylindrical structures called centrioles. Centriole is needed to separate the chromosome during anaphase phase of mitosis. This is the characteristic feature of the eukaryotic cell. There are two centrioles in the cell of eukaryotes, it doubles during the synthesis phase (S- phase). So, both the centrioles in centrosome lie perpendicular to each other in which each has an organization like the cartwheel. It consists of nine evenly spaced peripheral fibrils of tubulin protein.

Note:
Centrioles form the basal body of cilia or flagella, and spindle fibres that give rise to spindle apparatus during cell division in animal cells. The prokaryotic cells have ribosomes which are 70s while eukaryotic cell ribosomes are 80s. Ribosomes are sites for polypeptide or protein synthesis and therefore, act as protein factories.