Prokaryotic & Eukaryotic Cells - NEET Biology Class 11 Free MCQ Practice

Prokaryotic cell is usually small (0.1-5.1μm) in size whereas eukaryotic cell size is comparatively larger (5-100μm). Prokaryotic cells multiply very rapidly by asexual means like binary fission, sporulation etc.

Topic in NCERT: PROKARYOTIC CELLS

Line in NCERT: "They are generally smaller and multiply more rapidly than the eukaryotic cells."

Correct option: B - (ii) and (iii).

Mesosomes are infoldings of the plasma membrane found in prokaryotic cells only; they are not present in eukaryotic cells.

They are formed by extensions of the plasma membrane into the cytoplasm and may appear as vesicles, tubules or lamellae. These structures increase the surface area of the membrane, which helps membrane-bound processes.

Mesosomes assist in cell wall formation, play a role in DNA replication and distribution to daughter cells, and provide sites for enzymatic activities involved in respiration. Therefore statements (ii) and (iii) are correct while statement (i) is incorrect.

Glycocalyx (mucilage sheath) is the outermost layer of the bacterial cell envelope which consists of non-cellulosic polysaccharides with or without proteins. It may occur in the form of loose sheath, called slime layer. If it is a thick covering, it is called capsule. Glycocalyx gives sticky character to the cell and is not absolutely essential for survival of bacteria. It prevents desiccation, protects from phagocytes, toxic chemicals and viruses and serves in attachment. It may give selective advantage though in certain situations.

Topic in NCERT: Cell Envelope and Modifications

Line in NCERT: "Glycocalyx differs in composition and thickness among different bacteria. It could be a loose sheath called the slime layer in some, while in others it may be thick and tough, called the capsule."

Option C is correct.

Glycocalyx (capsule or slime layer) is the outermost layer in many bacteria; it is mainly composed of polysaccharides and sometimes proteins.

The cell wall lies internal to the glycocalyx and, in bacteria, is composed of peptidoglycan which provides shape and rigidity.

The innermost layer is the plasma membrane (cell membrane), a lipid bilayer that regulates transport of substances into and out of the cell.

Therefore the correct outward-to-inward sequence is Glycocalyx → Cell wall → Cell membrane, matching option C.

Plasmid is a structure in bacterial cell consisting of DNA that can exist and replicate independently of the chromosome. Plasmids provide genetic instructions for certain cell activities (e.g., antibiotic resistance). They can be transferred from cell to cell in a bacterial colony.

Topic in NCERT: PROKARYOTIC CELLS

Line in NCERT: "In addition to the genomic DNA (the single chromosome/circular DNA), many bacteria have small circular DNA outside the genomic DNA. These smaller DNA are called plasmids."

The cytoplasmic ribosomes of prokaryotes (blue green algae, bacteria and PPLOs) are 70S. They have two subunits 50S and 30S.