Mesosome is a specialized and differentiated form of __________.
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Even though mesosomes are now widely considered artifacts, in the context of most exam questions, you should remember their textbook definition: an infolding of the prokaryotic plasma membrane.
Step 1: Understanding the Concept:
The question asks to identify the cellular structure from which a mesosome is formed in prokaryotic cells. Step 2: Detailed Explanation:
Mesosomes are convoluted infoldings of the plasma membrane (cell membrane) found in many bacteria. They appear as vesicles, tubules, or lamellae within the cytoplasm.
Historically, they were thought to be involved in various functions like cell wall synthesis, DNA replication, cell division (septum formation), and respiration (as an analogue to mitochondrial cristae).
However, strong evidence now suggests that mesosomes are largely artifacts created during the chemical fixation and dehydration process used to prepare bacterial cells for electron microscopy. They are not typically seen in cells prepared by cryofixation.
Regardless of their status as artifacts, for the purpose of a biology question asking about their structural origin, they are defined as being formed from the cell membrane.
Let's examine the options:
(A) Ribosomes: These are separate particles for protein synthesis.
(B) Mitochondria: These are organelles found in eukaryotes, not prokaryotes.
(C) Cell membrane: This is the correct origin. Mesosomes are infoldings of this structure.
(D) Cell wall: This is the rigid layer outside the cell membrane.
Step 3: Final Answer:
A mesosome is a specialized and differentiated form (an infolding) of the prokaryotic cell membrane.
