Question

Which of the following is/are active transport mechanism(s) in prokaryotes where the substance is chemically altered during transport across the membrane?

• A. ( Group translocation )
• B. ( Simple diffusion )
• C. ( Facilitated diffusion )
• D. ( Osmosis )

Hint:

Understanding different transport mechanisms is crucial in microbiology, as it helps explain how cells adapt to nutrient availability and maintain internal environments.

Answer 1

The Correct Option is A

Active transport mechanisms are crucial for the uptake of nutrients and other molecules in cells, especially in environments where concentration gradients do not favor passive transport. Analysis of Each Option: (A) Group translocation: Correct. This is a type of active transport unique to prokaryotes, such as the phosphoenolpyruvate:sugar phosphotransferase system (PTS). In this system, a substance is chemically modified during its transport across the cell membrane, typically by phosphorylation. This method not only moves the substance against a concentration gradient but also modifies it to keep it inside the cell. (B) Simple diffusion: Involves the movement of substances from an area of higher concentration to an area of lower concentration, not requiring energy and not involving chemical modification. (C) Facilitated diffusion: Also a passive transport mechanism, using carrier proteins to speed the movement of molecules across the membrane without energy expenditure or chemical alteration. (D) Osmosis: The movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. It does not involve the chemical alteration of the water molecules. Conclusion:
Explanation: Group translocation is the only option listed that involves both active transport and chemical modification of the transported substance, making it essential for cellular metabolism and internal regulation in prokaryotes.