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Question #46756

Difficulty: 8/10 | 🟢 Free

The Question

According to the chemiosmotic hypothesis, ATP synthesis requires a membrane, a proton pump, a proton gradient, and ATP synthase. While prokaryotes like Cyanobacteria successfully perform photophosphorylation, Mycoplasma cannot. Which of the following structural constraints fundamentally prevents Mycoplasma from establishing a light-driven electrochemical gradient?

Options

  • A.

    The absence of a rigid cell wall, which is required to maintain the high osmotic pressure generated by proton accumulation.

  • B.

    The inability to develop specialized intracellular membrane invaginations required for lumenal proton sequestration.

  • C.

    The complete lack of a phospholipid bilayer, which prevents the embedding of the F0-F1 ATP synthase complex.

  • D.

    The absence of double-membrane bound organelles like chloroplasts to house the electron transport chain.

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Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Evolutionary_Exception

Tackle problems where standard rules evolve or change based on specific environmental constraints.

Concepts Behind This Question

Thylakoid Lumen Sequestration|Cell Cycle and Cell Division|Mycoplasma

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Students often memorize that Mycoplasma lacks a cell wall but fail to connect this simplified structural organization to physiological limitations, such as the inability to form internal membrane compartments (chromatophores/thylakoids) necessary for chemiosmosis.

The trap in Option D exploits the common misconception of conflating the requirement of membrane-bound organelles (chloroplasts) with membrane invaginations (thylakoids in prokaryotes).

Quick Facts About This Question

Question Information

SubjectBiology
ChapterCell – The Unit of Life - Class 11
ConceptThylakoid Lumen Sequestration
Difficulty8
Cognitive Load5
Target Solve Time120 sec
AccessFree