Q.62 The inner mitochondrial membrane comprises of a series of folds known as
(A) cristae
(B) thylakoids
(C) cisterns
(D) cilia
The inner mitochondrial membrane features distinctive folds called cristae, which increase surface area for ATP production. This structure is crucial for cellular respiration in eukaryotic cells.
Correct Answer
The correct answer is (A) cristae.
Cristae are invaginations or folds in the inner mitochondrial membrane that expand its surface area, hosting electron transport chain complexes and ATP synthase for efficient energy production.
Option Explanations
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(A) Cristae: These are shelf-like folds of the inner mitochondrial membrane, forming tubular or lamellar structures separated by cristae junctions. They maximize space for oxidative phosphorylation, as seen in electron micrographs of mitochondria.
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(B) Thylakoids: Flattened membrane sacs found stacked in chloroplasts’ grana, site of light-dependent photosynthesis reactions, not in mitochondria.
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(C) Cisterns: Flattened membrane disks in the endoplasmic reticulum or Golgi apparatus, involved in protein and lipid processing, unrelated to mitochondria.
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(D) Cilia: Motile hair-like projections on cell surfaces for movement, absent from mitochondrial membranes.
Mitochondrial Structure Overview
Mitochondria possess a double membrane: a smooth outer membrane and a highly folded inner membrane enclosing the matrix. Cristae within the inner membrane house respiratory enzymes, while the matrix contains TCA cycle components.
This design supports high ATP yield, vital for energy-demanding cells like muscle or neurons. More cristae correlate with greater metabolic activity.
