The figure below shows the structure of a mitochondrion with its four parts labelled (A), (B), (C) and (D). Select the part correctly matched with its function. [Figure]
- Part (B) : Inner membrane – forms infoldings called cristae
- Part (C) : Cristae – possess single circular DNA molecule and ribosomes
- Part (A) : Matrix – major site for respiratory chain enzymes
- Part (D) : Outer membrane – gives rise to inner membrane by splitting
Answer
(1) Part (B) : Inner membrane – forms infoldings called cristae
Solution
As per NCERT, the inner membrane of mitochondrion forms a number of infoldings called the cristae towards the matrix; the cristae increase the surface area.
The matrix (not the cristae) possesses a single circular DNA molecule, a few RNA molecules and ribosomes (70S).
Enzymes of the respiratory chain (electron transport system) are located on the inner membrane (cristae), not in the matrix.
The outer and inner membranes are separate membranes; the outer membrane does not give rise to the inner membrane by splitting.
∴ Part (B) : Inner membrane – forms infoldings called cristae is correctly matched.
Answer: (1)