Question

The figure above shows the structure of a mitochondrion with its four parts labeled (A), (B), (C) and (D). Select the part correctly matched with its function.

• A. Part (D): Outer membrane - gives rise to inner membrane by splitting
• B. Part (B): Inner membrane - forms infoldings called cristae
• C. Part (C): Cristae - possess single circular DNA molecule and ribosomes
• D. Part (A): Matrix - major site for respiratory chain enzymes

Answer 1

The correct option is B Part (B): Inner membrane - forms infoldings called cristae

The mitochondria is an oval shaped double membrane-bounded organelle. The outer membrane (D) is continuous while the inner membrane (B) folds to form finger-like projections called cristae. The folding of the inner membrane increases the surface area inside the organelle, the increased surface area creates more space for reactions to occur. The fluid contained in the mitochondria is called the matrix. It is the space enclosed by the inner membrane. It is important in the production of ATP with the aid of the ATP synthase contained in the inner membrane. Thus, option B is correct.