Question

The outer and inner membranes of mitochondria are
A) Structurally and functionally similar
B) Structurally and functionally dissimilar
C) Structurally similar and functionally different
D) Structurally different and functionally similar

Answer 1

Hint: Mitochondria contain double layered membranes. The outer layer fully surrounds the inner membrane. A small inter membrane space is present in between the layers. They allow movement of molecules and ions.

Complete Answer:
- Mitochondria are called the powerhouse of the cell. It is a double membrane structure present in the Eukaryotic cells. The membrane of mitochondria is semi permeable in nature to allow the entry and exit of molecules. There are two kinds of membrane present in the mitochondria.
- Outer membrane- It is a phospholipids bilayer which has several integral membrane proteins called the porins. It separates the inside organelle from the rest of the cell. It is 60-75 Angstroms thick. The membrane primary transports nucleotides, ions, and metabolites between cytosol and the intermembrane space. It also associates with the endoplasmic reticulum.
- Inner membrane- The inner membrane has several folds called cristae. It is the site of an electron transport chain and produces ATP. This membrane is permeable to oxygen, carbon dioxide and water only. It acts as an electric insulator and chemical barrier.

Thus the correct answer is B. The membranes of mitochondria are structurally and functionally dissimilar.

Note: The membranes of mitochondria which are totally different to each other. The outer membrane is similar to the plasma membrane in structure. It helps in establishing the connection between the inner mitochondrial and the cytoplasm. The inner membrane is the site for ATP synthesis.