Question

Outer and inner membranes of mitochondria are

• A. Structurally and functionally similar
• B. Structurally and functionally dissimilar
• C. Structurally similar but functionally different
• D. Structurally different but functionally similar

Answer 1

Answer: (B)

Structurally and functionally dissimilar

• The mitochondria is a double-membraned cell organelle, known as the powerhouse of the cell which is present in all eukaryotic cells.
  
• It has an outer membrane and an inner membrane.

1) The inner mitochondrial membrane has folds called cristae which helps in increasing the surface area.

• The enzyme ATP synthase is embedded in the inner mitochondrial membrane helps in the synthesis of ATP molecule (energy currency of the cell).
• It is also the site of the electron transport chain (aerobic respiration).

2) The outer mitochondria membrane is a phospholipid bilayer embedded with integral proteins.

• This layer contains porins that allow the movement of molecules across them(10,000 Daltons or less).
• It is permeable to water, ions and few proteins to move freely into the inter mitochondrial space.
  
• So, the correct answer is 'Structurally and functionally dissimilar'.