Question

In eukaryotic cells certain organelles, like chloroplasts & mitochondria, have two membranes (an outer and inner membrane) with the inner membrane containing highly involuted or folded structures. What advantages are provided by having two membranes such as those described above? Your answer should focus on form and function seen in these organelles.

Answer 1

Highly folded structures of inner mitochondrial membrane and chloroplast membranes are useful for the increase of surface area to perform tasks in membrane.

Both mitochondrial membrane and chloroplast membranes rely on Electron Transport Chains (ETC) to perform their functions.

In the case of the mitochondria, the Electron Transport Chains (ETC) is found in the inner membrane. It essentially functions to synthesize the energy producing compound ATP.

In the chloroplast, the Electron Transport Chains (ETC) is found in the thylakoid membrane. This is used to produce the necessary reactants for the Calvin cycle and eventually, to yield glucose.

The double membrane structure is necessary in both mitochondria and chloroplast.

In mitochondria The ETS done in between intermembrane space, Inner mitochondrial membrane and mitochondrial matrix

In chloroplast, The ETS done in between Chloroplast stroma and thylakoid membrane.

Mitochondria parts outer to inner

• Outer membrane
• Intermembrane space
• Inner membrane
• matrix

Chloroplast parts outer to inner

• Outer membrane
• Intermembrane space
• Inner membrane
• Thylakoid
• Lumen