Question

Membranes must be filled with fluid to function properly(as you learned in Concept 7.1). How does the operation of the electron transport chain support that assertion?

Short answer

The membranes must be filled with fluid to make the transport efficient. In the electron transport chain, substances such as ubiquinone Q are transported freely via the membrane due to the presence of fluid.

Step-by-step solution

Description of membrane and its fluidity 

The cell membrane is the way or barrier for the substance to pass through it. The cholesterol content in the cell and fatty acid is responsible for the fluidity of the membrane. The membrane fluidity helps the transport of proteins via the membrane.

Electron transport chain

The electron transport chain is the phase in oxidative phosphorylation. The main work of this process is to create the electrons that are required for ATP synthesis.

The electron transport chain occurs in the mitochondria. The precursor required for this process moves from the cytoplasm into the mitochondria to carry out the electron transport chain process.

Membrane fluidity

Membrane fluidity is responsible for the transport of substances such as ubiquinone. The fluidity of the membrane facilitates the movement of substances across the membrane.

If the membrane is very rigid, then the passage of the substance will not take place. Then, the series of reactions taking place in the oxidative phosphorylation will be interrupted.

Hence, the fluidity of the cell membrane is responsible for the movement of ubiquinone Q that participates in the electron transport chain.