Cellular and Molecular Biology

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Mitochondria: Pyruvate and the Citric Acid Cycle


The mitochondria are often referred to as the power plants of the cell.

Mitochondria import the molecule pyruvate and use the citric acid cycle to convert pyruvate into acetyl-CoA, essentially using pyruvate as 'fuel', for further steps that generate high-energy electron carriers $NADH$ and $FAD{ H }_{ 2 }$.

These molecules are used to pass their high-energy electrons through the mitochondria’s electron transport chain that generates the majority of the cell’s ATP, which is the ultimate energy source that powers most of the cell’s functions.

Using your knowledge of the cell’s mechanisms for processing energy, choose the BEST answers for where the pyruvate comes from.

Select ALL that apply.


Carbon dioxide by direct diffusion into the mitochondria (in plants).


Carbohydrates produced in the chloroplasts (in plants).


Carbohydrates from resources (food) external to the cell (in non-plants).


Lipids from resources (food) external to the cell (in non-plants).