Biology Section 7-2

Krebs Cycle

The Krebs cycle is a biochemical pathway that breaks down acetyl CoA, producing CO2, hydrogen atoms, and ATP.

In what part of a mitochondrion does the Krebs cycle occur?

The Krebs cycle occurs in the mitochondrion matrix.

Is cellular respiration more or less efficient than fermentation?

Cellular respiration is more efficient than fermentation.

citric acid

In step 1 , a two-carbon molecule of acetyl CoA combines with a four-carbon compound, oxaloacetic acid, to produce a six-carbon compound, citric acid.

What four-carbon compound is regenerated at the end of the Krebs cycle?

Oxaloacetic acid is regenerated at the end of the Krebs cycle.

What molecule does oxygen become a part of at the end of the electron transport chain?

Oxygen combines with hydrogen to form water.

In what part of a mitochondrion is the electron transport chain located?

The electron transport chain is located in the inner mitochondrial membrane.

List the two processes that together result in cellular respiration.

The first process is glycolysis. The second step is aerobic respiration.

mitochondrial matrix

The mitochondrial matrix is the space inside the inner membrane of a mitochondrion

acetyl CoA

When pyruvic acid enters the mitochondrial matrix, it reacts with a molecule called coenzyme A to form acetyl coenzyme A, abbreviated acetyl CoA.