Definition: Citric acid cycle - A series of chemical reactions in cellular respiration that generates electron carriers and carbon dioxide from the breakdown of acetyl groups.

Highlight: The citric acid cycle is an aerobic process, occurring only in the presence of oxygen.

Vocabulary: Oxaloacetate - A four-carbon molecule that combines with the acetyl group to initiate the citric acid cycle.

Definition: Glycolysis - The metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH.

Example: In the Energy Pay-off stage, 4 ATP molecules are produced per glucose molecule, resulting in a net gain of 2 ATP molecules after subtracting the 2 ATP used in the Energy Investment stage.

Highlight: Glycolysis can occur in both the presence and absence of oxygen, making it a versatile energy-producing pathway for cells.

Vocabulary: Dehydrogenase - An enzyme that removes hydrogen ions and high-energy electrons from substrates during cellular respiration.

Definition: NAD+ (Nicotinamide Adenine Dinucleotide) - A coenzyme that acts as a hydrogen acceptor and carrier in cellular respiration.

Highlight: The increased surface area of the inner mitochondrial membrane in cells with high energy demands allows for more frequent and efficient electron transport chain activity.

Definition: Cellular respiration - The metabolic process by which cells break down glucose through a series of enzyme-controlled reactions to release energy in the form of ATP.

Example: ATP is used for various cellular processes, including active transport across cell membranes and the synthesis of new proteins.

Highlight: The presence of oxygen allows for more energy to be released during cellular respiration compared to anaerobic processes.

Vocabulary: ATP synthase - A membrane protein that catalyzes the synthesis of ATP using the energy from the flow of hydrogen ions.

Highlight: The bulk of ATP production occurs due to the action of ATP synthase, which is driven by the return flow of hydrogen ions across the mitochondrial membrane.

Example: The rotation of part of the ATP synthase protein, caused by the flow of hydrogen ions, catalyzes the synthesis of ATP from ADP and inorganic phosphate.