Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account


An organism able to build all the complex organic molecules that it requires as its own food source, using only simple inorganic compounds.


An organism that cannot derive energy from photosynthesis or inorganic chemicals, and so must feed on other plants and animals, obtaining chemical energy by degrading their organic molecules.

cellular respiration

The metabolic harvesting of energy by oxidation, ultimately dependent on molecular oxygen; carried out by the Krebs cycle and oxidative phosphorylation.


The breakdown of complex, usually insoluble foods into molecules that can be absorbed into cells, where they are degraded to yield energy and the raw materials for synthetic processes.


Chemical reaction involving the loss of a hydrogen atom. This is an oxidation that combines loss of an electron with loss of a proton.

nicotine adenine dinucleotide (NAD+)

A molecule that becomes reduced (to NADH) as it carries high-energy electrons from oxidized molecules and delivers them to ATP-producing pathways in the cell.

aerobic respiration

The process that results in the complete oxidation of glucose using oxygen as the final electron acceptor. Oxygen acts as the final electron acceptor for and electron transport chain that produces a proton gradient for the chemiosmotic synthesis of ATP.

anaerobic respiration

The use of electron transport to generate a proton gradient for chemiosmotic synthesis of ATP using a final electron acceptor other than oxygen.


The enzyme-catalyzed extraction of energy from organic compounds without the involvement of oxygen.

electron transport chain

The passage of energetic electrons through a series of membrane-associated electron-carrier molecules to proton pumps embedded within mitochondrial or chloroplast membranes.


A three-carbon molecule that is the end product of glycolysis; each glucose molecule yields two pyruvate molecules.


The product of the transition reaction between glycolysis and the Krebs cycle. Pyruvate is oxidized to acetyl-CoA by NAD+, also producing CO2, and NADH.

Krebs cycle

Another name for the citric acid cycle; also called the tricarboxylic acid (TCA) cycle.


The mechanism by which ATP is generated in mitochondria and chloroplasts; energetic electrons excited by light (in chloroplasts) or extracted by oxidation in the Krebs cycle (in mitochondria) are used to drive proton pumps, creating a proton concentration gradient; when protons subsequently flow back across the membrane, they pass through channels that couple their movement to the synthesis of ATP.

glyceraldehyde 3-phosphate (G3P)

The three-carbon molecule that is the product of the reaction that splits a 6-carbon diphosphate during glycolysis. G3P is also an intermediate in the Calvin cycle during photosynthesis.

flavin adenine dinucleotide (FAD)

A cofactor that acts as a soluble (not membrane bound) electron carrier (can be reversibly oxidized and reduced).

NADH dehydrogenase

An enzyme located on the inner mitochondrial membrane that catalyzes the oxidation by NAD+ of pyruvate to Acetyl-CoA. This reaction links glycolysis and the Krebs cycle.


The removal of an amino group; part of the degradation of proteins into compounds that can enter the Krebs cycle.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording