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

Sign up for an account

Already have a Quizlet account? .

Create an account


a partial degradation of sugars that occurs without the use of oxygen; a catabolic process

Anaerobic respiration

a catabolic pathway in which oxygen is not consumed as a reactant along with the organic fuel

Cellular respiration

the catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules for the production of ATP; but it is also a synonym for aerobic respiration

Aerobic Respiration

a catabolic pathway in which oxygen is consumed as a reactant along with the organic fuel; the most efficient catabolic pathway


the loss of electrons from a substance


the addition of electrons to a substance


oxidation-reduction reactions

Oxidizing agent

the electron acceptor


a coenzyme that can accept an electron and acts as an electron carrier in the electron transport chain

Electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP


refers to the process of a molecule being covalently bonded to a phosphate group


occurs in the cytosol, begins the degradation process by breaking glucose into two molecules of a compound called pyruvate

Citric acid cycle

A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing pyruvate to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; the second major stage in cellular respiration

Oxidative phosphorylation

the production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration; electron transport and chemiosmosis; "industrial" way of making ATP

Substrate-level phosphorylation

The formation of ATP by an enzyme directly transferring a phosphate group to ADP from an intermediate substrate in catabolism; occurs during glycolysis and the Krebs cycle

Acetyl CoA

the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme


An organic molecule serving as a cofactor (any nonprotein molecule or ion that is required for the proper functioning of an enzyme)


an electron carrier; a coenzyme derived from riboflavin, a B vitamin

Mitochondrial Matrix

the compartment in mitochondria that is enclosed by the intermembrane space


inner foldings of the inner membrane of mitochondria

Intermembrane space

The narrow region between the inner and outer membranes of mitochondria


an iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membrane of prokaryotic cells

Proton pump

An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient generating a membrane potential in the process

Proton gradient

a gradient formed by the difference in proton concentrations across a membrane


the process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work such as the synthesis of ATP

Electrochemical gradient

the diffusion gradient of an ion, which is affected by both the concentration difference of the ion across a membrane and the ion's tendency to move relative to the membrane potential

Proton-motive force

the potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across a biological membrane during chemiosmosis

ATP synthase

A complex of several membrane proteins that provide a port through which protons diffuse. This complex functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion concentration gradient to make ATP; found in the inner mitochondrial membrane of eukaryotic cells and the plasma membrane of prokaryotic cells

Obligate aerobe

An organism that requires oxygen for cellular respiration and cannot live without it

Obligate anaerobe

An organism that only carries out fermentation or anaerobic respiration; such organisms cannot use oxygen and in fact may be poisoned by it

Facultative anaerobe

an organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present

Alcohol fermentation

a type of fermentation where the pyruvate is converted to ethanol (ethyl alcohol) in two steps

Lactic acid fermentation

a type of fermentation where the pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2

Beta oxidation

a metabolic sequence that breaks the fatty acids down to two-carbon fragments, which enter the citric acid cycle as acetyl CoA


an organelle in eukaryotic cells that serves as the site of cellular respiration

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