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35 terms

AP Biology- Chapter 9 (Cellular Respiration)

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Fermentation
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
Oxidation
the loss of electrons from a substance
Reduction
the addition of electrons to a substance
Redox
oxidation-reduction reactions
Oxidizing agent
the electron acceptor
NAD+
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
Phosphorylation
refers to the process of a molecule being covalently bonded to a phosphate group
Glycolysis
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
Coenzyme
An organic molecule serving as a cofactor (any nonprotein molecule or ion that is required for the proper functioning of an enzyme)
FAD
an electron carrier; a coenzyme derived from riboflavin, a B vitamin
Mitochondrial Matrix
the compartment in mitochondria that is enclosed by the intermembrane space
Cristae
inner foldings of the inner membrane of mitochondria
Intermembrane space
The narrow region between the inner and outer membranes of mitochondria
Cytochrome
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
Chemiosmosis
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
Mitochondrion
an organelle in eukaryotic cells that serves as the site of cellular respiration