Chapter 7 (How Cells Harvest Energy)


Organisms that harvest abiotic energy and store it in organic molecules


Organisms that harvest energy in organic compounds that the autotrophs produce, using them as food. (Depend on autotrophs)

Cellular respiration

All cells harvest energy by breaking bonds and shifting electrons from one molecule to another. (The process by which energy is harvested - the oxidation of organic compounds to extract energy from chemical bonds)


Autotrophs that harvest abiotic chemicals.


Autotrophs that harvest abiotic chemicals.


Electrons lost are accompanied by protons so that what is really lost is a hydrogen atom, not just an electron.

Nicotinamide adenosine dinucleotide (NAD+)

An electron acceptor in redox reactions, accepts electrons and a proton to form NADH.

Aerobic respiration

Cellular respiration in which the final acceptor of electrons is oxygen.

Anaerobic respiration

Cellular respiration in which the final acceptor of electrons is an inorganic molecule other than oxygen.


Cellular respiration in which the final acceptor of electrons is an organic molecule. It is the process that recycles NAD+, the electron acceptor that allows glycolysis to proceed.

Equation of cellular respiration

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy (heat and ATP)

Electron transport chain

Electron carriers located in the mitochondrial inner membrane.

Substrate-level phosphorylation

ATP is formed by transferring a phosphate group directly to ADP from a phosphate-bearing intermediate, or substrate. E.g.: glycolysis

Oxidative phosphorylation

ATP is synthesized by the enzyme ATP synthase, using energy from a proton (H+) gradient. ATP then uses energy from the proton gradient to catalyze the reaction:
ADP+ Pi ---> ATP


First step of aerobic respiration in which glucose (6C) is broken into pyruvate (two 3C molecules) in a ten step process.
1.) The first half of glycolysis consists of five sequential reactions that convert one molecule of glucose into two molecules of the

The Oxidation of Pyruvate to produce Acetyl-CoA

Second step of cellular respiration in which Pyruvate (3C) is oxidized to remove a carbon, producing acetyl-CoA (2C), CO2 and NADH. Acetyl-CoA can be converted to: fat (long term energy storage) or ATP (short term energy storage)

The Krebs Cycle

The third step of cellularA series of nine reactions that occur in the mitochondria.
2 majour steps
A: Priming: Acetyl-CoA (2C) + oxaloacetate (4C) -> citric acid (6C)
B: Energy extraction: Citrate rearrangement and decarboxylation and regeneration of oxa

Electron transport chain

A series of membrane-associated proteins which harvest energy from electron carriers.


The process in which ATP synthase uses the energy of the gradient to catalyze the synthesis of ATP and Pi.


Process in which proteins are broken down in their constituents and the amino groups are removed from the the amino acids to forms molecules that participate in gycolysis and the Krebs cycle.


Series of reactions in which the last 2 carbons in a fatty acid combine with CoA to form acetyl-CoA, which enters the Krebs cycle. It keeps entering until all of its carbons have been burned.