AP Biology Ch. 9 – Cellular Respiration
•Catabolic pathway
•Fermentation
•Aerobic respiration
•Anaerobic respiration
•Cellular respiration
•Redox reaction
•Oxidation/reduction
•Reducing agent
•Oxidizing agent
•NAD+
•Electron transport chain
•Glycolysis
•Citric acid cycle
•Oxidative phosphorylation
•Substrate- level
phosphorylation
•Pyruvate
•Acetyl CoA
•Cytochromes
•ATP synthase
•Chemiosmosis
•Proton-motive force
•Alcohol fermentation
•Lactic acid fermentation
•Obligate anaerobes
•Facultative anaerobes
•Beta oxidation
Catabolic Pathway

A metabolic pathway that releases
stored energy by breaking down
complex molecules
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Fermentation

Catabolic process that makes a limited
amount of ATP from glucose without an
electron transport chain and that
produces a characteristic end product
such as ethyl alcohol or lactic acid
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Aerobic Respiration
Catabolic pathway that consumes
oxygen and organic molecules,
producing ATP.
 This is the most efficient catabolic
pathway and is carried out in most
eukaryotic cells and many prokaryotic
organisms
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Anaerobic Respiration

The use of molecules other than oxygen
to accept electrons at the end of the
electron transport chain
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Cellular Respiration

The catabolic pathways of aerobic and
anaerobic respiration which break down
organic molecules for the production of
ATP
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Redox Reaction
Oxidation-Reduction Reaction
 A chemical reaction involving the
complete or partial transfer of one or
more electrons from one reactant to
another
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Oxidation/Reduction
Oxidation – the loss of electrons from
one substance in a Redox
Reaction
 Reduction – the addition of electrons to
another substance in a
Redox Reaction
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Reducing Agent/Oxidizing Agent
The electron donor in a Redox Reaction
is the reducing agent
 The electron acceptor in a Redox
Reaction is the oxidizing agent
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NAD+

A coenzyme that is the electron carrier
that receives the hydrogen atom (1
proton and 1 electron) before it
continues on to oxygen in energy
releasing steps
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Electron Transport Chain

A sequence of electron carrier
molecules that shuttle electrons during
the redox reactions that release energy
used to make ATP
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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
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Substrate-level Phosphorylation

The formation of ATP by an enzyme
directly transferring a phosphate group
to ADP from an intermediate substrate in
catabolism
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Glycolysis
The splitting of glucose into pyruvate.
 Occurs in almost all living cells
 Serves as the starting point for
fermentation and cellular respiration
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Pyruvate
Ionized form of pyruvic acid
 During glycolysis glucose is split into two
three-carbon sugars and these smaller
sugars are then oxidized and rearranged
to form two molecules of pyruvate
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The Citric Acid Cycle
Also called the Krebs Cycle
 Takes place within the mitochondrial
matrix of eukaryotic cells or the cytosol
of prokaryotes
 Second major phase of cellular
respiration
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Acetyl CoA
Acetyl coenzyme A
 Pyruvate is transformed to Acetyl CoA in
the citric acid cycle
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Cytochromes

Iron-containing protein that is a
component of electron transport chains
in the mitochondria of eukaryotic cells as
well as the plasma membrane of
prokaryotic cells
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ATP Synthase
A complex of several membrane proteins
that provide a port though which proteins
diffuse. This complex functions in
chemiosmosis with adjacent electron
transport chains, using energy of a
hydrogen ion (proton) concentration
gradient to make ATP. Found in
mitochondrial membrane in eukaryotic cells
and the plasma membrane of prokaryotes
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Chemiosmosis

Energy coupling mechanism that uses
energy stored in the form of a hydrogen
ion gradient across a membrane to drive
cellular work such as the synthesis of
ATP. Most ATP synthesis in cells occurs
by chemiosmosis
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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
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Alcohol Fermentation

Glycolysis followed by followed by the
conversion of pyruvate to carbon dioxide
and ethyl alcohol
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Lactic Acid Fermentation

Glycolysis followed by the conversion of
pyruvate to lactate, with no release of
carbon dioxide
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Obligate Anaerobes

An organism that only carries out
fermentation or anaerobic respiration.
Such organisms cannot use oxygen and
in fact may be poisoned by it
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Facultative Anaerobes

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
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Beta Oxidation

A metabolic sequence that breaks fatty
acids down to two-carbon fragments that
enter the citric acid cycle as acetyl CoA
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