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Chapter 7
Cellular Respiration
Table of Contents
Section 1 Glycolysis and Fermentation
Section 2 Aerobic Respiration
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Chapter 7
Section 1 Glycolysis and Fermentation
Objectives
• Identify the two major steps of cellular respiration.
• Describe the major events in glycolysis.
• Compare lactic acid fermentation with alcoholic
fermentation.
• Calculate the efficiency of glycolysis.
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Chapter 7
Section 1 Glycolysis and Fermentation
Harvesting Chemical Energy
• Cellular respiration is
• Both autotrophs and heterotrophs use cellular
respiration to make
• The products of cellular respiration are the
reactants in photosynthesis; conversely,
• Cellular respiration can be divided into two stages:
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Chapter 7
Section 1 Glycolysis and Fermentation
Harvesting Chemical Energy, continued;
Stage 1
• Stage 1 is
.
• Organic compounds are
• Which produces a small
• Glycolysis is
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Chapter 7
Section 1 Glycolysis and Fermentation
Harvesting Chemical Energy, continued;
Stage 2
• If oxygen is present in the cell’s environment, pyruvic
acid is broken down and
• Pyruvic acid can enter other pathways if
• The combination of glycolysis and these
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Chapter 7
Section 1 Glycolysis and Fermentation
Photosynthesis-Cellular Respiration Cycle
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis
• Cellular respiration begins with glycolysis, which
takes place in
• During glycolysis, one six-carbon glucose molecule
is
• A net yield of
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis, continued; Step 1
• In step 1, 2 phosphate groups
are attached to
• Forms a new
• The phosphate groups are
supplied by
• ATP is then converted into 2
molecules of
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis, continued; Step 2
• In step 2, the 6-carbon
compound formed from step 1
is split
• G3P is also
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis, continued; Step 3
• In step 3, the 2 G3P are
• Each receive a
• Results in 2 molecules of a
• Remember when something
oxidized, something reduced.
– 2 nicotinamide adenine
dinucleotide (NAD+) to
NADH
• NAD+ is organic molecule that
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accepts e- during redox RXNs
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis, continued; Step 4
• In step 4, the phosphate
groups added in steps 1 & 3
are
• This reaction produces 2
molecules of
• Each phosphate is combined
with
• Because a total of 4
phosphate groups were
added in steps 1 & 3,
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Chapter 7
Section 1 Glycolysis and Fermentation
Glycolysis
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation
• If oxygen is not present, some cells can convert
pyruvic acid into other compounds through additional
biochemical pathways that occur in the cytosol.
• Fermentation does not produce ATP, but it does
regenerate ______, which allows for the continued
production of
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Chapter 7
Section 1 Glycolysis and Fermentation
Cellular Respiration Versus Fermentation
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation, continued
• Lactic Acid Fermentation
– In lactic acid fermentation, an enzyme converts
____________ _________ into another threecarbon compound, called ______________
______________.
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation, continued
• Alcoholic Fermentation
– Some plants and unicellular organisms, such as
yeast, use a process called alcoholic
fermentation to convert
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Chapter 7
Section 1 Glycolysis and Fermentation
Two Types of
Fermentation
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation, continued
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation, continued
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Chapter 7
Section 1 Glycolysis and Fermentation
Fermentation, continued
• Through glycolysis, only about _____ percent of the
energy available from the oxidation of glucose is
captured as _________.
• Much of the energy originally contained in glucose is
still held in _____________ ______________.
• Glycolysis alone or as part of fermentation is not very
efficient at
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Chapter 7
Section 2 Aerobic Respiration
Objectives
• Relate aerobic respiration to the structure of a mitochondrion.
• Summarize the events of the Krebs cycle.
• Summarize the events of the electron transport chain and
chemiosmosis.
• Calculate the efficiency of aerobic respiration.
• Contrast the roles of glycolysis and aerobic respiration in
cellular respiration.
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Chapter 7
Section 2 Aerobic Respiration
Overview of Aerobic Respiration
• In eukaryotic cells, the processes of aerobic
respiration occur in the ________________. Aerobic
respiration only occurs if ______________ is present
in the cell.
• The Krebs cycle occurs in the ________________
___________________. The electron transport chain
(which is associated with chemiosmosis) is located in
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Chapter 7
Section 2 Aerobic Respiration
Overview of Aerobic Respiration
Two stages of aerobic respiration:
1.
2.
In prokaryotes aerobic respiration takes place
in the
The mitochondrial matrix contains enzymes
that
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle
• In the mitochondrial matrix, pyruvic acid produced in
glycolysis reacts with ________________ to form
_____________________ Then, ____________________
enters the ________________________.
• One glucose molecule is completely broken down in two
turns of the Krebs cycle. These two turns produce
• The bulk of the energy released by the oxidation of glucose
still has not been
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle, continued; Step 1
• In step 1, a 2-carbon
molecule of
• This reaction
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle, continued; Step 2
• In step 2, citric acid
releases a
• By losing a hydrogen
atom with its e-,
• The e- in the
hydrogen atom is
transferred to
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle, continued; Step 3
• In step 3, the 5carbon compound
formed in step 2
also
• NAD+ is
• A molecule of ATP
is
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle, continued; Step 4
• In step 4, the 4-carbon
compound formed in
step 3 releases a
• The hydrogen is used
to
• FAD similar to
• Like NAD+, FAD
accepts
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Chapter 7
Section 2 Aerobic Respiration
The Krebs Cycle, continued; Step 5
• In step 5, the 4carbon compound
formed in step 4
releases a
• The e- in the
hydrogen reduces
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Chapter 7
Section 2 Aerobic Respiration
Krebs Cycle
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Chapter 7
Section 2 Aerobic Respiration
Electron Transport Chain and Chemiosmosis
• High-energy electrons in hydrogen atoms from _________ and
_________ are passed from molecule to molecule in the
electron transport chain along the inner mitochondrial
membrane.
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Chapter 7
Section 2 Aerobic Respiration
Electron Transport Chain and
Chemiosmosis, continued
• Protons (hydrogen ions, H+) are also given up by _______
and ___________.
• As the electrons move through the electron transport
chain, they lose energy. This energy is used to pump
• The resulting high concentration of protons creates a
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Chapter 7
Section 2 Aerobic Respiration
Electron Transport Chain and
Chemiosmosis, continued
• As protons move through ATP synthase and down their
concentration and electrical gradients, ATP is produced.
Oxygen combines with the electrons and protons to form
water.
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Chapter 7
Section 2 Aerobic Respiration
Electron Transport Chain and
Chemiosmosis, continued
• The Importance of Oxygen
– ATP can be synthesized by chemiosmosis only if
– By accepting electrons from the last molecule in the electron
transport chain, oxygen allows
– As a result, ATP can continue to be made
through __________________.
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Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and
Chemiosmosis, continued; step 1
• In step 1, NADH &
• NADH donates e- at the
• Both molecules also give
up
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Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and
Chemiosmosis, continued; step 2
• In step 2, the e- are
passed
• As they move from
molecule
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Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and
Chemiosmosis, continued; step 3
• In step 3, the energy
lost from the e- is used
to pump protons from
the matrix, building a
• A concentration
gradient of protons is
created across
• An electrical gradient is
also created, as the
protons carry a
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Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and
Chemiosmosis, continued; step 4
• In step 4, the
concentration & electrical
gradients of protons
drive synthesis of
• ATP synthase is
embedded in the
• As protons move through
ATP synthase & down
their concentration &
electrical gradients, ATP
is
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Section 2 Aerobic Respiration
Chapter 7
Electron Transport Chain and
Chemiosmosis, continued; step 5
• In step 5, oxygen is the
final acceptor of
• Oxygen also accepts
protons that were a part
of hydrogen supplied by
• The protons, electrons,
&
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Chapter 7
Section 2 Aerobic Respiration
ETC
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Chapter 7
Section 2 Aerobic Respiration
Chemiosmosis
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Chapter 7
Section 2 Aerobic Respiration
Efficiency of Cellular Respiration
• Cellular respiration can produce up to _____ ATP
molecules from the oxidation of a single molecule of
glucose. Most eukaryotic cells produce about _____
ATP molecules per molecule of glucose.
• Thus, cellular respiration is nearly ______ times more
efficient than glycolysis alone.
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Chapter 7
Section 2 Aerobic Respiration
A Summary of Cellular Respiration
• Another Role of Cellular Respiration
– Providing cells with ATP is not the only important
function of cellular respiration.
– Molecules formed at different steps in glycolysis
and the Krebs cycle are often used by cells to
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Chapter 7
Section 2 Aerobic Respiration
Summary of Cellular Respiration
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Chapter 7
Section 2 Aerobic Respiration
Electron Transport Chain and Chemiosmosis
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