Download Cellular Respiration and Fermentation

Cellular Respiration and
Fermentation
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Learning Outcomes
After reading this chapter and attending lecture,
you should have an understanding of:
•  Aerobic respiration including glycolysis, TCA
cycle, Electron transport chain
•  The difference between substrate and oxidative
phosphorylation
•  Oxidation / Reduction equations
•  The anaerobic cycle includes lactic acid and
alcohol fermentation
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Theme: Life Requires Energy Transfer & Transformation
Figure 1.6b
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Theme: Energy conversions
Bioluminescence: Energy converted to
light energy.
Reactions in our bodies: conversion of
chemical energy or metabolism
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Metabolism
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Catabolism: breakdown complexes (as in cellular
respiration)
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Metabolism – Anabolism biosynthesis
Anabolic and catabolic pathways are linked
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Metabolism – Catabolic and anabolic pathways
Catabolic
Anabolic
•  Metabolic pathways that •  Metabolic pathways that
RELEASE energy by
CONSUME energy to
breaking down complex
build complicated
molecules to simpler
molecules from simpler
compounds
ones
•  Ex. Cellular Respiration •  Ex. Photosynthesis
•  Glucose à H2O + CO2
•  H2O + CO2 à glucose
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What or Who does work?
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Oxidation & reduction
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Oxidation & reduction
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Oxidation of fuel during cellular respiration
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NAD
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Figure 9.5
H2 + 1/2 O2
2H
+
Free energy, G
Free energy, G
spor
tran
tron ain
ch
Explosive
release of
heat and light
energy
Elec
(from food via NADH)
Controlled
release of
+
2H + 2e
energy for
synthesis of
ATP
t
O2
1/
2
O2
ATP
ATP
ATP
2 e2
H+
H 2O
(a) Uncontrolled reaction
1/
2
H 2O
(b) Cellular respiration
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Figure 9.UN05
The Stages of Cellular Respiration
1. Glycolysis (color-coded teal throughout the chapter)
2. Pyruvate oxidation and the citric acid cycle
(color-coded salmon)
3. Oxidative phosphorylation: electron transport and
chemiosmosis (color-coded violet)
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Figure 9.UN05
The Stages of Cellular Respiration
***See video on cellular respiration
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Figure 9.UN05
Substrate level phosphorylation
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Figure 9.UN05
Glycolysis: Investment and payoff
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Figure 9.UN05
Investment Phase-using ATP
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Figure 9.UN05
Payoff Phase – making ATP
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Figure 9.UN05
Where does the pyruvate go?
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Figure 9.UN05
Citric Acid,
Krebs,
TCA cycle
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Figure 9.UN05
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Chemo-osmosis
ATP-synthase
Paul D. Boyer and John E.
Walker -1997 Nobel Prize
http://en.wikipedia.org/wiki/ATP_synthase
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Figure 9.UN05
Fermentation
Fermentation overview animation
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Figure 9.UN05
Anaerobic & aerobic respiration
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Figure 9.UN05
Connecting
Metabolic
Pathways
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Figure 9.UN05
Control of
Cellular
Respiration
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Figure 9.UN05
Review
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Cellular respiration can best be described as
a)  Using energy released from breaking highenergy covalent bonds in organic molecules to
make ATP
b)  Taking electrons from food and giving them to
phosphate to make ATP
c)  Taking electrons from food and giving them to
oxygen to make water, and using the energy
released to make ATP
d)  Converting higher energy organic molecules to
lower-energy organic molecules, and using the
energy released to make ATP
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During glycolysis, for each mole
of glucose oxidized to pyruvate
a)  6 moles of ATP are produced.
b)  4 moles of ATP are used, and 2 moles of ATP
are produced.
c)  2 moles of ATP are used, and 4 moles of ATP
are produced.
d)  2 moles of ATP are used, and 2 moles of ATP
are produced.
e)  net 4 moles of ATP are produced.
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Glycolysis
To sustain high rates of glycolysis under
anaerobic conditions, cells require
a)  functioning mitochondria.
b)  oxygen.
c)  oxidative phosphorylation of ATP.
d)  NAD+.
e)  All of the above are correct.
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What pathways generate
reduced electron carriers?
a) 
b) 
c) 
d) 
e) 
The citric acid cycle
Glycolysis
Pyruvate oxidation
All of the above
Glycolysis and the citric acid cycle only
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Drugs known as uncouplers facilitate diffusion
of protons across the membrane. When such
a drug is added, what will happen to ATP
synthesis and oxygen consumption, if the
rates of glycolysis and the citric acid cycle stay
the same?
a)  Both ATP synthesis and oxygen consumption will decrease.
b)  ATP synthesis will decrease; oxygen consumption will
increase.
c)  ATP synthesis will increase; oxygen consumption will
decrease.
d)  Both ATP synthesis and oxygen consumption will increase.
e)  ATP synthesis will decrease; oxygen consumption will stay
the same.
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ETC-Rotenone inhibits complex I (NADH
dehydrogenase). When complex I is
completely inhibited, cells will
a)  neither consume oxygen nor
make ATP.
b)  not consume oxygen and will
make ATP only through
glycolysis and fermentation.
c)  not consume oxygen and will
make ATP only through
substrate-level
phosphorylation.
d)  consume less oxygen but still
make some ATP through
both glycolysis and
respiration.
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Energy and Respiration
Newborn mammals have a specialized organ
called brown fat, where cells burn fat to CO2
without capturing the energy to reduce electron
carriers or make ATP. This energy may be
used, instead, to
a)  synthesize glucose from CO2.
b)  directly power muscle contraction.
c)  provide energy for endergonic biosynthetic
reactions.
d)  generate heat.
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Evolution of Metabolic Pathways
Glycolysis is found in all domains of life and is
therefore believed to be ancient in origin. What
can be said about the origin of the citric acid
cycle, the electron transport chain, and the F1
ATPase?
a)  They evolved after photosynthesis generated free
oxygen.
b)  They evolved before photosynthesis and used electron
acceptors other than oxygen.
c)  Individual enzymes were present before photosynthesis
but served other functions, such as amino acid
metabolism.
d)  They evolved when the ancestral eukaryotes acquired
mitochondria.
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The purpose of fermentation reactions is
a)  To regenerate NAD+ so glycolysis can continue
b)  To make alcohol or lactic acid that cells can
metabolize for energy under anaerobic conditions
c)  To make additional ATP when respiration can’t
make ATP fast enough
d)  To slow down cellular oxygen consumption when
oxygen is scarce
e)  To make organic molecules that cells can store
until oxygen becomes available
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If your muscle cells used alcohol
fermentation instead of lactic acid fermentation,
which of the following might occur?
a)  Your cells would make more ATP in
anaerobic conditions.
b)  Your cells would not be able to produce ATP in
anaerobic conditions.
c)  You might become drunk when sprinting to
catch a bus.
d)  Your cells would recycle less NADH to NAD+
in
anaerobic conditions.
e)  Your cells would release less CO2 in anaerobic
conditions.
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Catabolism and Anaerobiosis
During intense exercise, as
muscles go into
anaerobiosis, the body will
increase its consumption of
a)  fats.
b)  proteins.
c)  carbohydrates.
d)  all of the above
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Regulation of Metabolism
How will a respiratory
uncoupler affect the rates of
glycolysis and the citric acid
cycle?
a)  Both will increase.
b)  Both will decrease.
c)  Only glycolysis will
increase because of
fermentation.
d)  Only the citric acid cycle
will increase.
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What is the probable effect on ATP production
of a low-calorie diet?
a) ATP production would decrease due to a reduction in
the availability of fuel molecules.
b) ATP production would increase as stored fats are
catabolized.
c) ATP production would increase if most calories were
provided by fats and decrease if most calories were
provided by high-fiber grains.
d) ATP production would remain constant as stored fats or
other body molecules are oxidized.
e) ATP production would remain constant as long as the
exercise level was increased.
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