Quiz Ch 6

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Quiz Ch 6
1. What molecule does the human body use for
energy for all it’s activities?
Answers for question 2 and 3 include:
carbon dioxide, oxygen, water, glucose, ATP
2. Name one of the molecules (reactants)that the body
uses in respiration to make energy.
3. Name one of the products of respiration.
4. What organelle is important for cellular respiration?
5. T/F Redox reactions involve movement of electrons.
Space Plants
Space Plants
Why are NASA scientists researching plants as a lifesupport system for long-term space flight?
Why are we talking about plants and how they make
oxygen?
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Sunlight energy
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2
Glucose
+
+
H2O
O2
Cellular respiration
in mitochondria
ATP
(for cellular work)
Heat energy
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Together, these two processes
are responsible for most of the
energy needs of life on Earth
Plants give off oxygen and we
take in oxygen. We use this
oxygen along with glucose to
make ATP. ATP is one of the
products of cellular respiration.
• Energy flows into an ecosystem as sunlight
and leaves as heat
• Photosynthesis generates O2 and organic
molecules, which are used in cellular
respiration
• Cells use chemical energy stored in organic
molecules to regenerate ATP, which powers
work
• Main purpose of cellular respiration is to
produce ATP
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Cellular Respiration Reaction
C6H12O6
Glucose
+ 6 O2
Oxygen
6 CO2
Carbon
dioxide
+ 6
H2O
+
Water
ATPs
Energy
 Cellular respiration is a process that releases
energy from the bonds in glucose and captures
the energy as ATP
– Cellular respiration produces 38 ATP molecules from each glucose
molecule
6.5 Cells tap energy from electrons “falling”
from organic fuels to oxygen
 The energy necessary for life is contained in the
arrangement of electrons in chemical bonds in
organic molecules
 An important question is how do cells extract this
energy?
 Gradually
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6.5 Cells tap energy from electrons “falling”
from organic fuels to oxygen
 When the carbon-hydrogen bonds of glucose are
broken, electrons are transferred to oxygen
– Oxygen has a strong tendency to attract electrons
_
+
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Remember water?
+
6.5 Cells tap energy from electrons “falling”
from organic fuels to oxygen
 Energy can be released from glucose by simply
burning it
 The energy is dissipated as heat and light and is
not available to living organisms
Copyright © 2009 Pearson Education, Inc.
6.5 Cells tap energy from electrons “falling”
from organic fuels to oxygen
 On the other hand, cellular respiration is the
controlled breakdown of organic molecules
– Energy is released in small amounts that can be
captured by a biological system and stored in ATP
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6.5 Cells tap energy from electrons “falling”
from organic fuels to oxygen
 A cellular respiration equation is helpful to show the
changes in hydrogen atom distribution
– Glucose loses its hydrogen atoms and is ultimately converted to
CO2
– At the same time, O2 gains hydrogen atoms and is converted to
H2 O
– Loss of electrons is called oxidation
– Gain of electrons is called reduction
Redox
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NADH
NAD+
+
ATP
2e–
Controlled
release of
energy for
synthesis
of ATP
H+
H+
2e–
H 2O
1

2
O2
NADH
Reduced or oxidized?
NAD+
+
ATP
2e–
Controlled
release of
energy for
synthesis
of ATP
H+
H+
Redox reactions involve the
transfer of electrons
2e–
1

2
O2
Reduced or oxidized?
H 2O
The Stages of Cellular Respiration: A Preview
 Cellular respiration has three stages:
 Glycolysis (breaks down glucose into two molecules of
pyruvate)
 The citric acid cycle (completes the breakdown of
glucose)
 Oxidative phosphorylation/chemiosmosis
(accounts for most of the ATP synthesis)
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NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
OXIDATIVE
GLYCOLYSIS
Glucose
and
FADH2
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
animation
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
Inner
mitochondrial
membrane
ATP
Oxidative
phosphorylation
Glycolysis
 What goes in . . .
 What comes out . . .
 Net 2 ATP produced
Glucose
2 Pyruvate + 2 ATP + 2 NADH
Pyruvate and NADH will continue on in
respiration to be the reactants of
subsequent reactions
i.e. - The Citric Acid Cycle
The cell is very efficient and recycles
molecules again and again
Glycolysis
Know this figure
Glucose
2 ADP
2 NAD+
+
2 P
2 NADH
2
ATP
+
2 H+
2 Pyruvate
NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
OXIDATIVE
GLYCOLYSIS
Glucose
and
FADH2
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
animation
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
Inner
mitochondrial
membrane
ATP
Oxidative
phosphorylation
6.8 Pyruvate is chemically groomed for the citric
acid cycle
 The pyruvate formed in glycolysis is transported to
the mitochondria, where it is prepared for entry
into the citric acid cycle
Pyruvate
Acetyl CoA (coenzyme A) + CO2
Acetyl CoA enters the citric acid cycle
CO2 is released by lungs
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NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
OXIDATIVE
GLYCOLYSIS
Glucose
and
FADH2
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
animation
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
Inner
mitochondrial
membrane
ATP
Oxidative
phosphorylation
Acetyl CoA
CoA
CoA
CITRIC ACID CYCLE
2 CO2
3 NAD+
FADH2
3 NADH
FAD
3 H+
ATP
ADP + P
Citric Acid Cycle
 What goes in . . .
 What comes out . . .
 Net 2 ATP produced (1 per each Acetyl CoA molecule)
1Acetyl CoA +
1Oxaloacetate
1Oxaloacetate + 1ATP +
3NADH + 1 FADH + 2CO2
Oxaloacetate is the reactant for the
next cycle of the citric acid cycle
NADH and FADH will continue on in
respiration to be reactants of the next
reaction
i.e. – Oxidative Phosphorylation
NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
OXIDATIVE
GLYCOLYSIS
Glucose
and
FADH2
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
animation
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
Inner
mitochondrial
membrane
ATP
Oxidative
phosphorylation
So far, from 1 molecule of glucose,
We have produced
 10 NADH (2 from glycolysis, 2 from pyruvate processing, 6
from citric acid cycle)
 2 FADH
 4 ATP
 NADH and FADH are our electron carriers that we have been
building up in order to enter oxidative phosphorylation phase
 They will now enter that process and fulfill their purpose:
▫ They have been carrying high energy electrons. They will now
donate these electrons to produce ATP
NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
OXIDATIVE
GLYCOLYSIS
Glucose
and
FADH2
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
animation
animation
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
Inner
mitochondrial
membrane
ATP
Oxidative
phosphorylation
Electrons: Stair Stepping Down in Energy
 As each electron is passed from
protein complex to protein complex it
loses energy
 The energy is used to pump H+ ions
across the membrane to form a gradient
 Each electron steps down an “energy stair” with each
passage
 Until it reaches its final destination and it accepted by
oxygen
 Oxygen will simultaneously accept the electrons and the H+
ions to form water
NADH
NAD+
+
ATP
2e–
Controlled
release of
energy for
synthesis
of ATP
H+
H+
2e–
H 2O
1

2
O2
During oxidative phosphorylation, chemiosmosis
couples electron transport to ATP synthesis
• Following glycolysis and the citric acid cycle,
NADH and FADH2 account for most of the
energy extracted from food
• These two electron carriers donate electrons to
the electron transport chain, which powers ATP
synthesis via oxidative phosphorylation
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Know this figure
NADH
NAD+
+
ATP
2e–
Controlled
release of
energy for
synthesis
of ATP
H+
H+
2e–
H 2O
1

2
O2
The Pathway of Electron Transport
• The electron transport chain is in the cristae of
the mitochondrion
• The carriers accept and donate electrons
• Electrons are finally passed to O2, forming H2O
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Electrons are transferred from NADH or FADH2
to the electron transport chain
• The electron transport chain generates no ATP
• The chain’s function is to break the release of
energy into smaller steps that release energy in
manageable amounts
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Chemiosmosis: The Energy-Coupling Mechanism
• Electron transfer in the electron transport chain
causes proteins to pump H+ from the
mitochondrial matrix to the intermembrane space
• H+ then moves back across the membrane,
passing through channels in ATP synthase
• ATP synthase uses the exergonic flow of H+ to
drive phosphorylation of ATP
• This is an example of chemiosmosis, the use of
energy in a H+ gradient to drive cellular work
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Fig. 9-14
INTERMEMBRANE SPACE
H+
Stator
Rotor
Internal
rod
Catalytic
knob
ADP
+
P
i
ATP
MITOCHONDRIAL MATRIX
Potential energy from electrons is used to synthesize ATP
• Electrons in NADH and FADH contain potential energy.
▫ This energy is used to pump H+ ions across the membrane.
• The H+ gradient contains potential energy.
▫ This energy is used to activate ATP synthase.
• ATP synthase converts this energy and stores it in the form of ATP.
Intermembrane
space
Protein
complex
of electron
carriers
H+
H+
H+
H+
H+
H+
H+
Electron
carrier
H+
H+
ATP
synthase
Inner
mitochondrial
membrane
FADH2
Electron
flow
NADH
Mitochondrial
matrix
FAD
NAD+
1

2
H+
O2 + 2 H+
H+
H+
H2O
Electron Transport Chain
OXIDATIVE PHOSPHORYLATION
ADP + P
H+
Chemiosmosis
ATP
Potential energy from electrons is used to synthesize ATP
• Electrons in NADH and FADH contain potential energy.
▫ This energy is used to pump H+ ions across the membrane.
• The H+ gradient contains potential energy.
▫ This energy is used to activate ATP synthase.
• ATP synthase converts this energy and stores it in the form of ATP.
Intermembrane
space
Protein
complex
of electron
carriers
H+
H+
H+
H+
H+
H+
H+
Electron
carrier
H+
H+
ATP
synthase
Inner
mitochondrial
membrane
FADH2
Electron
flow
NADH
Mitochondrial
matrix
FAD
NAD+
1

2
H+
O2 + 2 H+
H+
H+
H2O
Electron Transport Chain
OXIDATIVE PHOSPHORYLATION
ADP + P
H+
Chemiosmosis
ATP
Many poisons and antibiotics affect the electron
transport chain.
What would happen to a human
or a bacteria if you stopped ATP
synthase? One of the electron
transporters?
Reviewing the big picture
C6H12O6
Glucose
+ 6 O2
Oxygen
6 CO2
Carbon
dioxide
+ 6
H2O
Water
+
ATPs
Energy
 Know the overall equation for cellular respiration
 Where do each of these reactants get consumed?
 Where are the products produced?
 38 ATP from each glucose molecule in aerobic respiration
How many calories are released when 1 gram of
glucose is completely broken down in the presence
of oxygen?
• Each gram of sugar can provide 1.2 X 1023 ATP
or 4 calories
• Each gram of fat can provide 2.7 X 1023 ATP
or 9 calories
• So. . . it is much harder to burn off a pound of fat
because it can contain so many calories. It produces
more than two times the amount of ATP.
How many calories do you have to burn to lose a
pound?
 It is commonly said that a gram of fat contains 9
calories. But there are 454 grams in a pound, and 9
x 454 = 4086 calories, not 3500.
 The reason for the discrepancy is that body fat, or
adipose tissue, contains not only fat, but also other
substances including protein, connective tissue, and
water. The dietary fat referred to in the nutritional
analysis of food is pure.
Counting Calories
Low carb diets
 Low carb diets are based on the theory that restricting the
amount of carbohydrates you eat will cause your body to
burn fat to obtain the energy it needs.
 When we eat, our bodies convert digestible carbohydrates
into blood sugar (glucose), our main source of energy, which
is stored in our liver as glycogen. When we greatly restrict
our intake of carbohydrates, to the point where our liver's
store of glycogen is depleted and our bodies do not find the
usual source of energy readily available, they turn to our fat
stores.
www.atkins.com
Low carb diets
 Through a process called ketosis, our body fat is "burned" or
turned into fuel to provide the energy we need. Our bodies
run on ketones instead of blood sugar.
 Ketosis is related to halitosis (acetone)
 Do low carb diets work in the long run?
 Huge amounts of fat and protein
 Increased cholesterol, kidney stones, decreased bone density
 In the first week or two of a low-carbohydrate diet a great deal of
the weight loss comes from eliminating water
 Body can still use proteins and fats that you are eating for energy
At Atkins, we believe in science - the science it
took to develop our program, the science that
backs it up and the scientific approach we use
to continually improve everything we do.

Our NEW and evolved diet is not the often perceived "all you can eat -bacon, egg, and cheese diet” or the "NO CARBS DIET" as some would
have you believe; but instead; Atkins is a diet rooted in the science of
eating fewer refined carbohydrates and refined sugars – what we refer
to as “bad carbs.”

As you will discover, the new Atkins Diet is an optimally balanced lifetime
eating plan with the flexibility to meet each individual’s unique physical
condition addressing factors such as age, gender, level of physical
activity, and metabolic rate. The lifetime eating plan incorporates "ALL"
food groups while focusing on eating some of the best foods on earth.
Dr Atkins dies in 2003
He is credited with revolutionizing the diet world with his theory that you can lose
weight by eating fat, and his followers hailed him as a pioneer. His critics
accused him of selling a dangerous idea, but Atkins dismissed their claims.
Atkins' diet books were some of the best-selling books of all time.
"See, that's a big mistake ... to tell people to restrict calories," Atkins told CNN in
January. "They lose the weight, they feel fine, then they get to their goal weight
and they still have 60 more years to live, and are they going to go hungry for all
60 years?"
Atkins was a cardiologist and businessman, selling supplements and food on his Web
site and at the Atkins Center for Complementary Medicine.
All of his best-selling diet books promoted the same philosophy: a diet high in fat
and protein and low in carbohydrates is a sure way to lose weight.
"It's not that it needs to be low-calorie. As long as you cut out the carbohydrate the
weight loss is automatic," Atkins said.
Food, such as
peanuts
Carbohydrates
Fats
Glycerol
Sugars
Proteins
Fatty acids
Amino acids
Amino
groups
Glucose
G3P
GLYCOLYSIS
Pyruvate
Acetyl
CoA
ATP
CITRIC
ACID
CYCLE
OXIDATIVE
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
Is fermentation your friend?
6.13 Fermentation enables cells to produce ATP
without oxygen
 Fermentation occurs if there is not enough oxygen
to undergo cellular respiration
 It is Plan B for our cells and used as a last
resort because it is less efficient at
producing ATP
 Fermentation is an anaerobic (without oxygen)
energy-generating process
– It takes advantage of glycolysis, producing two ATP molecules and
reducing NAD+ to NADH
– The trick is to oxidize the NADH without passing its electrons
through the electron transport chain to oxygen
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6.13 Fermentation enables cells to produce ATP
without oxygen
 Your muscle cells and certain bacteria can oxidize
NADH through lactic acid fermentation
– NADH is oxidized to NAD+ when pyruvate is reduced to
lactate
– In a sense, pyruvate is serving as an “electron sink,” a
place to dispose of the electrons generated by oxidation
reactions in glycolysis
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2 ADP
+2 P
2 ATP
GLYCOLYSIS
Glucose
2 NAD+
2 NADH
2 Pyruvate
2 NADH
2 NAD+
2 Lactate
Lactic acid fermentation
During intense exercise, this lactic is
produced faster than is can be removed
from the muscles, used to be thought this
is what made you sore the next day
Lactic Acid Fermentation
 What goes in . . .
 What comes out . . .
 Net 2 ATP produced
 How many ATP are produced with respiration?
1 glucose+
2 NAD+
2 Lactate + 2ATP + 2NADH
Compare this to respiration in which
38 ATP are produced for each
molecule of glucose
Are you a better sprinter or distance runner?
 It is generally accepted that muscle fiber types
can be broken down into two main types: slow
twitch muscle fibers and fast twitch muscle
fibers
 Human muscles contain a genetically determined
mixture of both slow and fast fiber types, usually
about 50/50 but the percentage of muscle fiber
type varies from person to person
Distance runners

The slow twitch muscles are more
efficient at using oxygen to
generate more ATP

This allows continuous, extended
muscle contractions over a long
time

They fire more slowly than fast
twitch fibers and can go for a
long time before they fatigue

Therefore, slow twitch fibers are
great at helping athletes run
marathons and bicycle for hours
Nick Harrison wins the Melbourne Marathon
theage.com
What type of energy making process
are slow twitch muscles using?
Sprinters/body builders

Fast twitch fibers use anaerobic
metabolism to create fuel

Much better at generating short
bursts of strength or speed than slow
muscles.

They fatigue more quickly. Fast twitch
fibers generally produce the same
amount of force per contraction as
slow muscles, but they get their
name because they are able to fire
more rapidly.

They are not effective in longer-term
training, but are very useful in brief,
high-intensity training like we see in
sprinting, bodybuilding, or
powerlifting
What type of energy making process
are slow twitch muscles using?
Fermentation or respiration?
Are Athletes Born or Built?
Can Training Change Fiber Type?
Do you like the white or the dark meat?

Chickens have fast and slow
twitch muscle, too

Dark meat, like in the
drumstick, is mostly made up
of slow twitch fibers


White meat, like in chicken wings
and breasts, is mostly made up of
fast twitch muscle

They use their wings for quick
bursts of flight
Chickens use their legs for
walking and standing, which
they do for extended periods
6.13 Fermentation enables cells to produce ATP
without oxygen
 The baking and winemaking industry have used
alcohol fermentation for thousands of years
– Yeasts are single-celled fungi that not only can use
respiration for energy but can ferment under anaerobic
conditions
– They convert pyruvate to CO2 and ethanol while
oxidizing NADH back to NAD+
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Alcoholic Fermentation
 What goes in . . .
 What comes out . . .
 Net 2 ATP produced
 How many are produced with respiration?
1 glucose+
2 NAD+
2 Ethanol + 2 CO2+ 2ATP + 2NADH
Compare this to respiration in which
38 ATP are produced for each
molecule of glucose
2 ADP
+2 P
2 ATP
GLYCOLYSIS
Glucose
2 NAD+
2 NADH
2 Pyruvate
2 NADH
2 CO2
released
2 NAD+
2 Ethanol
Alcohol fermentation
Alcoholic Beverages
• Made by fermentation
– Beer, wine
– The chemical reaction of yeast on
sugars
Harvesting hops
•
Beers
– Most beers are made from barley malt
– Ground up malt is added to barley to make mash
– Mash is combined with the flavoring, hops, and
fermentation begins
– The fermentation can last for several weeks
–
–
Can use open fermentation and rely on vigorous yeast
action to produce a protective CO2 blanket
The average beer is somewhere between 2-6%
alcohol
Wine
• Made from grapes
– Crush grapes
– Ferment the juices
– Most wines are ferment for 4 years or
more
– Contain 7-24% alcohol
• Why do beer/wine fermentation
reactions have to take place in areas
without oxygen?
• Why does wine have a higher alcohol
percentage than beer?
Wine
• Made from grapes
– Crush grapes
– Ferment the juices
– Most wines are ferment for 4 years or
more
– Contain 7-24% alcohol
• If oxygen were present than yeast
would use the far more efficient
mechanism of respiration
•
The yeasts differ. Most beer yeasts cannot tolerate
high concentrations of alcohol. When a brewer
wants to ferment a high-alcohol beer, he uses a
champagne yeast or specially-bred yeast to finish
the fermentation.
There will be a quiz next class.
It will cover chapters 5 and 6.

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