CELLULAR RESPIRATION
• CONVERTING FOOD TO ATP
• IN EUKARYOTES OCCURS IN
CYTOPLASM & MITOCHONDRIA
• IN PROKARYOTES OCCURS IN OUTER
MEMBRANES.
• Relate to evolution.
Usain Bolt, Jamaica
• You use energy in the form of ATP to allow
your muscles to move.
• Sprinters have a fast pace & use energy
quickly
Long distance
runners
maintain a
steady pace
and a more
stable supply
of ATP? Why?
SPRINTERS
• Fast pace for a short distance use
anaerobic respiration. Around 400 meters
at this pace, lactic acid starts to build up,
muscles get sore and pace slows.
• Endurance athletes use aerobic respiration.
Muscle fatigue lab
• In your non-writing hand: Squeeze a tennis
ball as many times as you can in 10
seconds.
• A legal squeeze causes a dent from the
heel of your hand in the ball
• Your partner should record the number of
squeezes every ten seconds
• Keep going for 100 seconds
• Average the class data for EACH TRIAL.
Muscle fatigue data table
TRIAL
1
2
3
4
5
6
7
8
9
10
NUMBER OF SQUEEZES IN 10 SECONDS
• What are the independent & dependent
variables in the muscle fatigue experiment?
• Graph class average (bar graph)
• During what time frame(s) does anaerobic
respiration occur?
• During what time frame(s) does aerobic
respiration occur?
Cellular Respiration
• Organic Compounds,
in the presence of
Oxygen, being
converted to Carbon
Dioxide, Water and
ATP.
• Autotrophs –
photosynthesis
• Autotrophs &
heterotrophs –
cellular respiration
Cellular Respiration :
An Overview
• Cells break down glucose to produce ATP.
• Some processes are aerobic (uses oxygen).
• This process yields up to 38 molecules of ATP
from every molecule of glucose.
Cellular Respiration
• Cellular respiration occurs in three
steps:
Glycolysis
The Krebs cycle
Electron transport
•
•
THREE STEPS - OVERVIEW
Cellular Respiration: Glycolysis
• Glycolysis takes place in the cytoplasm of cells.
• The glucose molecule is split into two molecules
of pyruvic acid, releasing two molecules of ATP.
All organisms
do some form
of glycolysis.
Relate to
Glycolysis
anaerobic
6 carbon sugar
yields two
3-carbon pyruvate
molecules
2 NADH
Net gain of 2 ATP
STEPS 1 & 3 endo
or exothermic
reactions?
Spontaneous or
nonspontaneous?
ΔG positive or
negative?
STEPS 5, 6 & 9:
endo or
exothermic
reactions?
Spontaneous or
nonspontaneous?
ΔG positive or
negative?
COUPLED
REACTIONS: One
reaction (break down of
ATP to ADP + Pi) is
necessary for another
reaction
(glucose to glucose 6phosphate)
Relate to entropy.
• The value of ΔG for ATP hydrolysis varies,
primarily depending on Mg2+ concentration,
and under normal physiologic conditions is
about -50 kJ mol−1.
• In humans, approximately 60 percent of the
energy released from the hydrolysis of one
mole of ATP produces metabolic heat rather
than fuel the actual reactions taking place.
What is the ΔG for the synthesis of 1 mole of
glucose 6-phosphate based on the above?
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In the matrix
are
Free ribosomes
Molecules of
ATP Synthase
DNA
And more
Similar in size and function
to bacteria. Reproduce by
binary fission, have DNA,
ribosomes. . . Most likely
existed at one time as a
bacterium.
May be a Symbiotic
relationship.
Between Glycolysis & Krebs
3-carbon pyruvate reacts to form 2-carbon
acetyl CoA and Carbon dioxide (aerobic)
• Where does glycolysis take
place?
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• What is the initial reactant in
glycolysis?
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• Is glycolysis aerobic or
anaerobic? Explain.
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• How many molecules of ATP are
consumed during glycolysis? Is Gibbs free
energy for this reaction negative or
positive? Explain
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• How many molecules of ATP are produced
during glycolysis? What is the net
gain/loss of ATP during glycolysis?
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• If the hydrolysis of ATP has a about -50 kJ
mol−1 value for Gibbs Free Energy and the
synthesis of glucose 6-phosphate
requires 30kJ/mole, explain, in detail, the
most likely differences in Free Energy.
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• Give an example of a coupled reaction in
glycolysis.
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• What other energy-storing molecule is
produced during glycolysis?
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• What is/are the final product(s) of
glycolysis (name and number)
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• Scientists are confident that glycolysis is an
ancient process. Explain how they know
this in evolutionary terms.
30
What evidence (at least 2) is there to support
the theory of symbiosis in regards to the
mitochondria?
31
• How does the cristae affect the surface
area to volume ratio of the mitochondria?
Why is this important?
32
• pyruvate will cross the mitochondrial
membrane via a transport protein down the
concentration gradient. What kind of
transport is this, explain.
33
• The decomposition of pyruvate into carbon
dioxide and acetyl gives off enough energy
to be coupled with what other reaction? In
which of these reactions is Gibbs Free
Energy positive?
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• The carbon dioxide produced by the
decomposition of pyruvate exits the
mitochondria by what process? Explain
how you know.
35
• The decomposition of pyruvate into carbon
dioxide and acetyl is an aerobic process,
meaning what must be present for the
reaction to proceed?
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Cellular Respiration: Krebs Cycle
• The Krebs cycle occurs in the cell’s mitochondria.
• In the Krebs cycle, pyruvic acid is converted to acetic
acid and bound to a molecule of coenzyme A. The
result—acetyl-CoA—and CO2.
• Two molecules of ATP are harvested. Additional
energy is stored in the molecules NADH
and FADH2.
The Kreb’s
Cycle is
sometimes
called the Citric
acid cycle.
Kreb’s
Products:
Cycle 2 Carbon
dioxide from
acetyl
2 ATP
Energy comes
from NADH
and FADH2
which release
high energy
electrons to
the ETC
Cellular Respiration:
Electron Transport
Cellular Respiration: Electron Transport
Electrons carried by NADH and FADH2 are sent
down electron transport chains.
In the process, the electrons lose energy, which is
used to pump hydrogen ions across a membrane
inside the mitochondria.
At the end of the chain, the electrons combine
with O2 to make water.
The concentration gradient generated by pumping
hydrogen ions is used to make ATP.
ENERGY
• STORED IN CARBON-HYDROGEN
BONDS IN GLUCOSE.
• TRANSFERRED TO BOND BETWEEN
2ND & 3RD PHOSPHATE GROUPS IN ATP
THREE STEPS - OVERVIEW
Copy. Convert to cellular
respiration chart.
• Include reactants, products, amount of ATP
consumed, produced, intermediate
reactions.
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Let’s look at the processes
Cellular Respiration
Electron transport chain
ADP becomes ATP at the ATP synthase
protein complex
anaerobic
• Gycolysis still occurs,
• BUT
• Pyruvate will not decompose into acetyl
molecule
• SO
• FERMENTATION
Fermentation
Involves glycolysis but not the other two
stages of aerobic respiration. Many bacteria
and yeasts carry out fermentation. People use
these organisms to make yogurt, bread, wine,
and biofuels. Muscle cells also use
fermentation. when muscle cells cannot get
oxygen fast enough to meet their energy
needs through aerobic respiration. There are
two types of fermentation: lactic acid
fermentation and alcoholic fermentation.
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