Transcript PowerPoint Presentation - Ch. 6 Cellular Respiration

Ch. 6 Cellular Respiration
6.6 – 6.10
Redox reactions release energy when electrons fall from a hydrogen
carrier to oxygen
• Where do all the
electrons come from for
the redox reactions in the
cells?
• It comes from NADH
made during the oxidation
of glucose.
• How do electrons make it
to the electron carriers?
• When NADH gives up
electrons to electron
carriers.
• What keeps the electrons
coming down the Electron
transport chain?
• O2 at the bottom pulls
electrons down the
energy hill.
• What happens to the
energy of the electrons as
it falls down the electron
transport chain?
• The energy is used to
pump H+ against their
gradient which then come
back through ATP
synthase to generate ATP
Two ways to make ATP. Chemiosmosis and …
• Do you remember what
chemiosmosis is?
• When ATP is made by
movement of Hydrogen
ions from high to low
concentration via the
protein ATP synthase.
• How does a high
concentration of
hydrogen ions form in the
first place?
• H+ ions are actively
transported using
electron energy
… Substrate-level phosphorylation.
• How does substrate-level
phosphorylation differ
from chemiosmosis?
• No membrane is
involved.
• So what does happen?
• An enzyme helps transfer
a phosphate from a
substrate (an organic
molecule) to an ADP
making an ATP and a
new organic molecule.
• In which process will cells
make more ATP,
chemiosmosis or
substrate-level
phosphorylation.
• More ATP is made in
chemiosmosis.
Respiration occurs in 3 stages:
• What are the first two
stages of cellular
respiration?
• Glycolysis and Krebs
cycle.
• Where does
glycolysis take place?
• In the cytoplasm.
• What happens in
glycolysis?
• Output of 2 pyruvic
acids, ATP and NADH
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Overview of Krebs cycle
Where does the
Krebs cycle occur?
In the mitochondria.
What happens in the
Krebs cycle?
Breaking down
pyruvic acid to acetyl
CoA then oxidizing it
to CO2 and generate
ATP, NADH & FADH2
What way does
glycolysis and Krebs
cycle make ATP?
Substrate-level
phosphorylation.
• Where does glycolysis and
Krebs cycle take energy from?
• Food oxidized to CO2.
• How are electrons carried to
the top of the electron
transport chain?
• NAD+ and FAD (temporarily
becoming NADH & FADH2)
• How does the Electron
transport chain, the third stage
of respiration, make ATP?
• By chemiosmosis, the
movement of Hydrogen ions
from high to low concentration
via the protein ATP synthase
Glycolysis harvest chemical energy by oxidizing glucose to
make pyruvic acid.
• What are all the
compounds called that
form between input of
glucose to output of
Pyruvic acid?
• Intermediates. Even
though there are 9
reactions in glycolysis, we
are only concerned with
the net gain.
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Glycolysis means: Splitting of Sugar
What starts glycolysis?
An investment of energy
in the forms of glucose
and 2 ATP.
What happens to that
investment of energy?
Becomes a payoff of
energy resulting in 4 ATP
and 2 NADH and 2
Pyruvate.
What is produced during
Glycolysis?
2 Pyruvate, 2 ATP, 2
NADH, and 2 H+ and 2
H2O
How is this like selling a
house?
Fix it up, invest to make
it nice to get your payoff
from selling it.
Pyruvic acid is chemically groomed for the Krebs cycle
• After pyruvic acid forms at the
end of glycolysis where does it
go?
• It diffuses from cytoplasm into
the mitochondria, the site of
the Krebs cycle.
• What happens inside the
mitochondria to pyruvic acid?
• 1) Simultaneously it is oxidized
while NAD+ is reduced to
NADH, 2) carbon atom is
released in CO2, 3) coenzyme
A joins remaining 2 carbon
fragment to form Acetyl CoA
• What is the Acetyl CoA used
for?
• It is used as fuel for the Krebs
cycle, the next step.
• For each molecule of glucose
to enter glycolysis how many
molecules of Acetyl CoA enter
the Krebs cycle?
• Two.