PowerPoint Presentation - Ch. 6 Cellular Respiration

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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
(no ETC).
• 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?
• 2 pyruvic acids, 2ATP
and 2NADH are
made.
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
generating 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
• What happens inside the
mitochondria to pyruvic acid?
• 1) It is oxidized while NAD+ is
reduced to NADH, 2) carbon 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.
Glycolysis- ch.7