Download 3.-electron-transport-chain-ATP-synthesis

(7) Cellular Respiration
(A) Role of ATP
&
Phosphorylation
(B)
The metabolic
pathway of
respiration:
Glycolysis and the
citric acid cycle
Cellular
Respiration
(C) The metabolic
pathway of
respiration:
electron
transport chain &
ATP synthesis
(E)
Regulation
of pathways
through
feedback
inhibition
(D)
Substrates for
Respiration
Cellular Respiration (c)
• State what is meant by the
electron transport chain
• Describe the process which
occurs across the transport
electron chain
• Describe the formation of ATP
by ATP synthase
Stage 3
Electron Transport Chain
What is it?
• The electron transport chain is a
collection of proteins attached to a
membrane
Electron Transport Chain
• ETC video
• Education Scotland animation
• HigherEd Video
• ETC song
Electron Transport Chain
3 things to note:
• MOVEMENT OF ELECTRONS
 High energy electrons pass from
one protein molecule in the chain
to another
• MOVEMENT OF HYDROGEN IONS
 The energy received allows the proteins to pump hydrogen across the
membrane, so that they can be pumped back across by ATP synthase.
 This movement of H+ ions drives the enzyme to synthesise ATP from
ADP + Pi
• PRODUCTION OF WATER
 When electrons come to the end of the chain, they combine with
oxygen (the final electron acceptor).
 The oxygen then combines with hydrogen to form water.
ATP Synthase
• The bulk of ATP produced is because of ATP synthase (a
membrane protein).
• ATP synthase is driven by the return flow of H+ ions across the
mitochondrial membrane.
• This return flow of H+ ions rotates part of the membrane
protein ATP synthase, catalysing the synthesis of ATP.
Watch the
lower part of
the protein
as it rotates
round
because H+
ions pass
through it!
• The electron transport chain is a collection of
proteins
attached to a membrane.
1
2
• As a result of dehydrogenase
enzyme action
3
during glycolysis
and the citric acid cycle,
4
hydrogen ions and electrons
are removed and
passed on to the coenzymes NAD or FAD to form
5
6
NADH
or FADH2.
• NADH and FADH2 release the high-energy
7
electrons to the electron transport
chain where
they pass along the chain, releasing energy.
8
• The energy is used to pump
H ions across the inner
9
mitochondrial membrane.
10
11
• The return
flow of H ions drives ATP synthase
and
12
produces the bulk of the ATP generated by
12
cellular respiration.
Checklist
 Name of stage
 Location
 Starting molecule(s)
 Intermediate molecule(s)
 Final molecule(s)
 ATP
 Carbon dioxide
 Hydrogen
 Oxygen
 Any other points?
TASK: True or False
ATP synthesis (in more detail!)
1. Low energy electrons are used to pump oxygen Double false!
ions across a membrane
2. Once pumped across the membrane the hydrogen
False!
ions remain there and do not flow back
3. The enzyme involved in ATP synthesis is ATP
False!
synthesisase
False!
4. ATP synthase is not a protein membrane
False!
5. The final hydrogen acceptor is oxygen
6. Oxygen combines with hydrogen ions and
False!
electrons to form carbon dioxide.
7. The return flow of the hydrogen ions rotates
part of the membrane protein ATP synthase,
TRUE
catalysing the synthesis of ATP.
Cellular Respiration (c)
• State what is meant by the
electron transport chain
• Describe the process which
occurs across the transport
electron chain
• Describe the formation of ATP
by ATP synthase