The Stages
of Cellular
Respiration
9.2, 9.3, 9.4
The 3 Stages
Stage 1 –
Glycolysis –
occurs in the
cytosol
Stage 2 – The
Citric Acid
Cycle (aka
Kreb’s Cycle)
– occurs in
t...
Glycolysis
• Glyco = sugar
• Lysis = break
Glycolysis is the first step
This step occurs in the cytosol
In this step, 6-ca...
Glycolysis
Actually a series of 10 reactions that occur
No oxygen is required
No CO2 is released
Glycolysis
• Step 1 - the endergonic, energy investment
phase
– glucose is take in to cytosol
– 2 ATP are used to “kick of...
Go to your diagram
Glycolysis
• Step 2 – the exergonic, energy payoff phase
– The 3 carbon sugar is oxidized and NADH is formed
• 2 Pyruvate ...
Go to
your
diagram
Glycolysis Summary
1 glucose  2 pyruvate + 2 water
2 ATP used + 4 ATP formed  net gain of 2
ATP
2NAD+ + 4 e- + 4 H+ 2 N...
Aerobic Glycolysis
• NAD+ gains a hydrogen and an electron
and becomes NADH
• NADH = an electron‑ carrier
• Energy from 1 ...
Glycolysis Summary
• Glycolysis only released a
small amount of the
energy in glucose
• Lots of energy still in the
pyruva...
Can you explain it?
• Where?
• What goes in?
• What is produced?
Formation of Acetyl CoA, the linking step
between glycolysis and the citric acid cycle
• Pyruvate enters the
mitochondria ...
Go to
your
diagram
Can you explain it?
• Where?
• What goes in?
• What is produced?
The Citric Acid Cycle
• 8 steps
• Overall, from each molecule
of pyruvate:
– 3 CO2 released (1 from
conversion of pyruvate...
The Citric Acid Cycle
For each turn of the cycle, 2 carbons enter
on acetyl CoA, and 2 carbons leave as
CO2
The Citric Acid Cycle
• The acetyl group of
acetyl CoA joins with
oxaloacetate to form
citrate (the ionized
form of citric...
The Citric Acid Cycle Summary
• Each turn of the cycle produces 2 CO 2, 3
NADH, 1 FADH2, 1 ATP
• So for 1 molecule of gluc...
What do we have so far?
For each molecule of glucose take in:
•
•
•
•

2 pyruvate
2 water
glycolysis
2 ATP
2 NADH
conversi...
Oxidative Phosphorylation – the
electron transport chain and
chemiosmosis
• Occurs in the inner
membrane of the
mitochondr...
The Electron Transport Chain
• Made up mostly of
proteins in the
mitochondrial membrane

• Electrons delivered to
the chai...
The Electron
Transport Chain
• Electrons are
shuttled down the
chain from one
electron carrier to
the next
• When the elec...
The Electron Transport Chain
Summary
• No ATP produced directly
from the electron transport
chain
• It functions in contro...
Chemiosmosis
• All throughout the inner membrane of the
mitochondria are proteins called ATP
synthase
Chemiosmosis
• H+ ions accumulate
during the electron
transport chain
• This creates an ion
gradient across the
membrane

...
Chemiosmosis
• So chemiosmosis = the energy from a
hydrogen ion gradient is used to drive
cellular work, such as the forma...
Chemiosmosis
• As hydrogen ions
flow down their
gradient through
the ATP synthase
protein, parts of the
protein spin,
crea...
Chemiosmosis
• The hydrogen ion
gradient is
maintained by the
electron transport
chain
• The electron
transport chain uses...
Very slow animation 

Go to
your
diagram
Cellular Respiration Summary
• 1 glucose molecule 
30 ATP by NADH
4 ATP by FADH2
2 ATP by Citric Acid
Cycle
2 ATP by Glyc...
Cellular Respiration Summary
But…36-38 ATP is the actual total
Slightly less because
1. Ratio of NADH to ATP not a whole n...
Cellular Respiration Summary
• Cellular Respiration is ~ 40% efficient at
storing energy from glucose in ATP
• Best effici...
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
AP Bio Ch. 9 part 2
Upcoming SlideShare
Loading in …5
×

AP Bio Ch. 9 part 2

704 views
518 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
704
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
8
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

AP Bio Ch. 9 part 2

  1. 1. The Stages of Cellular Respiration 9.2, 9.3, 9.4
  2. 2. The 3 Stages Stage 1 – Glycolysis – occurs in the cytosol Stage 2 – The Citric Acid Cycle (aka Kreb’s Cycle) – occurs in the matrix of the mitochondria Stage 3 – Oxidative phosphorylation – the electron transport chain and chemiosmosis – occurs in the cristae of the mitochondria
  3. 3. Glycolysis • Glyco = sugar • Lysis = break Glycolysis is the first step This step occurs in the cytosol In this step, 6-carbon glucose is broken apart into two 3-carbon molecules called pyruvate
  4. 4. Glycolysis Actually a series of 10 reactions that occur No oxygen is required No CO2 is released
  5. 5. Glycolysis • Step 1 - the endergonic, energy investment phase – glucose is take in to cytosol – 2 ATP are used to “kick off” the reaction by phosphorylating the glucose – Once the 2 phosphate groups are attached at either end, the glucose molecule is ready to be split in ½
  6. 6. Go to your diagram
  7. 7. Glycolysis • Step 2 – the exergonic, energy payoff phase – The 3 carbon sugar is oxidized and NADH is formed • 2 Pyruvate molecules are what remains from the original glucose
  8. 8. Go to your diagram
  9. 9. Glycolysis Summary 1 glucose  2 pyruvate + 2 water 2 ATP used + 4 ATP formed  net gain of 2 ATP 2NAD+ + 4 e- + 4 H+ 2 NADH + 2 H+
  10. 10. Aerobic Glycolysis • NAD+ gains a hydrogen and an electron and becomes NADH • NADH = an electron‑ carrier • Energy from 1 NADH is enough to make 3 ATP
  11. 11. Glycolysis Summary • Glycolysis only released a small amount of the energy in glucose • Lots of energy still in the pyruvate molecules • If O2 is available, the pyruvate will enter the mitochondria and aerobic respiration will continue
  12. 12. Can you explain it? • Where? • What goes in? • What is produced?
  13. 13. Formation of Acetyl CoA, the linking step between glycolysis and the citric acid cycle • Pyruvate enters the mitochondria via active transport • One CO2 is broken off of the pyruvate • 2-carbon compound that remains is oxidized to form acetate, and the electron released is used to form NADH • Coenzyme A is attached to the acetate by an unstable bond to form acetyl CoA, which will enter the citric acid cycle
  14. 14. Go to your diagram
  15. 15. Can you explain it? • Where? • What goes in? • What is produced?
  16. 16. The Citric Acid Cycle • 8 steps • Overall, from each molecule of pyruvate: – 3 CO2 released (1 from conversion of pyruvate to acetyl CoA, 2 from the citric acid cycle) – 4 NADH produced (1 from conversion of pyruvate to acetyl CoA, 3 from the citric acid cycle) – 1 FADH2 produced – 1 ATP produced
  17. 17. The Citric Acid Cycle For each turn of the cycle, 2 carbons enter on acetyl CoA, and 2 carbons leave as CO2
  18. 18. The Citric Acid Cycle • The acetyl group of acetyl CoA joins with oxaloacetate to form citrate (the ionized form of citric acid) + • The next steps break down citrate back to oxaloacetate Go to your diagram =
  19. 19. The Citric Acid Cycle Summary • Each turn of the cycle produces 2 CO 2, 3 NADH, 1 FADH2, 1 ATP • So for 1 molecule of glucose, it would be 4 CO2, 6 NADH, 2 FADH2, and 2 ATP
  20. 20. What do we have so far? For each molecule of glucose take in: • • • • 2 pyruvate 2 water glycolysis 2 ATP 2 NADH conversion of • 2 CO2 • 2 NADH • 4 CO2 • 6 NADH • 2 FADH2 • 2 ATP pyruvate to acetyl CoA Citric acid cycle • TOTAL energy yield so far: • 4 ATP • 10 NADH Powerful electron carriers that • 2 FADH2 will shuttle the electrons to the electron transport chain
  21. 21. Oxidative Phosphorylation – the electron transport chain and chemiosmosis • Occurs in the inner membrane of the mitochondria – Inner membrane highly folded into cristae to make lots of surface area for lots of chemical reactions
  22. 22. The Electron Transport Chain • Made up mostly of proteins in the mitochondrial membrane • Electrons delivered to the chain by NADH (delivers electrons to the top of the chain) and FADH2 (delivers electrons to a slightly lower step on the chain)
  23. 23. The Electron Transport Chain • Electrons are shuttled down the chain from one electron carrier to the next • When the electron carrier accepts electrons, it is reduced • It then becomes oxidized when it passes those electrons to its neighbor lower down the chain, which is more electronegative and has a greater affinity for electrons
  24. 24. The Electron Transport Chain Summary • No ATP produced directly from the electron transport chain • It functions in controlling the drop in free energy when electrons “fall” from glucose to oxygen • The released energy is then used to create ATP through chemiosmosis
  25. 25. Chemiosmosis • All throughout the inner membrane of the mitochondria are proteins called ATP synthase
  26. 26. Chemiosmosis • H+ ions accumulate during the electron transport chain • This creates an ion gradient across the membrane • This ion gradient provides the energy to drive the formation of ATP from ADP by the enzyme ATP synthase
  27. 27. Chemiosmosis • So chemiosmosis = the energy from a hydrogen ion gradient is used to drive cellular work, such as the formation of ATP from ADP
  28. 28. Chemiosmosis • As hydrogen ions flow down their gradient through the ATP synthase protein, parts of the protein spin, creating energy that phosphorylates ADP to make ATP
  29. 29. Chemiosmosis • The hydrogen ion gradient is maintained by the electron transport chain • The electron transport chain uses the energy released from moving electrons down the chain to pump H+ across the membrane • This creates a proton-motive force- potential energy stored in the ion gradient • The hydrogen ions then move back down their gradient, through the only door open to them, ATP synthase
  30. 30. Very slow animation  Go to your diagram
  31. 31. Cellular Respiration Summary • 1 glucose molecule  30 ATP by NADH 4 ATP by FADH2 2 ATP by Citric Acid Cycle 2 ATP by Glycolysis Total 38 ATP
  32. 32. Cellular Respiration Summary But…36-38 ATP is the actual total Slightly less because 1. Ratio of NADH to ATP not a whole number 2. ATP yield varies depending on electron carrier (FADH used more in brain, NADH used more in heart & liver) 3. Proton-motive force used to drive other reactions besides formation of ATP (like pulling in pyruvate
  33. 33. Cellular Respiration Summary • Cellular Respiration is ~ 40% efficient at storing energy from glucose in ATP • Best efficiency on cars is 25%

×