1. KREBS CYCLE & ELECTRON TRANSPORT Chapter 5.3 Continued

2. REMEMBER: The “fork in the road” happens following glycolysis
REMEMBER: The “fork in the road” happens following glycolysis. The presence or absence of _______________ decides which path it takes next.
OXYGEN

3. Flowchart
Section 9-2
Cellular Respiration
Glucose (C6H1206) +
Oxygen (02)
Glycolysis
Krebs Cycle
We will next focus on the Krebs Cycle. This is the path that is taken when oxygen is present.

4. Image from BIOLOGY Miller and Levine; Prentice Hall Publishing
_______________ follows glycolysis if oxygen is present
KREBS CYCLE

5. REMEMBER:
Glycolysis happens in
the ________________
outside the mitochondria.
Krebs cycle happens in
_____________
inside the mitochondria
CYTOPLASM
MATRIX

6. (also called pyruvate) enters the _________________
PYRUVIC ACID
_______________
(also called pyruvate)
enters the _________________
Pyruvic acid joins
with _______________
to form
________________
MITOCHONDRION
COENZYME A
ACETYL - CoA
Diagram by Riedell

7. Carbon dioxide is released into the ________________
WHERE DO THESE GO?
Carbon dioxide is released into the ________________
High energy electron carriers move into the
____________________
atmosphere
ELECTRON TRANSPORT
CHAIN, ETC
(We will come back to this later)

8. Citric Acid Formation:
Krebs Cycle Animation
2 carbon ACETYL-COA combines with a 4 carbon molecule to form a 6-carbon molecule called _______________ .
citric acid

9. WHERE DO THESE GO?
Coenzyme A goes back to pick up another ________________
Citric acid completes the ____________
Pyruvic acid
KREBS CYCLE

10. KREBS CYCLE KREBS CYCLE PRODUCES ____ ___ 3 1 1 4
Krebs Cycle Animation
KREBS CYCLE PRODUCES
____
___ 3 1 1 4

11. WHERE DOES IT GO? →
6 carbons in original glucose are lost as ________________ to atmosphere
Carbon dioxide

12. WHERE DO THESE GO?
ATP can be used directly to supply __________ for the cell.
High energy electron carriers move into the
____________________
energy
ELECTRON TRANSPORT
CHAIN

13. WHERE DOES IT HAPPEN? Glycolysis Glycolysis ____________ Cytosol
KREBS
Glycolysis ____________
Krebs Cycle ____________
Cytosol
Matrix

14. Electron Transport Chain
Flowchart
Section 9-2
Cellular Respiration
Glucose (C6H1206) +
Oxygen (02)
Glycolysis
Krebs Cycle
Electron Transport Chain
We will next focus on the Electron Transport Chain.

15. WHERE DOES IT HAPPEN? ET Glycolysis
KREBS
Enzymes for ELECTRON TRANSPORT CHAIN
are located in the
___________________________
Inner mitochondrial membrane (cristae)

16. ELECTRON TRANSPORT CHAIN
INTERMEMBRANE
SPACE
CRISTAE
Energy Carrying Protein
MATRIX
Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

17. Electron Transport Chain:
Electron Transport Chain Animation
electrons
High-energy _____________ from __________ and __________ are passed along the electron transport chain.
Energy from passing electrons is used to transport _____________________ across the membrane.
NADH FADH2
Hydrogen ions (H+)

18. Electron Transport Chain:
Electron Transport Chain Animation
The pumping of H+ ions into the _______________________ represents potential energy that is harnessed to make ATP.
As H+ ions escape through ion channels back into the matrix, ________________ spins and adds a phosphate to ADP to
form _______
INTERMEMBRANE SPACE
ATP SYNTHASE
ATP

19. Electron Transport Chain:
________________ serves as the final electron acceptor of the electron transport chain. These electrons are at their lowest energy level.
At the end of the electron transport chain, an enzyme combines the electrons with the hydrogen ions and oxygen to form ______________
For every two high energy electrons one _____ is transported to the intermembrane space of the mitochondria.
OXYGEN
water (H2O) H+

20. NADH FADH2 ATP Synthase _ _ _ _ _
Electron Transport Chain Animation
NADH
High-energy electrons from ________ come in at beginning but electrons from _________ come in farther down the chain.
FADH2
ATP
Synthase
Intermembrane
Space _
Matrix _ _ _ _

21. NADH → _____ FADH2 → _____ 3 ATP’s
SO: Two high energy electrons produce 1 ATP
NADH → _____
FADH2 → _____
3 ATP’s
2 ATP’s

22. SO:

23. Figure 9–2 Cellular Respiration: An Overview
WHATS THE BIG PICTURE?
Electrons carried in NADH
Electrons carried in NADH and FADH2
Pyruvic acid
Electron Transport Chain
Krebs Cycle
Glucose
Glycolysis
Cytoplasm
Mitochondrion
H2O
CO2
Heat

24. CELLULAR RESPIRATION includes:
______________________
_______________________
GLYCOLYSIS
KREBS CYCLE
ELECTRON TRANSPORT CHAIN

25. GLYCOLYSIS Happens in ______________ Breaks down ____________
into ________________
Produces
_______ __________
CYTOPLASM
outside mitochondria
1 glucose
2 pyruvic acid (pyruvate) 2 2

26. KREBS CYCLE happens in ________________ Breaks down _________________
Produces:
____ ____
____ ____
MATRIX
inside mitochondria
2 pyruvic acid 2 6 8 2

27. ELECTRON TRANSPORT Enzymes found in _____________
Uses high energy electrons and H+ ions
donated by _______ and _______
Makes ___________
________ acts a final
electron acceptor to produce ________
cristae
inner membrane of mitochondria
NADH FADH2
32 (net) ATP
OXYGEN
H2O

28. Image from BIOLOGY Miller and Levine; Prentice Hall Publishing

29. CELLULAR RESPIRATION
(aerobic/ with oxygen):
1 glucose → _______________
FERMENTATION (anaerobic/ without oxygen):
1 glucose → ________________
36 ATP
2 ATP

30. CARBOHYDRATES SUPPLY ENERGY
Remember !
CARBOHYDRATES SUPPLY ENERGY
Cells burn GLUCOSE
for their energy needs
Images from:

31. EXERCISE and ENERGY (Short term energy) SMALL GLYCOLYSIS
EXERCISE and ENERGY
(Short term energy)
Cells normally contain _________
amounts of ATP produced by
_______________ &
__________________________ (only enough for a few seconds of activity)
Once this ATP is used up_____________
fermentation can provide enough ATP
to last about ___________________.
SMALL
GLYCOLYSIS
CELLULAR RESPIRATION
LACTIC ACID
90 seconds

32. EXERCISE and ENERGY (Short term energy)
Once race is over, _______________
must be broken down using oxygen.
Well __________ athletes burn lactic acid more efficiently.
Lactic acid
trained
Image from:

33. EXERCISE and ENERGY
(LONGER term energy)
For exercise longer than 90 seconds
_____________________ is the only
way to make enough ATP.
Cellular respiration releases energy
_____________ than fermentation.
Well conditioned athletes must pace themselves during a long race.
Cellular respiration
more slowly

34. GLYCOGEN What happens in a long race when the body’s glucose all
is used up?
Animal cells store
GLUCOSE as
_____________
to use later.
GLYCOGEN
REMEMBER
Image from:

35. MUSCLES glycogen EXERCISE and ENERGY (LONGER term energy)
________________ store glucose as ________________ which can be broken down into glucose to supply energy for_______________
of activity.
MUSCLES
glycogen
15-20 minutes

36. That’s why aerobic exercise must continue for longer than
EXERCISE and ENERGY
(LONGER term energy)
After glycogen stores are used up the body begins to break down ________
That’s why aerobic exercise must continue for longer than
20 minutes if you want to
lose weight!
FAT
Image from:

37. ALL CELLS NEED ENERGY All __________________ (including plant and animal cells) have _______________ for cellular respiration
All __________________ (bacteria)
have their electron transport enzymes
attached to their
_____________________
Remember: No membrane bound organelles!
Eukaryotes
mitochondria
Prokaryotes
Cell membranes