1. How Cells Release Stored Energy
Chapter 7
“Killer” Bees- Aggressive descendents of African honeybees that were imported to Brazil in the 1950s
Africanized bee’s muscle cells have
enlarged __________________
ATP Is ____________ Energy Source
Photosynthesizers get energy from the ___
Animals get energy second- or third-hand from ____ or other ____________
Regardless, the energy is converted to the chemical bond energy of ____

2. Making ATP Two pathways Aerobic Anaerobic O2 required? ___ ___
All organisms- breakdown of carbohydrates, fats, and protein
Plants only - during photosynthesis
Two pathways
Aerobic
Anaerobic
O2 required?
___
___
__________
_________
_________
Process
Location
_________,
__________
____________

3. Aerobic Respiration C6H1206 + 6O2 6CO2 + 6H20 Glucose (C6H12O6)
________ ______ ______ ______
________
Glucose (C6H12O6)
a simple sugar
2 Pyruvate (three carbons)
6CO2

4. Aerobic Respiration 2 ADP 2 ____ 2 ADP 2 _____ 1. ________ 2. _______
3. _______ ________
Glucose
2 Pyruvate
6 CO2
8 NADH
2 NAD+
2 ______
8 NAD+
2 FAD+
2 FADH2
_______
6 ADP
28 ADP
_______
Add up total ATP generated : =____

5. Overview of Aerobic Respiration
_________
CYTOPLASM
glucose
1. ________
(In cytoplasm)
ATP
GLYCOLYSIS
energy input to
start reactions
e- + H+
(2 ATP net)
2 NADH
2 pyruvate
MITOCHONDRION
___________
e- + H+
2 CO2
2 NADH
e- + H+
8 NADH
2. ____________
(in mitochondrial matrix)
4 CO2
KREBS CYCLE
e- + H+ 2
2 FADH2
ATP e-
ELECTRON
TRANSPORT PHOSPHORYLATION
3. ______________
(In inner mitochondrial membrane) 32
ATP H+
water
e- + oxygen
End result: ATP is generated
TYPICAL ENERGY YIELD: 36 ATP

6. 1. Glycolysis
Each of _____ steps in glycolysis is catalyzed by a specific _______.
Divided into two phases:
an _____________ phase
2 ATP used
an _____________ phase.
4 ATP + 2 NADH produced
Net yield in glycolysis
= __ATP + __NADH

7. The Role of Coenzymes ____ and ______ accept electrons and hydrogen
…then deliver them to the ______ _________ system

8. 2. Krebs cycle
2 ADP
2 ATP
2 ADP
2 ATP
________
______
Glucose
2 Pyruvate
6 CO2
8 NADH
2 NAD+
2 NADH
8 NAD+
2 FAD+
2 FADH2
If __________ is present, pyruvate enters the _____________ where enzymes of the Krebs cycle complete the _________ of the organic fuel to carbon dioxide.

9. These are generated by ____________________________
2 ADP
2 ATP
2 ADP
2 ATP
Glucose
2 Pyruvate
6 CO2
What is substrate level phosphorylation?
Enzyme
An ______ transfers a phosphate group from an organic molecule (the substrate) to ____, forming ____-.

10. 2. Krebs cycle The Krebs cycle consists of ____ steps.
Named after Hans Kreb – 1930s
Each cycle produces
one ATP by ________________ ______________
three _________
and one _______
Fig. 9.11

11. The conversion of pyruvate and the Krebs cycle produces large quantities of _____________.
2 carbon atoms enter
2 carbon atoms released as CO2
Note the Krebs cycle is never depleted of ______: 2 in, 2 out
Fig. 9.12

12. 3. Electron transport
Coenzymes deliver electrons to electron transport systems
___________
____________
Electron transport
8 NADH
2 NAD+
___________
8 NAD+
2 FAD+
2 FADH2
__________
6 ADP
28 ADP
__________
Add up total ATP generated : =_____

13. ELECTRON TRANSPORT PHOSPHORYLATION
glucose
GLYCOLYSIS
pyruvate
KREBS CYCLE
ELECTRON TRANSPORT PHOSPHORYLATION
Mitochondria
in-text, p. 116

14. 4 important facts:
Coenzymes deliver _________ to ET chain
H+ ions are delivered to ______ compartment
H+ _________ is created
___ is final _____________

15. Making ATP: __________________ Model
H+ ions going back to _______ compartment generates _______
ATP
INNER
COMPARTMENT
ADP + Pi

16. Overview of respiration
1 Pyruvate from cytoplasm enters inner mitochondrial compartment.
OUTER COMPARTMENT
4 As electrons move through the transport system, H+ is pumped to outer compartment.
NADH
3 NADH and FADH2 give up electrons and H+ to membrane-bound electron transport systems.
acetyl-CoA
NADH
Krebs Cycle
NADH
ATP
ATP
5 Oxygen accepts electrons, joins with H+ to form water.
2 Krebs cycle and preparatory steps: NAD+ and FADH2 accept electrons and hydrogen stripped from the pyruvate. ATP forms. Carbon dioxide forms.
ATP
ATP
free oxygen
ADP + Pi
INNER COMPARTMENT
6 Following its gradients, H+ flows back into inner compartment, through ATP synthases. The flow drives ATP formation.
Fig. 7.5b, p. 114

17. How efficient is respiration in generating ATP?
Complete oxidation of glucose = ____ kcal/mole.
Formation of each ATP requires = _____ kcal/mole.
Efficiency of respiration is
__ kcal/mole x -_ ATP/glucose = __%.
686 kcal/mole glucose
The other approximately 60% is lost as ______.
Cellular respiration is remarkably ________ in energy conversion.

18. ____________ enables some cells to produce ATP without the use of _________
Glycolysis generates ______ whether oxygen is present (aerobic) or not (anaerobic).
Fig. 9.17a
Problem- Fermentation (anaerobic catabolism) still requires NAD+ to accept electrons.
Ethanol
Solution-In __________________, NAD+ comes from the conversion of pyruvate to ______________

19. A second solution to the NAD+ problem:
___________________________
( pyruvate is reduced directly by NADH to form ___________)
Muscle cells switch from ______ respiration to lactic acid f____________ to generate ATP when -____ is scarce.
The waste product, lactate causes muscle fatigue but ultimately it is converted back to pyruvate in the liver.
Lactate

20. A third solution to the NAD+ problem
Certain anaerobic bacteria solve NAD+ problem by using compounds from environment (such as nitrate), NOT oxygen
ATP yield is low

21. Compare respiration and fermentation
Similarities
Both use glycolysis to generate __________
Both use NAD+ as an _________________.
Respiration
Fermentation
Type
Aerobic
Anaerobic
NAD+ regeneration
___
Organic molecules
Energy yield
___ATP
___ ATP

22. At a cellular level, human ______ cells can behave as facultative anaerobes, but __________ cells cannot.
For facultative ________________, pyruvate is a fork in the metabolic road that leads to two alternative routes.
Ethanol or lactate
Fig. 9.18

23. 7. How do other ________________ fit into glycolysis and the Kreb cycle??
Answer- _________,______________________________ can all enter the pathway.
_____ are degraded to amino acids, then deaminated (nitrogen secreted as urea, ammonia)
________ are broken down to glucose.
______ must be digested to glycerol and fatty acids.

24. If glucose is the key to ATP production, then how do we store glucose??
Answer- ___________ (in animals)
_______ and _______ (in plants)
Animals
Glucose absorbed by blood
Pancreas releases insulin
Insulin stimulates glucose uptake by cells
Cells convert glucose to __________________
This traps glucose in cytoplasm where it can be used for glycolysis
If ATP _____, glucose stored as _________ in muscle and liver

25. Using Glycogen When blood glucose low, pancreas releases _____________
Glucagon stimulates liver cells to convert glycogen back to glucose and to release it to the blood
(Muscle cells do not _____________ their stored glycogen)

26. Energy Reserves
Glycogen- ___%
Proteins- ___ %
Fat – ____%

27. Linking photosynthesis and respiration
sunlight energy
PHOTOSYNTHESIS
water +
carbon dioxide
sugar molecules
oxygen
AEROBIC RESPIRATION
in-text, p. 122