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Energy Generation 1
Chapter 14 Energy generation in Mitochondria and Chloroplasts
Not responsible for 1) Detailed mechanism of the Ps reaction center (Figure 14-33)2) Photosynthesis in bacteria (pp 480-483)
Questions in this chapter you should be able to answer:Chapter 14: 1 - 4, 6 – 12, 14 - 23
View The Virtual Cell animations for - e- transport - ATP synthase - photosynthesis
Energy Generation 2
A Quick review…
How is energy transferred to ATP?
Substrate-level phosphorylationPi comes from a substrate molecule
Chemiosmotic phosphorylationATP synthesis is coupled to NADH oxidation
Energy Generation 3
How is oxidation of NADH coupled to ATP synthesis?
E- transport - H+ pumping - ATP synthase
Which creates a ‘proton-motive’ force through a H+ electrochemical gradient
Energy Generation 4
What are the molecular components of the e- transport system?
Question 14-3, p 457What are consequences of DNP and nigericin on the
proton gradient?
(Cyt b-c1)
E- transport
Energy Generation 5
Why do electrons pass between e- transport proteins?
Iron-sulfur groups lower redox potential = lower affinity for e-
heme groups higher redox potential = higher affinity
Why do e-transport proteins bind e- ?Iron-sulfur groups heme groups of cytochromes
Energy Generation 6
What is the mechanism the ATP synthase?
ATP synthase can also function as an ATPase
ATP synthase
Jmol ATP synthase model
Energy Generation 7
What is the evidence that ATP synthesis is driven by Chemiosmosis?
Reconstituted systems
QuestionsA) For system ‘B’ to function, what metabolites and pH conditions must exist outside and inside the vesicles?
B) Suppose that system ‘B’ were constituted “inside out”. Diagram this scenario and explain why ATP synthesis would not occur.
C) How could system ‘B’ be made to function as an ATPase?
Energy Generation 8
Energy capture during photosynthesis
What is the structure of chloroplasts?
What are the two stages of Ps?
Explain why the light-independent reactions only occur
in the presence of light.
Energy Generation 9
How is energy captured by chlorophyll?
Antenna (‘light harvesting’) complex
Reaction Center Chl
Porphyrin ring
Energy Generation 10
What does the Z-scheme show?PSII Reaction center
- donates e- to platoquinone
- replaces with e- from H2O
Energy Generation 11
How is ATP and NADH generated during the light reactions?
Z-scheme
P680 and P700 Rx centers
Coupling to chemiosmosis
NADP reduction
Membrane architecture
Question 14-10 p 477Chloroplasts do not have an ATP transporter. How then do plant
cells obtain ATP to carry out other metabolic processes?
PS e- transport