Chapter 14 Energy generation in Mitochondria and Chloroplasts

1
Chapter 14 Energy generation in Mitochondria and
Chloroplasts
Not responsible for 1) the details of redox
relationships, free-energy changes during
e-transport, and molecular properties of
cytochromes on pp 470-476. 2) Detailed mechanism
of the Ps reaction center 3) photosynthesis in
bacteria (pp 488-491)
Virtual Cell Animation e- Transport
Questions in this chapter you should be able to
answer Chapter 14 1, 2, 3, 4, 7, 8, 10, 11, 13,
15, 16, 17, 19, 20, 22
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Where do reactions of cellular respiration occur
in mitochondria?
3
How is oxidation of NADH coupled to ATP synthesis?
NADH reduction is coupled to ATP synthesis
via electron transport H pumping
Which creates a proton-motive force through a
H electrochemical gradient
4
What are the molecular components of the e-
transport system?
Question 14-3, p 463 What are consequences of DNP
and nigericin on the proton gradient?
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Why do e-transport proteins bind e-
? Iron-sulfur groups heme groups of cytochromes
Why do electrons pass between e- transport
proteins? Iron-sulfur groups (lower redox
potential) heme groups (higher redox potential)
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What is the mechanism the ATP synthase?
ATP synthase is also an ATPase
Jmol Membrane model
14-3 ATP synthase
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• What is the evidence that ATP synthesis is driven
  by Chemiosmosis?
• Effect of decouplers pH 2) Artificial systems
• -- bacteriorhodopsin
• -- ATPase

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Energy capture during photosynthesis What is the
structure of chloroplasts? What are the two
stages of Ps?
True or false The light-independent reactions
only occur in the presence of light. Explain.
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How is energy captured by chlorophyll? Antenna
(light harvesting) complex Reaction Center
Chl
Porphyrin ring
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How is ATP and NADH generated during the light
reactions? Z-scheme P680 and P700 Rx
centers Coupling to chemiosmosis NADP
reduction Membrane architecture
Virtual Cell Animation PS II
Question 14-10 p 486 Chloroplasts do not have an
ATP transporter. How then do plant cells obtain
ATP to carry out other metabolic processes?
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How is CO2 fixed into organic form? --
light-independent Rxs -- Calvin / Bensen
cycle -- RUBP carboxylase oxygenase (Rubisco)
Photorespiration The oxygenase activity of
Rubisco is a competing reaction
12
How do some bacteria carry out photosynthesis
without releasing O2? Anoxygenic
photosynthesis by sulfur bacteria
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If we are measure the rate of photosynthesis in
intact leaves, as we do in the photosynthesis
experiment of Intro biology, we get a curve (the
light saturation curve) similar to that shown
here. A. What limits the rate of
photosynthesis during the linear phase? B. What
limits the rate of photosynthesis when O2
production levels off? C. Which of the following
conditions will increase the value of X? 1.
Increasing the number of reaction centers 2.
Adding an uncoupler 3. Increasing the
concentration of CO2 4. Further increasing the
light intensity