Fig. 9-8c, p. 142

1
inner membrane
pyruvate from cytoplasm
electron transport system
H
Coenzymes give up electrons, hydrogen (H) to
transport system
e-
NADH
acetyl-CoA
e-
NADH
H
TCA cycle
H
FADH2
As electrons pass through system, H is pumped
out from matrix
e-
carbon dioxide
Oxygen accepts electrons, joins with 2H, forms
water
ATP synthesized
ATP
2
Pi
ADP
oxygen
H
INTERMEMBRANE space
H
MATRIX
H
H flows in
H
Fig. 9-8c, p. 142
2
Basis of photosynthesis Light energy is used to
transform C-O and H-O bonds into C-C and H-C
bonds
H
Energy


Increased potential energy
O
Basis of respiration Energy is liberated by
transforming C-C and C-H bonds into C-O and H-O
bonds
H
Energy


Decreased potential energy
O
3
Overall Respiration Reaction

• C6H12O6 6O2 ? 6CO2 6H2O energy

7 C-O bonds 5 C-C bonds 7 C-H bonds 5 H-O
bonds 12 O-O bonds 36 covalent bonds
24 C-O bonds 12 H-O bonds 36 covalent bonds
4
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5
Photosynthesis

• Chapter 10

6
Overall Photosynthesis Reaction

• 6CO2 6H2O energy ? C6H12O6 6O2

Oxygen
Glucose
Carbon dioxide
Water
7 C-O bonds 5 C-C bonds 7 C-H bonds 5 H-O
bonds 12 O-O bonds 36 covalent bonds
24 C-O bonds 12 H-O bonds 36 covalent bonds
7

• From seed to tree.
• Where does MOST of the weight gain come from?
• Nutrients from the soil?
• Water?
• Air?
• http//chlorofilms.org/index.php/crpVideo/display/
  videoid/47
• http//www.youtube.com/watch?v5W_aV_w3kko

8

Location of photosynthesis in the plant cell
Photosynthesis
Cell wall
CHLOROPLAST
CHLOROPLAST
MITOCHONDRIUM
NUCLEUS
MITOCHONDRIUM
MITOCHONDRIUM
CYTOSOL
CHLOROPLAST
CHLOROPLAST
MITOCHONDRIUM
Notes 1) cytosol is the same as cytoplasm
2) not all of the plant cell structures and
organelles are shown
9
In photosynthesisChloroplasts
Light microscopic image of chloroplasts in leaf
cells
http//botit.botany.wisc.edu
10
intact chloroplast
stroma
granum
stroma lammellae
Fig. 10-4, p. 152
11
Chloroplasts structure
two outer membranes
thylakoids
stroma
lumen
Fig. 3-12 (a), p. 40
12
stroma
Stroma lammellae
granum
Fig. 10-2a, p. 151
13
Compare to respiration
14
In respiration Mitochondria
inner membrane site of electron transport
chain ATP synthesis
outer membrane
Matrix site of the TCA cycle
cristae
intermembrane space
Fig. 9-8a, p. 142
15
Division of Labor in Chloroplasts

• Green thylakoids
• Capture light
• Liberate O2 from H2O
• Form ATP from ADP and phosphate
• Reduce NADP to NADPH

Light reactions

• Colorless stroma
• Contains water-soluble enzymes
• Captures CO2
• Uses energy from ATP and NADPH for sugar
  synthesis

Dark reactions
16
Light(-dependent) reactions
17
Absorption spectra of Chlorophyll a and b
100
80
chlorophyll b
Percent of light absorbed
60
40
chlorophyll a
20
0
400
500
600
700
Wavelength (nm)
Fig. 10-5, p. 152
18
Two Photosystems involved in trapping light
energy
Pigments (molecules that can receive light energy) Reaction Center Description
Photosystem I Chlorophyll a and b P700 Greater proportion of chlorophyll a than b in light-harvesting complex, sensitive to longer wavelength light
Photosystem II Chlorophyll a and b, carotene P680 Equal amounts of chlorophyll a and b, light-harvesting complex sensitive to shorter wavelength light
light-harvesting complex combination of
pigment molecules that act as light traps
19
An extremely important element
20
Pigment molecules in a light-harvesting complex
(a complex of proteins and pigments) absorb light
energy and transfer it to the reaction center,
where a special chlorophyll a molecule loses an
electron with increased potential energy. This
high energy electron enters an electron transport
chain. Pigments chl chlorophyll car carotene
light
light harvesting complex
Fig. 10-6, p. 153
21
NONCYCLIC ELECTRON TRANSPORT
e-
P700
-0.6
sunlight energy
Electron Transport System
NADPH
e-
P680
e-
potential to transfer electrons (measured in
volts)
0
H NADP
ADP Pi
electron transport system
sunlight energy
e-
e-
P700
0.4
Pigments from the light harvesting complex
photosystem I
released energy used to form ATP from ADP and
phosphate
0.8
photosystem II
e-
H2O
photolysis
P680 reaction center of photosystem II
P700 reaction center of photosystem I