Transcript Biology: Life on Earth

Teresa Audesirk • Gerald Audesirk • Bruce E. Byers
Biology: Life on Earth
Eighth Edition
Chapter 7
Capturing Solar Energy:
Photosynthesis
Copyright © 2008 Pearson Prentice Hall, Inc.
Chapter 7 Opener Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
(chloroplast)
FOTOSINTESIS
H2O CO2
ATP
RESPIRACION
CELULAR
(mitochondrion)
Figure 7-1 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
GLUCOSA
O2
(a) Leaves
(b) Internal leaf structure
cuticle
upper
epidermis
mesophyll
cells
(d) Chloroplast
lower
epidermis
chloroplasts
stoma
outer membrane
inner membrane
thylakoid
vascular bundle
(vein)
stoma
bundle sheath
stroma
channel
interconnecting
thylakoids
Figure 7-2 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
(c) Mesophyll cell
containing
chloroplasts
Leaves
Figure 7-2a Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Internal leaf structure
cuticle
upper
epidermis
mesophyll
cells
lower
epidermis
stoma
stoma
vascular bundle bundle
sheath
(vein)
Figure 7-2b Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
chloroplasts
Mesophyll cell containing chloroplasts
Figure 7-2c Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Chloroplast
outer membrane
inner membrane
thylakoid
stroma
channel
interconnecting
thylakoids
Figure 7-2d Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Figure 7-3 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
H 2O
LIGHT-DEPENDENT
REACTIONS
(in thylakoids)
DEPLETED
CARRIERS
(ADP, NADP+)
CO2
ENERGIZED
CARRIERS
(ATP, NADPH)
LIGHT-INDEPENDENT
REACTIONS
(in stroma)
Figure 7-4 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
O2
glucose
Absorbance of photosynthetic pigments
light absorption (percent)
chlorophyll b
carotenoids
chlorophyll a
Wavelength (nanometers)
Visible light
Gamma rays
X-rays UV
higher energy
(too much)
Infrared
Microwaves
Radio
waves
lower energy
(not enough)
Figure 7-5 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Figure 7-6 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
energy level of electrons
sunlight
7
6
3
8
2e–
5
2e–
2
2e–
4 energy to drive
ATP synthesis
reaction
center
1
HO9
2e– 2
2H+
photosystem II
1/2 O2
Figure 7-7 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
photosystem I
2e–
NADPH
NADP+
H+
thylakoid
chloroplast
Figure 7-8 (part 1) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Energy from energized
electrons powers active
transport of H+ by ETC.
PSII
ETC
PSI
Energy-carrier
molecules power
the C3 cycle.
stroma
ETC
C3
cycle
Energy from
energized
electrons powers
NADPH synthesis.
thylakoid space
High H+ concentration
generated by active
transport.
H+ channel coupled
to ATP-synthesizing
enzyme.
Figure 7-8 (part 2) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Flow of H+ down
concentration gradient
powers ATP synthesis.
1 Energy is released as
water flows downhill.
2 Energy is
harnessed to
rotate turbine.
3 Energy of rotating
turbine is used to
generate electricity.
Figure E7-1 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
thylakoid
chloroplast
Figure E7-2 (part 1) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
photosystem II
Active transport
of hydrogen ions.
thylakoid
membrane
2e–
stroma
High H+ concentration
in thylakoid space.
H+ ion channel coupled
to ATP synthesizing
enzyme.
Flow of H+ powers
ATP synthesis.
ADP
P
ATP
Figure E7-2 (part 2) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Figure 7-9 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
1 Carbon
fixation
combines
CO2 with
RuBP.
6 CO2
2 G3P
synthesis
uses energy.
6
12
6 RuBP
3 RuBP
synthesis
uses energy
and 10 G3P.
PGA
C3 cycle
(Calvin-Benson cycle)
12 ATP
12 ADP
6
ADP
6
ATP
4 G3P available
for synthesis
of glucose.
12 NADPH
12
G3P
glucose
(or other molecules)
Figure 7-10 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
12 NADP+
energy from
sunlight
O2
CO2
ATP
NADPH
Light-dependent
reactions are
associated with
thylakoids.
ADP
Lightindependent
reactions
(C3 cycle) occur
in stroma.
NADP+
H2O
chloroplast
sugar
Figure 7-11 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
C3 plants use the C3 pathway
Much photorespiration
occurs under hot, dry
conditions.
CO2
O2
PGA
C3
Cycle
rubisco
CO2
RuBP
G3P
glucose
stoma
within mesophyll chloropast
bundlesheath
Little glucose
cells
is synthesized.
In a C3 plant, mesophyll cells
contain chloroplasts; bundlesheath cells do not.
Figure 7-12a Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
C4 plants use the C4 pathway
CO2 is captured with
a highly specific enzyme.
CO2
PEP
AMP
C4
Pathway
4-carbon
molecule
ATP
pyruvate
PGA
stoma
bundlesheath
cells
within mesophyll
chloropast
CO2 O2
rubisco
C3
Cycle
G3P
glucose
In a C4 plant, both mesophyll
and bundle-sheath cells contain
chloroplasts.
CO2
RuBP
Almost no
photorespiration
occurs in hot, dry
conditions.
within bundle-sheath
chloropast
Lots of glucose is synthesized.
Figure 7-12b Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.