.

1. Bio 111
2009

2. • Luz se transforma en energía química
(compuesto orgánico)
• Ocurre en el cloroplasto
• Requiere pigmentos fotosintéticos
• Plantas, algas, bacterias fotosintéticas
• CO2 se convierte en carbohidrato

3. luz
6 CO2 + 12H2O ---> C6H12O6 +6O2 +6H2O
clorofila

4. (chloroplast)
photosynthesis
CO ATP sugar O2 2 H2O
cellular
respiration
(mitochondrion)
Figure 7-1 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

5. Luz
◦ Compuesta de fotones
 Luz visible es una porción
pequeña del espectro
electromagnético
◦ La energía viaja en ondas
◦ Onda corta más energía que onda
larga

6.  Fotosíntesis es un proceso
redox
◦ Se captura la energía solar y se
transforma en carbohidrato
◦ Hidrógenos del agua reducen el
carbono
◦ Oxígeno del agua se oxida

7. TV and
radio
waves
Micro-waves
Infrared
Visible
UV
X-rays
Gamma
rays
Color
spectrum
of visible
light
One wavelength
Longer wavelength
Red
Orange
Yellow
Green
Blue
Violet
760 nm
700 nm
600 nm
500 nm
400 nm
380 nm
Electromagnetic
spectrum Shorter wavelength

8. 100μm
(a)
Wavelength of light (nm)
(b)

9.  Cloroplastos
◦ Organelos rodeados de doble
membrana
◦ Lugar de fotosíntesis
◦ Localizados principalmente en el
mesófilo de la hoja

10. Palisade
mesophyll
Vein
Spongy mesophyll
(a) Stoma

11. Chloroplast
outer membrane
inner membrane
thylakoid
stroma
channel
interconnecting
thylakoids
Figure 7-2d Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

12. (b) 10μm
Thylakoids Outer membrane
Inner
membrane
Intermembrane
space
Thylakoid
membrane
Stroma Granum
(stack of
thylakoids)
Thylakoid
(c) lumen

13.  Clorofila
◦ Pigmento fotosintético -principal
◦ Clorofila a, clorofila b, carotenoides,
se encuentran en las membranas
tilacoides de los cloroplastos

14.  Fotosistemas I y II
◦ Dos tipos de unidades fotosintéticas
◦ Cada fotosistema incluye
 Moléculas de clorofila
 Complejos de antenas
◦ Centro de reacción del Fotosistema I
 P700 pico de absorción en 700 nm
◦ Centro de reacción Fotosistema II
 P680 pico de reabsorción en 680 nm

15. Primary
electron
acceptor
Photon
Thylakoid
Chloroplast
Photosystem
Antenna
complexes
Reaction
center
e–

16. Estimated absorption (%)
Chlorophyll b
Chlorophyll a
Wavelength (nm)
(a)
Relative rate of photosynthesis
Wavelength (nm)
(b)

17. chlorophyll b
carotenoids
Wavelength (nanometers)
Micro-waves
Gamma rays X-rays UV Infrared
Figure 7-5 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
Radio
waves
Visible light
higher energy
(too much)
lower energy
(not enough)
light absorption (percent)
Absorbance of photosynthetic pigments
chlorophyll a

18.  Fases de fotosíntesis
◦ Dependiente de luz
 tilacoides
 Los electrones energizados por la luz se
convierten en ATP
◦ Fijación de carbono
 estroma
 Compuestos productos de la fase
dependiente se requieren para la
formación de carbohidrato

19. H2O
DEPLETED
CARRIERS
(ADP, NADP+)
CO2
LIGHT-DEPENDENT
REACTIONS
(in thylakoids)
O2
ENERGIZED
CARRIERS
(ATP, NADPH)
LIGHT-INDEPENDENT
REACTIONS
(in stroma)
Figure 7-4 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
glucose

20. O2
energy from
sunlight
ATP
NADPH
Light-dependent
reactions are
associated with
thylakoids.
chloroplast
CO2
Light-independent
reactions
(C3 cycle) occur
in stroma.
ADP
NADP+
sugar
H2O
Figure 7-11 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

21.  La luz es absorbida por la clorofila
 Clorofila excitada-nivel energético alto
 Libera electrones altos en energía, se ioniza,
queda con carga positiva-Fotoionización
 Electrones pasan cadena transporte
 Se degradan energéticamente
 cíclica
 no cíclica
 La clorofila se neutraliza

22.  Transporte de electrones
cíclica
◦ Electrones del fotosistema I regresan
al fotosistema I
◦ Se genera ATP por quimiosmosis
◦ No NADPH, no O2

23. Light-dependent reactions Carbon fixation reactions
ATP
ADP
NADPH
NADP+
Light
reactions
Calvin
cycle
H2O O2
CO2
Chloroplast
Carbohydrates

24. Light-dependent reactions
(in thylakoids)
Carbon fixation reactions
(in stroma)
ATP
ADP
NADPH
NADP+
Light
reactions
Calvin
cycle
H2O O2 CO2
Chloroplast
Carbohydrates

25.  Transporte de electrones no
cíclica
◦ Se forma ATP y NADPH
◦ Electrones energizados por luz son
aceptados por NADP+
◦ Una serie de reacciones redox
◦ Electrones que provienen de P680
son reemplazados por los que
provienen del H2O
◦ Ocurre fotolisis

26. H2O -- ½ O2 + 2H+ 2e_

27. Oxidation- reduction potential (volts) (relative energy level)
Primary
electron
acceptor
Primary
electron
acceptor
NADPH
NADP+
ATP
H2O
O2
ADP
1
2
Photosystem II(P680)
Production
of ATP by
chemiosmosis
H+
Ferredoxin
Plastiquinone
Cytochrome
complex
Plastocyanin
1/2 + 2 H+
Pi
A0
A1
FeSx
FeSB
FeSA
(from medium)
Photosystem I(P700)
Electron
transport
chain
Electron
transport
chain
2e-
2 e

28. ETC
Energy from energized
electrons powers active
transport of H+ by ETC.
Figure 7-8 (part 2) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
C3
cycle
PSII PSI
stroma
ETC
thylakoid space
Energy from
energized
electrons powers
NADPH synthesis.
Flow of H+ down
concentration gradient
powers ATP synthesis.
High H+ concentration
generated by active
transport.
H+ channel coupled
to ATP-synthesizing
enzyme.
Energy-carrier
molecules power
the C3 cycle.

29.  Síntesis de ATP y transporte de
electrones
◦ Electrones se mueven en cadena de
electrones
◦ Protones (H+) se mueven de la
estroma hacia el lumen del tilacoide,
creando un gradiente de protones

30. stroma
Figure E7-2 (part 2) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
thylakoid
membrane
photosystem II
2e–
ADP ATP
P
Active transport
of hydrogen ions.
High H+ concentration
in thylakoid space.
H+ ion channel coupled
to ATP synthesizing
enzyme.
Flow of H+ powers
ATP synthesis.

31.  ATP se utilizan en estroma
 NADPH se utiliza en estroma
 O2 se libera al aire

33. Stroma
Thylakoid lumen
Thylakoid membrane Photons (H+)

34. Light-dependent reactions Carbon fixation reactions
ATP
ADP
NADPH
NADP+
Light
reactions
Calvin
cycle
H2O O2
CO2
Chloroplast
Carbohydrates

35.  Fijación del Carbono
◦ Se forma carbohidrato a partir de
CO2 , ATP, y NADPH
12 NADPH + 18 ATP + 6 CO2 →
C6H12O6 + 12 NADP + + 18 ADP + 18 Pi + 6 H2O

36.  Fases del ciclo de Calvin
◦ capturar CO2
◦ reducción del carbono
◦ regeneración de RuBP

37. PGA
G3P
Figure 7-12a Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
CO2
C3 plants use the C3 pathway
bundle-sheath
cells
In a C3 plant, mesophyll cells
contain chloroplasts; bundle-sheath
cells do not.
Much photorespiration
occurs under hot, dry
conditions.
CO2
rubisco
Little glucose
is synthesized.
O2
RuBP
glucose
within mesophyll chloropast
stoma
C3
Cycle

38. CO 2 molecules are
captured by RuBP,
resulting in an unstable
intermediate that is
immediately broken
apart into 2 PGA
12 molecules of
phosphoglycerate
(PGA)
12 ATP
12 ADP
PGA is phosphorylated
by ATP and reduced by
NADPH. Removal of a
phosphate results in
formation of G3P.
1
Through a series of
reactions G3P is
rearranged into new
RuBP molecules or
another sugar
6 ADP
ATP
P P
6 molecules of ribulose
phosphate (RP)
Glucose and other
carbohydrate synthesis
6 molecules of
ribulose bisphosphate
(RuBP)
2 molecules
of glyceraldehyde-3-
phosphate (G3P)
CALVIN
CYCLE
Carbon
reduction
phase
RuBP
regeneration
phase
CO2 uptake
phase
12 NADPH
6 molecules of CO2
10 molecules
of G3P
P
P
P
P
P
P
12 molecules
of glyceraldehyde-3-
phosphate (G3P)
3
2
12 NADP+