1. PROSES FOTOSINTESIS
PADA TUMBUHAN
Wenny Pintalitna (813 617 4032)
WENNY PINTALITNA (813 617 4032)
Rendy M Lanza (813 617 4025)
RENDY M LANZA ( 813 617 4025)
PASCA SARJANA PENDIDIKAN BIOLOGI
FACULTY OF MATHEMATICS AND
FACULTY OF MATHEMATICS AND NATURAL SCIENC
NATURAL SCIENCE
STATE UNIVERSITY OF MEDAN
STATE UNIVERSITY OF MEDAN
2013
2013

2. Food Chain

3. WHY ARE PLANTS GREEN?
Different wavelengths of visible light are seen by
the human eye as different colors.
Gamma
rays
X-rays
UV
Infrared
Visible light
Wavelength (nm)
Microwaves
Radio
waves

4. The feathers of male cardinals
are loaded with carotenoid
pigments. These pigments
absorb some wavelengths of
light and reflect others.
gh
ed l i
t
eflec
R
t
Sunlight minus absorbed
wavelengths or colors
equals the apparent color
of an object.

5. Why are plants green?
d
cte
e
efl
R
h
lig
t
Transmitted light

6. AN OVERVIEW OF PHOTOSYNTHESIS
• Photosynthesis is the process by which
autotrophic organisms use light energy to
make sugar and oxygen gas from carbon
dioxide and water
Carbon
dioxide
Water
Glucose
PHOTOSYNTHESIS
Oxygen
gas

7. AN OVERVIEW OF PHOTOSYNTHESIS
• The light reactions
convert solar
energy to chemical
energy
Light
Chloroplast
NADP+
ADP
+P
– Produce ATP & NADPH
• The Calvin cycle makes
sugar from carbon
dioxide
– ATP generated by the light
reactions provides the energy
for sugar synthesis
– The NADPH produced by the
light reactions provides the
electrons for the reduction of
carbon dioxide to glucose
Light
reactions
Calvin
cycle

8. • The location and structure of chloroplasts
Chloroplast
LEAF CROSS SECTION
MESOPHYLL CELL
LEAF
Mesophyll
CHLOROPLAST
Intermembrane space
Outer
membrane
Granum
Grana
Stroma
Inner
membrane
Stroma
Thylakoid
Thylakoid
compartment

9. Chloroplast Pigments
• Chloroplasts contain several pigments
– Chlorophyll a
– Chlorophyll b
– Carotenoids
Figure 7.7

10. Chlorophyll a & b
•Chl a has a methyl
group
•Chl b has a carbonyl
group
Porphyrin ring
delocalized e-
Phytol tail

11. Different pigments absorb light
differently

12. Klorofil a
• Klorofil a adalah pigmen
yang
secara
langsung
berpartisipasi dalam reaksi
terang

13. • Two types of
photosystems
cooperate in the
light reactions
Photon
Photon
ATP
mill
Water-splitting
photosystem
NADPH-producing
photosystem

14. Plants produce O2 gas by splitting H2O
• The O2 liberated by photosynthesis is made
from the oxygen in water (H+ and e-)

15. Noncyclic Photophosphorylation
• Photosystem II regains electrons by splitting
water, leaving O2 gas as a by-product E
Primary
electron acceptor
Primary
electron acceptor
El
ec
tro
n
tra
ns
p
or
t
ch
ai
l ec
tro
n
tra
ns
po
rt
n
Photons
Energy for
synthesis of
PHOTOSYSTEM I
PHOTOSYSTEM II
by chemiosmosis

16. Cyclic Photophosphorylation
• Process for ATP generation
• Reaction Center => 700 nm

17. How the Light Reactions Generate ATP and NADPH
Primary
electron
acceptor
Energy
to make
Primary
electron
acceptor
NADP+
3
2
Light
Ele
c
Light
t ro
nt
r an
sp
o rt
ch
ai n
Primary
electron
acceptor
1
Reactioncenter
chlorophyll
Water-splitting
photosystem
2 H+ + 1/2
NADPH-producing
photosystem

18. In the light reactions, electron transport
chains generate ATP, NADPH, & O2
• Two connected photosystems collect
photons of light and transfer the energy to
chlorophyll electrons
• The excited electrons are passed from the
primary electron acceptor to electron
transport chains
– Their energy ends up in ATP and NADPH

19. Chemiosmosis powers ATP
synthesis in the light reactions
• The electron transport chains are arranged
with the photosystems in the thylakoid
membranes and pump H+ through that
membrane
– The flow of H+ back through the membrane is
harnessed by ATP synthase to make ATP
– In the stroma, the H+ ions combine with NADP+ to
form NADPH

20. The production of ATP by chemiosmosis in
photosynthesis
H2O
CO2
LIGHT
NADP+
ADP
LIGHT
REACTOR
CALVIN
CYCLE
ATP
NADPH
STROMA
(Low H+ concentration)
O2
[CH2O] (sugar)
Cytochrome
complex
Photosystem II
Photosystem I
NADP+
reductase
Light
2 H+
3
Fd
NADPH
Pq
+ H+
Pc
2
H2O
THYLAKOID SPACE
(High H+ concentration)
NADP+ + 2H+
1
1
⁄2
O2
+2 H+
2 H+
To
Calvin
cycle
STROMA
(Low H+ concentration)
Thylakoid
membrane
ATP
synthase
ADP
ATP
P
H
+

21. • A Photosynthesis Road Map
Chloroplast
Light
Stroma
NADP+
Stack of
thylakoids
ADP
+P
Light
reactions
Calvin
cycle
Sugar used for
•
•
•
•
Cellular respiration
Cellulose
Starch
Other organic compounds

22. Calvin Cycle
Light
H2O
CO2
Input
(Entering one
3
CO2 at a time)
NADP+
ADP
LIGHT
REACTION
CALVIN
CYCLE
ATP
NADPH
O2
Rubisco
[CH2O] (sugar)
Phase 1: Carbon fixation
3 P
3 P
P
Short-lived
intermediate
P
Ribulose bisphosphate
(RuBP)
P
6
3-Phosphoglycerate
6 ATP
6 ADP
CALVIN
CYCLE
3 ADP
3
ATP
6 P
P
1,3-Bisphoglycerate
6 NADPH
Phase 3:
Regeneration of
the CO2 acceptor
5
(RuBP)
6 NADPH+
6 P
P
(G3P)
6
P
Glyceraldehyde-3-phosphate
(G3P)
1
P
G3P
(a sugar)
Output
Glucose and
other organic
compounds
Phase 2:
Reduction

23. Siklus Calvin
• Dimulai dari CO2 dan
menghasilkan
Glyceraldehyde 3phosphate
• Tiga bagian siklus Calvin
menghasilkan 1 produk
molekul
• Tiga tahap
– Fiksasi karbon
– Reduksi CO2
– Regenerasi RuBP

24. 1 Sebuah molekul CO2
dikonversi dari bentuk
inorganiknya menjadi
molekul organik (fixation)
melalui pengikatan ke
gula 5C (ribulose
bisphosphate atau
RuBP).
– Dikatalisasi oleh enzim
RuBP carboxylase
(Rubisco).
• Bentuk gula 6C pecah
menjadi 3phosphoglycerate

25. 2 Tiap molekul 3phosphoglycerate
menerima tambahan
grup fosfat membentuk
1,3-Bisphosphoglycerate
(fosforilasi ATP)
• NADPH dioksidasi dan
elektron yang ditransfer
ke 1,3Bisphosphoglycerate
memecah molekul
dengan tereduksi
menjadi Glyceraldehyde
3-phosphate

26. 3 Tahap terakhir dari
siklus ini adalah
regenerasi RuBP
• Glyceraldehyde 3phosphate
dikonversi menjadi
RuBP melalui
sebuah seri reaksi
yang melibatkan
fosforilasi molekul
oleh ATP

27. Tanaman C3 dan C4
a)
Tanaman C3
–
CO2 dapat langsung
masuk ke dalam siklus
Calvin sehingga
membentuk
gliseraldehid 3 fosfat
yang memiliki 3
molekul karbon
–
Tanaman C3 umumnya
terdapat di tempattempat dengan
konsentrasi CO2 yang
tinggi

28. Jalur Tumbuhan C3

29. b) Tanaman C4
 Musim panas penguapan besar - CO2
dalam jumlah sedikit fotosintesis dapat
terhenti.
 Enzim modifikasi CO2
menjadi okasaloasetat
tersebih dulu sebelum
masuk ke dalam siklus
Calvin.
 Contoh: alang-alang,
jagung dan tebu

30. Jalur Tumbuhan C4

31. • Anatomi daun C4 dan jalur C4
Photosynthetic
cells of C4 plant
leaf
Mesophyll
cell
Mesophyll cell
Bundlesheath
cell
CO
CO2 2
PEP carboxylase
PEP (3 C)
Oxaloacetate (4 C)
ADP
Vein
(vascular tissue)
Malate (4 C)
ATP
C4 leaf anatomy
BundleSheath
cell
Pyruate (3 C)
CO2
Stoma
CALVIN
CYCLE
Sugar
Vascular
tissue

32. Comparison between C3 and C4 Leaf
C3 dan C4

33. • Tanaman CAM
– Malam hari, respirasi tidak sempurna.
– KH diubah menjadi asam malat, CO2 tidak
dilepaskan, pH tetap tinggi (7), pati dalam sel
penjaga dihidrolisis menjadi gula, Ψs nya
menurun, terjadi endoosmosis, Ψp sel
penjaga naik, turgor, dinding sel penjaga
tertekan ke arah luar, stomata membuka.
• Selama siang hari, stomata tertutup
– CO2 dilepaskan dari asam organik untuk
digunakan dalam siklus Calvin

34. • Jalur CAM mirip dengan jalur C4
Pineapple
Sugarcane
C4
Mesophyll Cell
Organic acid
Bundlesheath cell
(a) Spatial separation of
steps. In C4 plants,
carbon fixation and the
Calvin cycle occur in
different
types of cells.
CALVIN
CYCLE
Sugar
CAM
CO2
1 CO2 incorporated
into four-carbon
organic acids
(carbon fixation)
2
Organic acids
release CO2 to
Calvin cycle
CO2
Organic acid
Night
Day
CALVIN
CYCLE
Sugar
(b) Temporal separation of
steps. In CAM plants,
carbon fixation and the
Calvin cycle occur in the
same cells
at different times.

35. Factors Affecting Photosynthesis Rate
• Intensitas Cahaya
Laju fotosintesis maksimum ketika banyak cahaya.
• Konsentrasi Karbon Dioksida
Semakin banyak karbon dioksida di udara, makin banyak
jumlah bahan yang dapat digunakan tumbuhan untuk
melangsungkan fotosintesis.
• Suhu
Enzim-enzim yang bekerja dalam proses fotosintesis hanya
dapat bekerja pada suhu optimalnya.
• Kadar air
Kekeringan menyebabkan stomata menutup - menghambat
penyerapan karbon dioksida - mengurangi laju fotosintesis.

36. •Kadar fotosintat (hasil fotosintesis)
Jika kadar fotosintat seperti karbohidrat berkurang,
laju fotosintesis akan naik.
•Tahap pertumbuhan
Penelitian menunjukkan bahwa laju fotosintesis jauh
lebih tinggi pada tumbuhan yang sedang
berkecambah ketimbang tumbuhan dewasa
dikarenakan tumbuhan berkecambah memerlukan
lebih banyak energi dan makanan untuk tumbuh.