Photosynthesis presentation
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WENNY PINTALITNA (813 617 4032) RENDY M LANZA ( 813 617 4025)
FACULTY OF MATHEMATICS AND NATURAL SCIENCESTATE UNIVERSITY OF MEDAN
2013
PROSES FOTOSINTESISPROSES FOTOSINTESIS PADA TUMBUHAN PADA TUMBUHAN
Wenny Pintalitna (813 617 4032)
Rendy M Lanza (813 617 4025)
PASCA SARJANA PENDIDIKAN BIOLOGI FACULTY OF MATHEMATICS AND FACULTY OF MATHEMATICS AND NATURAL SCIENCENATURAL SCIENCE
STATE UNIVERSITY OF MEDANSTATE UNIVERSITY OF MEDAN20132013
Food Chain
Different wavelengths of visible light are seen by the human eye as different colors.
WHYWHY ARE ARE PLA PLANTS NTS GREGREEN?EN?
Gammarays
X-rays UV Infrared Micro-waves
Radiowaves
Visible light
Wavelength (nm)
Sunlight minus absorbed Sunlight minus absorbed wavelengths or colors wavelengths or colors equals the apparent color equals the apparent color of an object.of an object.
The feathers of male cardinals are loaded with carotenoid pigments. These pigments absorb some wavelengths of light and reflect others.
Reflected light
Why are plants green?
Reflected lig
ht
Transmitted light
• Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water
AN OVERVIEW OF PHOTOSYNTHESIS
Carbondioxide
Water Glucose Oxygengas
PHOTOSYNTHESIS
• 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
LightChloroplast
Lightreactions
Calvincycle
NADP
ADP+ P
• The light reactions convert solar energy to chemical energy– Produce ATP & NADPH
AN OVERVIEW OF PHOTOSYNTHESIS
• The location and structure of chloroplasts
LEAF CROSS SECTION MESOPHYLL CELL
LEAF
Chloroplast
Mesophyll
CHLOROPLAST Intermembrane space
Outermembrane
Innermembrane
ThylakoidcompartmentThylakoidStroma
Granum
StromaGrana
• Chloroplasts contain several pigments
Chloroplast Pigments
– Chlorophyll a – Chlorophyll b – Carotenoids
Figure 7.7
Chlorophyll a & b•Chl a has a methyl group •Chl b has a carbonyl group
Porphyrin ring delocalized e-
Phytol tail
Different pigments absorb light differently
Klorofil a
• Klorofil a adalah pigmen yang secara langsung berpartisipasi dalam reaksi terang
Ph
oto
n
Ph
oto
n
Water-splittingphotosystem
NADPH-producingphotosystem
ATPmill
• Two types of photosystems cooperate in the light reactions
• The O2 liberated by photosynthesis is made from the oxygen in water (H+ and e-)
Plants produce OPlants produce O22 gas by splitting H gas by splitting H22OO
Primaryelectron acceptor
Primaryelectron acceptor
Electron transport chain
Electron transport
Photons
PHOTOSYSTEM I
PHOTOSYSTEM II
Energy forsynthesis of
by chemiosmosis
Noncyclic Photophosphorylation • Photosystem II regains electrons by splitting
water, leaving O2 gas as a by-product
Cyclic Photophosphorylation • Process for ATP generation • Reaction Center => 700 nm
2 H + 1/2
Water-splittingphotosystem
Reaction-center
chlorophyll
Light
Primaryelectronacceptor
Energyto make
Electron transport chain
Primaryelectronacceptor
Primaryelectronacceptor
NADPH-producingphotosystem
Light
NADP
1
23
How the Light Reactions Generate ATP and NADPH
• 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
In the light reactions, electron transport In the light reactions, electron transport chains generate ATP, NADPH, & Ochains generate ATP, NADPH, & O22
• 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
Chemiosmosis powers ATP synthesis in the light reactions
The production of ATP by chemiosmosis in photosynthesis
LIGHTREACTOR
NADP+
ADP
ATP
NADPH
CALVINCYCLE
[CH2O] (sugar)STROMA(Low H+ concentration)
Photosystem II
LIGHT
H2O CO2
Cytochromecomplex
O2
H2OO2
1
1⁄2
2
Photosystem ILight
THYLAKOID SPACE(High H+ concentration)
STROMA(Low H+ concentration)
Thylakoidmembrane
ATPsynthase
PqPc
Fd
NADP+
reductase
NADPH + H+
NADP+ + 2H+
ToCalvincycle
ADP
PATP
3
H+
2 H++2 H+
2 H+
• A Photosynthesis Road Map
Chloroplast
Light
Stack ofthylakoids ADP
+ P
NADP
Stroma
Lightreactions
Calvincycle
Sugar used for
Cellular respiration Cellulose
Starch
Other organic compounds
Calvin Cycle
(G3P)
Input(Entering one
at a time)CO2
3
Rubisco
Short-livedintermediate
3 P P
3 P P
Ribulose bisphosphate(RuBP)
P
3-Phosphoglycerate
P6 P
6
1,3-Bisphoglycerate
6 NADPH
6 NADPH+
6 P
P6
Glyceraldehyde-3-phosphate(G3P)
6 ATP
3 ATP
3 ADP CALVINCYCLE
P5
P1
G3P(a sugar)Output
LightH2O CO2
LIGHTREACTION
ATP
NADPH
NADP+
ADP
[CH2O] (sugar)
CALVINCYCLE
O2
6 ADP
Glucose andother organiccompounds
Phase 1: Carbon fixation
Phase 2:Reduction
Phase 3:Regeneration ofthe CO2 acceptor(RuBP)
Siklus Calvin
• Dimulai dari CO2 dan menghasilkan Glyceraldehyde 3-phosphate
• Tiga bagian siklus Calvin menghasilkan 1 produk molekul
• Tiga tahap– Fiksasi karbon– Reduksi CO2– Regenerasi RuBP
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 3-phosphoglycerate
2 Tiap molekul 3-phosphoglycerate menerima tambahan grup fosfat membentuk 1,3-Bisphosphoglycerate (fosforilasi ATP)
• NADPH dioksidasi dan elektron yang ditransfer ke 1,3-Bisphosphoglycerate memecah molekul dengan tereduksi menjadi Glyceraldehyde 3-phosphate
3 Tahap terakhir dari siklus ini adalah regenerasi RuBP
• Glyceraldehyde 3-phosphate dikonversi menjadi RuBP melalui sebuah seri reaksi yang melibatkan fosforilasi molekul oleh ATP
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 tempat-tempat dengan konsentrasi CO2 yang tinggi
Jalur Tumbuhan C3
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
Jalur Tumbuhan C4
• Anatomi daun C4 dan jalur C4
CO2
Mesophyll cell
Bundle-sheathcell
Vein(vascular tissue)
Photosyntheticcells of C4 plantleaf
Stoma
Mesophyllcell
C4 leaf anatomy
PEP carboxylase
Oxaloacetate (4 C) PEP (3 C)
Malate (4 C)
ADP
ATP
Bundle-Sheathcell CO2
Pyruate (3 C)
CALVINCYCLE
Sugar
Vasculartissue
CO2
Comparison between C3 and C4 LeafC3 dan C4
• 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
• Jalur CAM mirip dengan jalur C4
Spatial separation of steps. In C4 plants, carbon fixation and the Calvin cycle occur in differenttypes of cells.
(a) Temporal separation of steps. In CAM plants, carbon fixation and the Calvin cycle occur in the same cellsat different times.
(b)
PineappleSugarcane
Bundle-sheath cell
Mesophyll Cell
Organic acid
CALVINCYCLE
Sugar
CO2 CO2
Organic acid
CALVINCYCLE
Sugar
C4 CAM
CO2 incorporatedinto four-carbonorganic acids(carbon fixation)
Night
Day
1
2 Organic acidsrelease CO2 toCalvin cycle
Factors Affecting Photosynthesis Rate
• Intensitas CahayaLaju fotosintesis maksimum ketika banyak cahaya.
• Konsentrasi Karbon DioksidaSemakin banyak karbon dioksida di udara, makin banyak jumlah bahan yang dapat digunakan tumbuhan untuk melangsungkan fotosintesis.
• SuhuEnzim-enzim yang bekerja dalam proses fotosintesis hanya dapat bekerja pada suhu optimalnya.
• Kadar airKekeringan menyebabkan stomata menutup - menghambat penyerapan karbon dioksida - mengurangi laju fotosintesis.
•Kadar fotosintat (hasil fotosintesis)Jika kadar fotosintat seperti karbohidrat berkurang, laju fotosintesis akan naik.
•Tahap pertumbuhanPenelitian 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.