Almost all plants are photosynthetic autotrophs, as are some bacteria and protists
-
Upload
maralah-wilson -
Category
Documents
-
view
29 -
download
0
description
Transcript of Almost all plants are photosynthetic autotrophs, as are some bacteria and protists
![Page 1: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/1.jpg)
• Almost all plants are photosynthetic autotrophs, as are some bacteria and protists– Autotrophs generate their own organic matter through
photosynthesis– Sunlight energy is transformed to energy stored in the
form of chemical bonds– Why are plants green?
(a) Mosses, ferns, andflowering plants
(b) Kelp
(c) Euglena (d) Cyanobacteria
THE BASICS OF PHOTOSYNTHESIS
![Page 2: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/2.jpg)
Light Energy Harvested by Plants & Other Photosynthetic Autotrophs
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
![Page 3: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/3.jpg)
• Photosynthesis is the process by which ______________organisms use light energy to make sugar and oxygen gas from carbon dioxide and water
AN OVERVIEW OF PHOTOSYNTHESIS
Carbondioxide
Water Glucose Oxygengas
PHOTOSYNTHESIS
![Page 4: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/4.jpg)
• The Calvin cycle makes:
LightChloroplast
Lightreactions
Calvincycle
NADP
ADP+ P
• The light reactions:
AN OVERVIEW OF PHOTOSYNTHESIS
![Page 5: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/5.jpg)
Chloroplasts: Sites of Photosynthesis
• Photosynthesis– Occurs in chloroplasts, organelles in certain
plants– All green plant parts have chloroplasts and carry
out photosynthesis• The leaves have the most chloroplasts• The green color comes from chlorophyll in the
chloroplasts• The pigments absorb light energy
![Page 6: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/6.jpg)
• In most plants, photosynthesis occurs primarily in the leaves, in the chloroplasts
• A chloroplast contains: – stroma, a fluid – grana, stacks of thylakoids
• The thylakoids contain chlorophyll– Chlorophyll is the green pigment that captures
light for photosynthesis
Photosynthesis occurs in chloroplastsPhotosynthesis occurs in chloroplasts
![Page 7: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/7.jpg)
• The location and structure of chloroplasts
LEAF CROSS SECTION MESOPHYLL CELL
LEAF
Chloroplast
Mesophyll
CHLOROPLAST Intermembrane space
Outermembrane
Innermembrane
ThylakoidcompartmentThylakoidStroma
Granum
StromaGrana
![Page 8: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/8.jpg)
• Chloroplasts contain several pigments
Chloroplast Pigments
– Chlorophyll a – Chlorophyll b – Carotenoids
Figure 7.7
![Page 9: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/9.jpg)
Different pigments absorb light differently
![Page 10: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/10.jpg)
Excitedstate
e
Heat
Light
Photon
Light(fluorescence)
Chlorophyllmolecule
Groundstate
2
(a) Absorption of a photon
(b) fluorescence of isolated chlorophyll in solution
Excitation of chlorophyll in a chloroplast
Loss of energy due to heat causes the photons of light to be less energetic.
Less energy translates into longer wavelength.
Energy = (Planck’s constant) x (velocity of light)/(wavelength of light)
Transition toward the red end of the visible spectrum.
e
![Page 11: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/11.jpg)
Cyclic Photophosphorylation • Process for ATP generation associated with
some Photosynthetic Bacteria• Reaction Center => 700 nm
![Page 12: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/12.jpg)
Ph
oto
n
Ph
oto
n
Water-splittingphotosystem
NADPH-producingphotosystem
ATPmill
• Two types of photosystems cooperate in the light reactions
![Page 13: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/13.jpg)
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
![Page 14: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/14.jpg)
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
![Page 15: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/15.jpg)
• 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 ___________________
In the light reactions, electron transport In the light reactions, electron transport chains generate ATP, NADPH, & Ochains generate ATP, NADPH, & O22
![Page 16: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/16.jpg)
• 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 _____________________– In the stroma, the H+ ions combine with NADP+
to form ________________
Chemiosmosis powers ATP synthesis in the light reactions
![Page 17: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/17.jpg)
• The production of ATP by chemiosmosis in photosynthesis
Thylakoidcompartment(high H+)
Thylakoidmembrane
Stroma(low H+)
Light
Antennamolecules
Light
ELECTRON TRANSPORT CHAIN
PHOTOSYSTEM II PHOTOSYSTEM I ATP SYNTHASE
![Page 18: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/18.jpg)
• A Photosynthesis Road Map
Chloroplast
Light
Stack ofthylakoids ADP
+ P
NADP
Stroma
Lightreactions
Calvincycle
Sugar used for
Cellular respiration Cellulose
Starch
Other organic compounds
![Page 19: Almost all plants are photosynthetic autotrophs, as are some bacteria and protists](https://reader036.fdocuments.net/reader036/viewer/2022062309/56813733550346895d9ec15b/html5/thumbnails/19.jpg)
Review: Photosynthesis uses light energy to make food molecules
Light
Chloroplast
Photosystem IIElectron transport
chains Photosystem I
CALVIN CYCLE Stroma
Electrons
LIGHT REACTIONS CALVIN CYCLE
Cellular respiration
Cellulose
Starch
Other organic compounds
• A summary of the chemical processes of photosynthesis