photosynthesis
DESCRIPTION
Photosynthesis. Capturing Solar Energy. Overview of Photosynthesis. (glucose) Occurs in some bacteria or chloroplast of plants and protists Carbon dioxide (CO 2 ) is reduced to produce glucose - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/1.jpg)
Photosynthesis
Capturing Solar Energy
![Page 2: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/2.jpg)
Overview of Photosynthesis
(glucose)• Occurs in some bacteria or chloroplast of plants and
protists • Carbon dioxide (CO2) is reduced to produce glucose
• Energy required is captured from the sun by chlorophyll
• Photosynthesis has a Light reaction and a Dark reaction
![Page 3: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/3.jpg)
![Page 4: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/4.jpg)
Fig. 7.2
![Page 5: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/5.jpg)
![Page 6: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/6.jpg)
A more colorful photosynthesis Fig 6-7
![Page 7: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/7.jpg)
What is chlorophyll?Chloroplasts contain several pigments:
– Chlorophyll a– Chlorophyll b– Carotenoids
![Page 8: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/8.jpg)
Chlorophyll absorbs Red and Blue light from the visible spectrum but reflects Green light.
![Page 9: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/9.jpg)
Fig. 6-3
![Page 10: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/10.jpg)
Light absorption in photosynthetic bacteria (7.5)
![Page 11: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/11.jpg)
Light-Dependant Reaction• Occurs on thylakoid membranes of the
chloroplast• Only occurs in the presence of light• Two parts: Photosystems and Electron
Transport Chains (E.T.C.)• Transfers light energy to energy molecules –
ATP and NADPH
![Page 12: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/12.jpg)
Light Reaction (7.10)
![Page 13: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/13.jpg)
Photosystem II• Water loses 2 electrons and releases O2 .
• Light energizes the 2 electrons • e- passes through E.T.C. which produces ATP• ATP is carried over to the Calvin cycle
![Page 14: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/14.jpg)
Photosystem I• Electrons are energized again • Energized electrons bond with a proton and
NADP+ to form NADPH• NADPH is carried over to the Calvin Cycle.
![Page 15: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/15.jpg)
Light Reaction (7.14)
![Page 16: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/16.jpg)
Light Independent (Dark) Reaction• Doesn't require light.• Occurs in stroma of the chloroplast
![Page 17: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/17.jpg)
Calvin Cycle1. 6 CO2(1C) bonds with 6 RuBP(5C) and splits
to form 12 PGA (3C)2. ATP and NADPH (From Light Reaction)
reduces 12 PGA to 12 PGAL(3C)3. 2 PGAL forms Glucose (6C) (or other sugars)
remaining 10 form 6 RuP(5C)4. More ATP turns 6 RuP into 6 RuBP
![Page 18: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/18.jpg)
Dark Reaction
![Page 19: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/19.jpg)
Regulation of Photosynthesis
• Require CO2, H2O and Light
• Plants need to regulate the absorption of CO2 and H2O
• Stomata – openings allow CO2 in, O2 & H2O out.
![Page 20: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/20.jpg)
Stomata – open and close with the help of guard cells (NIB)
![Page 21: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/21.jpg)
Gas exchange (7.2)
![Page 22: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/22.jpg)
Some plants are specialized to survive in dry climates.
![Page 23: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/23.jpg)
Types of Plants
• C3 plants:– Use CO2 directly from the air
– Are very common and widely distributed
• C4 plants:– Close their stomata to save water during hot and
dry weather – Can still carry out photosynthesis
• CAM plants:– Are adapted to very dry climates – Open their stomata only at night to conserve water
![Page 24: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/24.jpg)
C4 and CAM (7.14)
![Page 25: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/25.jpg)
How much photosynthesis? (Do not copy)
• Photosynthetic organisms absorb more energy than humans consumes in a year
• In all, photosynthetic organisms convert around 104,900,000,000,000 Kg of carbon into organic compounds each year
• Bacteria have higher SA/V and consequently more efficient at absorbing light and producing glucose
![Page 26: Photosynthesis](https://reader035.vdocuments.us/reader035/viewer/2022062722/56813980550346895da11325/html5/thumbnails/26.jpg)
Photosynthesis Again