Photosynthesis: The Hill Reaction

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Photosynthesis The Hill Reaction
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Announcements
-There is a quiz next week that will cover
Fermentation and Photosynthesis. -home work is
posted on my web page as usual
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Photosynthesis

• -Process by which plants, and some bacteria use
  the
• energy from sunlight to produce sugar.
• Also, it is termed Carbon fixation.
• The overall equation is
• 6H2O 6CO2 ----------gt C6H12O6 6O2
• -It include two major stages
• 1)Light reactions
• -it generate energy carrier molecules
• ATP and NADPH
• -it occur in the thylakoids (Grana)
• - Hill Reaction

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Photosynthesis
2) Dark reactions or Calvin-Benson cycle -
it generate C-C covalent bonds of carbohydrates
-it occur in the stroma of the chloroplast
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Photosynthesis
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Chloroplast
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Wavelength and chlorophyll
White light can be separated into
different colors (wavelength) by passing it
through a prism. short wave length carry more
energy than long wave length
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Wavelength and chlorophyll
-chlorophyll is the green pigments common to
all photosynthetic cells, absorbs all wavelengths
of visible light except green. -chlorophyll a is
the one that exist in most plants.
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Wavelength and chlorophyll

• -chlorophyll and other light reaction chemicals
  are
• embedded in the thylakoids membrane.
• -chlorophyll a comes in two flavors P700 P680
• photosystems  are Clusters of several hundred
• molecules of chlorophyll in a thylakoid. In
• eukaryotes Photosystem I uses P700 and
• Photosystem II uses P680.
• -P700 chlorophyll is sensitive to light energy in
  
• slightly longer wavelength

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Light reactions
-at which stage DCPIP intercept.. (5-2) -what
will happen to the reaction.
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Light reactions
During electron transport, a proton gradient is
generate in the interior of the thylakoids
The proton gradient is used to generate ATP
through the ADP-ATP pump in a process known as
chemiosmotic coupling
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I got the picture

• we will determine which wavelength
• of light are effective in promoting
• photosynthesis by determining
• photosynthetic efficiency in the
• presence of differently dyed
• solutions of buffer.
• we will be using blue, green, yellow, and red
• Wavelength for different colors
• blue 430nm, green 520nm, yellow 520nm, and
• red 640nm

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I got the picture
-Also, we will examine the effect of some drugs
on the process of photosynthesis.
DCPIP---electron acceptor
---blue in oxidized state
---colorless in reduced state
Diuron---herbicide DBMIB---herbicide Rememb
er, our endpoint or what we are looking for is
the spinach leaf disks to float or at least show
indication the reaction started.
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I got the picture
-by the end of the experiment, you should be
able to figure out whether Diuron or DBMIB
intercept the reaction before or after DCPIP