Photosynthesis: The Hill Reaction

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

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 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 -It include two major stages 1)Light reactions -it generate energy carrier molecules ATP and NADPH -it occur in the thylakoids (Grana) - Hill Reaction

Photosynthesis 2) Dark reactions or Calvin-Benson cycle - it generate C-C covalent bonds of carbohydrates -it occur in the stroma of the chloroplast

Photosynthesis

Chloroplast

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

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.

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. Inchlorophyllthylakoid eukaryotes Photosystem I uses P700 and Photosystem II uses P680. -P700 chlorophyll is sensitive to light energy in slightly longer wavelength

Light reactions -at which stage DCPIP intercept….. (5-2) -what will happen to the reaction….

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

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

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 Remember, our endpoint or what we are looking for is the spinach leaf disks to float or at least show indication the reaction started.

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