Photosynthesis Anabolic reaction of converting light energy into chemical energy and storing it for use in the form of chemical bonds found in glucose or glucose polymers. Takes place in photosynthetic plants, protists and cyanobacteria.

Leaf of Plant Chlorophyll found in chloroplast in cells of leaf. Most concentrated in palisade layer of leaf.

Light Energy Visible light- wave lengths of about 300 to 700 angstroms of the electromagnetic spectrum. Wave lenghth = distance from one crest to the next crest in a wave.

Visible Light Made up of violet,indigo, blue, green, yellow, orange, and red wave lengths. Violet is shortest- ultraviolet is below it. Red is longest- infrared is above it.

Other parts of electromagnetic spectrum Gamma rays X-rays Microwaves Radio waves Color seen is color that is not absorbed by pigment and reflected back to the eye. In other words, if you see green, it’s because All other colors in the spectrum are absorbed, Except green, so that’s what gets reflected back

Light Dependent Reaction of Photosynthesis Converts light energy into chemical energy Takes place in photosynthetic membrane in chloroplast. Membrane is called a thylakoid membrane and a stack of them is a granum.

Chlorophyll Green pigment molecules imbedded in thylakoid membranes in groups called Photosystems I and II. Pigment is any chemical that absorbs or reflects light wavelengths. When pigment absorbs light, electrons are excited- have extra energy- and escape the chlorophyll molecule.

Role of Water in Photosynthesis Escaping electrons are used to provide the energy for a chemiosmosis system for the production of ATP. Hydrogen atoms are broken from a water molecule leaving oxygen as a waste product. If no water- no light reaction-no photosynthesis.

Electron Movement Hydrogen atom splits into electron and H+ Hydrogen electrons replace electrons lost from chlorophyll in Photosystem II. Electrons from PSII travel to PSI and replace those electrons lost.

Chemiosmosis Energy from this pathway is used to pump H+ into center of thylakoid membrane. ATP made when H+ pass back through membrane . H+ atoms accepted by NADP to form NADPH.

Dark Reaction, Calvin Cycle, or Light Independent Reaction. Takes place in liquid part of chloroplast or stroma. Takes ATP and H+ from NADPH and converts carbon dioxide into a stored form of sugar through a series of cyclical steps.

Regulation and control Cycle is controlled by enzyme Rubisco. Process must be completed 6 times in order to make one molecule of glucose. Amount of carbon dioxide, ATP and NADPH controls process.

Calvin Cycle Steps RuBP already present in stroma. RuBP is a five carbon compound. Carbon dioxide attaches to RuBP to make an unstable six carbon compound. This 6 carbon compound gets broken into two - 3 carbon compounds.

3 carbon compound undergoes a series of changes to become PGAL. Out of every 12 molecules of PGAL produced, 2 are turned into glucose, and 10 are turned in more RuBP ATP and H are added to each step transferring energy into a form that can be stored.

Without photosynthesis, energy could not be stored or converted. Plants do not make energy, but rather convert it into a stored form- glucose.