Photosynthesis in Overview Process by which plants and other autotrophs store the energy of sunlight into sugars. The energy from the sun is converted into the chemical energy of glucose. Requires sunlight, water, and carbon dioxide. Overall equation: 6 CO2 + 6 H20  C6H12O6 + 6 O2 Occurs in the leaves of plants in organelles called chloroplasts.

Chloroplast Structure Inner membrane of the thylakoid is called the thylakoid membrane. Thickened regions called thylakoids. A stack of thylakoids is called a granum. (Plural – grana) Stroma is a liquid surrounding the thylakoids.

Photosynthesis: The Chemical Process Occurs in two main phases. 1. ‘Light’ Dependent Reactions. 2. Light Independent Reactions (aka – the Calvin Cycle, Dark reactions). Light reactions are the “photo” part of photosynthesis. Light is absorbed by pigments. Dark reactions are the “synthesis” part of photosynthesis. Glucose is produced during this stage.

The Reactions of Photosynthesis THE LIGHT DEPENDENT REACTIONS THE LIGHT INDEPENDENT REACTIONS Occurs in the grana (thylakoid) Occurs in the stroma AKA: light reactions AKA: dark reactions, calvin cycle and carbon fixation reactions Uses light and water Uses carbon dioxide, ATP, NADPH Produces oxygen, ATP, NADPH Produces glucose Photolysis occurs (photochemical rxns) Cyclical reactions begin & end with RuBP Provides atmospheric oxygen Sugar produced is used for cellular respiration Requires enzymes Dependent upon light Not dependent upon light ATP and NADPH produced here energize the dark reactions ATP and NADPH from light reactions energize these dark reactions Occur in the chloroplast

Light Dependent Reactions Light-dependent reactions occur in the grana. Light and water are required for this process. Energy molecules are formed. (ATP and NADPH). These molecules power the dark reactions. Photolysis occurs. This is the splitting of water molecules. Oxygen gas is made as a waste product.

Light Independent Reactions Dark reactions (light-independent) occur in the stroma. ATP and NADPH molecules created during the light reactions power the production of glucose. Carbon dioxide is “fixed” into Phosphoglyceraldehyde (PGAL). 2 PGAL’s come together to form glucose.

Pigments Chlorophyll A is the most important photosynthetic pigment. Green! Other pigments accessory pigments are also present in the leaf. Chlorophyll B (yellow-green) Carotenoids (yellow-orange). Xanthophylls (yellow).

Chromatography A technique used to separate the component parts of a mixture according to how well each part dissolves within a solvent. The more soluble a part is, the farther it will travel up the chromatography paper. Allows scientists to observe parts of a mixture that they would otherwise be unable to see.

Do Now Wash hands. Wash test tube and flask at your desktops. Put all materials away and tucked under your desk with the exception of a pencil, pen and lab packet. Lab # 9: Analysis of Plant Pigments

Do Now Follow lab steps a through d. Raise your hand for plant pigment solution. Complete steps e through h.

Do Now Get a pair of goggles. Get solvent from Mrs. Muraco Follow steps j and k. Be sure to record the time.

Do Now Step m. Record the time. Answer questions 3-9. Complete calculations. Fill in table. Answer 1-3. Label pigments and Rf values and hand in lab.