Photosynthesis

Photosynthesis Photosynthesis = building glucose (chemical energy) by using the sun’s energy (electromagnetic energy) Occurs in the chloroplast means “green container” Uses sunlight, water, & CO2 Makes glucose (chemical energy) & oxygen (waste product)

Thylakoids – contain chlorophyll. Site of the light reaction. Stroma – watery space surrounding the thylakoid. Site of the DARK reaction. Granum – stack of thylakoids

Photosynthesis Equation REACTANTS PRODUCTS 6 CO2 + 6 H20 + sunlight  C6H12O6 + 6 O2 carbon dioxide + water + energy  glucose + oxygen

Composed of 2 main reactions Light Dependent Reaction Light Independent Reaction Calvin Cycle Dark Reaction

Light-Dependent Reaction The light phase Occurs in the Thylakoid membrane within in the Chloroplast What gets used: H2O (water – split into H2 and O) & sunlight What gets made: ATP (energy), NADPH (energy carrier) Oxygen is released as waste

Light-Independent Reaction Also know an the Calvin Cycle or Dark Reaction The “synthesis” phase Occurs in the Stroma within in the Chloroplast What gets used: CO2, ATP, NADPH What gets made: Glucose (C6H12O6)

Chloroplast Thylakoids e H2 \ O H2O NADP + H2 CO2 C6H12O6 Stroma

Factors Affecting Photosynthesis Light Intensity As light intensity increases, photosynthesis increases, to a certain point. Carbon Dioxide As CO2 increases, photosynthesis increases, to a certain point. Temperature All chemical reactions are dependent on temperature

Light Intensity CO2 Levels Temperature Rate of photo. Rate of photo. Rate of photo.

2 Concerns for plants Getting water & keeping water. Plants developed roots in order to get water and they developed a cuticle to keep water in the leaves. Cuticle: waxy covering that surrounds the leaf and reduces transpiration (water loss by plants).

Stomata Solved the problem! A stomata is a hole on the underside of a leaf that allows gas exchange. It is surrounded by guard cells. Reduces transpiration (water loss by leaves)

Plants need water for 2 reasons: For photosynthesis and plumps guard cells – open up and allow for gas exchange. Low water, guard cells may keep stomata closed. Stomata are open during the day when photosynthesis is happening. Stomata are closed at night when photosynthesis is not happening (& to reduce transpiration.)

FROOT LOOP KEY WINDOW SIDE DOOR SIDE PURPLE: OXYGEN GREEN: HYDROGEN RED: CARBON ORANGE: OXYGEN GREEN: HYDROGEN YELLOW: CARBON