PHOTOSYNTHESIS

I. Autotrophs and Heterotrophs SUN Energy for living things comes from the SUN A. Autotrophs- make their own food Ex: plants, some bacteria, protists

Heterotrophs- obtain it from the foods they consume » Ex: animals, some bacteria, protozoans (and even fungi!)

Sooo… food as energy is either MADE through photosynthesis or OBTAINED through consumption

II. Think about the Location of Photosynthesis…

= WATER

Other Important Parts Xylem: transports H 2 O Stoma: pore that allows gases to enter and exit

A.Double-membrane structure 1  outer membrane 2  inner membrane 3  granum (stack) 4  Thylakoid (individual) 5  Stroma (fluid) III. CHLOROPLAST STRUCTURE B. Internal Organization 1. Thylakoids: photosynthetic membranes that have clusters of chlorophyll and other pigments 2. Stroma: Fluid surrounding thylakoids

IV. Light & Pigments A. Sunlight is “white” but contains mixtures of visible wavelengths PIGMENTS B. Plants gather sun’s energy using light- absorbing molecules called PIGMENTS

C. Plant Pigments 1. Chlorophyll a - Absorbs all colors of light except green - Plays major role in light reactions of photosynthesis 2. Chlorophyll b - Yellow-green 3. Xanthophyll - In carotenoid family - Yellow 4. Carotene - Red & orange pigments MAJOR MINOR

Plant pigments absorb different wavelengths of energy- which wavelength is the LEAST absorbed?

Green is NOT absorbed!

1. Leaves blue-violet & red-orange light very well 2. Green light is REFLECTED why plants look green! ABSORB D. Wavelengths

V. PHOTOSYNTHESIS Inputs: Light, carbon dioxide, & water Outputs: sugar and oxygen

Photosynthesis Has Two Parts:

VI. Light Reaction 1.Chlorophyll captures light energy in chloroplast 2.This splits H 2 O into oxygen and hydrogen 3.Oxygen is a "waste product" & escapes to the atmosphere 4.Energy from the reaction is used in the next stage (Calvin Cycle).

B.ATP and NADPH (chemical energy) are recycled back into the system. C. Light reaction is charging up the “battery” needed to make “battery” needed to make sugars in Calvin Cycle sugars in Calvin Cycle

VII. Calvin Cycle A.Does NOT use light at all B.This is the process to use energy from Light Cycle to convert CO 2 into glucose

Reactants: Products: VIII.Overview of Photosynthesis

Two Processes Light Reaction Calvin Cycle

IX. Factors Affecting Photosynthesis Shortage of raw materialsShortage of raw materials TemperatureTemperature Light intensityLight intensity