Photosynthesis:

• Light energy combines CO2 and H to make sugars.

• Performed by all photosynthetic autotrophs (photoautotrophs)– Cyanobacteria– Algae (and other protists)– plants

Relevance of photosynthesis

• Fixes carbon– Places carbon in a form that can be used by

organisms• Take carbon from inorganic molecules and puts it in organic

molecules (sugars)

– Base of food chain

• Removes CO2 from atmosphere

• Oxygenates the atmosphere

General Equation for Photosynthesis

CO2 + H20 ---------------- C6H12O6 + O2

• Substrate/inputs/starting materials• Obtained from environment • Products/ending materials

LightLight & pigment

Provides energy for process

Pigment = molecule that has color•Photosynthetic pigment absorbs light energy (capture light energy)•Absorbed light is captured•Non-absorbed light is reflected creating visible color of pigment

CHLOROPHYLL:IS MAIN PHOTOSYNTHETIC PIGMENT

General Equation for Photosynthesis

CO2 + H20 ----------- C6H12O6 + O2

• Substrate/inputs/starting materials• Obtained from environment • Products/ending materials

From Env:•Air•Water (that organisms lives in)

From Env:•Soil•Water (that organisms lives in)

Stays in organism•Broken down for energy•Used as building material

Released to Env.•Oxygenates air•Oxygenates water

General Equation for Photosynthesis

CO2 + H2O ----------- C6H12O6 + O2

White light is composed of many colors (wavelengths) of light mixed together

ROY G. BIVColor of pigment = color NOT absorbed

Absorbed v. reflected v. transmitted

Reflected light color of object (color object appears)

absorbed light energy captured my object/material

transmitted light also visible

The color you see is/are the reflected colors (wavelenths)

The colors you do NOT see are absorbed

Pigment absorption

A

B

What you should know• What kinds of organisms perform photosynthesis• The ecological relevance/importance of photosynthesis• The general equation for photosynthesis (including what are the starting and ending

materials)• Where each molecule involved comes from or what is done with it after it is created• How the atoms in the substrates and rearranged to make the products• The colors of the visible spectrum• The relationship between absorbed and reflected light and the color an object

appears and how much energy is made available for photosynthesis• What an accessory pigment is and why they are advantageous.• What wavelengths/colors of light chlorophyll absorbs (including which color(s) it

absorbs best/most)• How the experiment worked and the relationship the class determined existed

between light intensity and photosynthetic rate• Why co2 rich soln was used, why the heat shield was used.

HOW PLANTS WORK• Use Water (from ground), CO2, and sunlight energy to make food• WATER + CO2 SUGARS

– this is photosynthesis– This happens mostly in leaves (which also lose water)