REACTIONS of PHOTOSYNTHESIS

Research into PHOTOSYNTHESIS began centuries ago with this simple question: When a tiny seed grows into a huge plant, where does all the “new plant” come from?

EXPERIMENTS TO FIND OUT Then he planted the seedling in the pot and watered it regularly. At the end of 5 years the _____________ __________about 75 kg, but the mass of the _________ was almost ________________. He decided the “increase in plant” had to come from the ________… that was the only thing he had added! In a Belgian physician ___________________ determined the mass of a pot of dry soil and a small seedling.

EXPERIMENTS TO FIND OUT Plants use _______ and ______ dioxide to make ___________________ Van Helmont didn’t realize the major contribution to the mass of his tree was something he couldn’t see… __________________ from the air.

EXPERIMENTS TO FIND OUT An English minister, _________________________, discovered that a flame burning in a closed jar would die out. If he placed a __________ in the jar and allowed a few days to pass, the candle could be lit again. The plant produced something “required for burning” that the candle used up We now know it was …____________

EXPERIMENTS TO FIND OUT Dutch scientist ________________________ showed Priestley’s plant experiment only worked if the plant was exposed to _________________ !

EXPERIMENTS TO FIND OUT American chemist ________________________ received the Nobel prize for figuring out the chemical _______________ used by plants to make sugar

THE BIG PICTURE These experiments led to work by later scientists who finally discovered that in the presence of light, plants transform CO 2 and water into carbohydrates and release oxygen. _____________ + ____________ _______________ + ____________ →

In addition to water and carbon dioxide, __________________ and __________________ are needed for photosynthesis to happen.

____________________ involves a complex series of chemical reactions, in which the product of one reaction is _____________ by the next reaction. Reaction 1 →Product → X Reaction 2 → Product Y A series of reactions linked in this way is referred to as a __________________________

See a video about PHOTOSYNTHESIS 8B

PHOTOSYNTHESIS Light-Dependent Reaction Light-Independent Reactions Light & Water oxygen ATP NADPH Carbon Dioxide (CH 2 O) n Calvin Cycle

PHOTOSYNTHESIS: Reactants & Products LIGHT ENERGY 6CO 2 + 6H 2 OSUGAR + 6O 2

Visible light is made up of many different _______________of light Your eyes “see” different sizes of waves as different ___________

Many people think that plants are green because they absorb and use green light in photosynthesis, BUT.... Myth: Image from:

BUT… We “see” reflected light Light wavelengths that are ___________ off of objects bounce back to our eyes. That is the ___________ we “see” Image modified from:

This book “looks BLUE” because the dye in this cover _______________ of the wavelengths of light _________ blue. _______ light is ____________ to your eyes and it looks BLUE

The dye in this T shirt absorbs all of the colors __________________________ Red wavelengths are _________________ to your eyes and the shirt looks RED GO CATS!

Objects “look BLACK” because black dye ________________ of the wavelengths of light. When wavelengths are absorbed so is the_____________ of the wave. That is why wearing a black T-shirt in the summer feels warmer than wearing a white t-shirt.

The dye in white objects _____________ of the wavelengths of light. ____ energy is ABSORBED so wearing white clothing is “cooler”. LITTLE

Which wavelengths of light are these Flowers REFLECTING? Images by: VanderWal

Image by: VanderWal Which wavelengths of light do these LEAVES reflect? So green leaves ____________ the green wavelength of light.

Plants gather the sun’s energy with light absorbing molecules called ___________. By: VanderWal

The main energy absorbing molecule in green plants is ___________________ _________________ are plant pigments too. (These look yellow, orange, and red)

GREEN leaves have BOTH chlorophyll AND carotenoids __________________ but the huge amount of chlorophyll ______ the other colors and leaves usually look green

In ______, chlorophyll production slows as the trees shut down and photosynthesis stops for winter.

Then we can see the carotinoid colors that are usually _______ by chlorophyll

red Chlorophyll a Chlorophyll b Absorption of Light by Chlorophyll a and Chlorophyll b © Pearson Education, Inc. Publishing asPearson Prentice-Hall. All rights reserved. There are two types of chlorophyll __________________ & ___________________ Chlorophyll a absorbs the _____ & ________ wavelengths best. It absorbs very little ______ light.

red Chlorophyll a Chlorophyll b Absorption of Light by Chlorophyll a and Chlorophyll b © Pearson Education, Inc. Publishing asPearson Prentice-Hall. All rights reserved. There are two types of chlorophyll __________________ & ___________________ Chlorophyll b absorbs some ______light and even more _________ light.

red Chlorophyll a Chlorophyll b Absorption of Light by Chlorophyll a and Chlorophyll b © Pearson Education, Inc. Publishing asPearson Prentice-Hall. All rights reserved. NEITHER KIND OF CHLOROPHYLL IS VERY GOOD AT ABSORBING _________ LIGHT!

That’s why leaves LOOK GREEN….. Chlorophyll doesn’t absorb…. it ___________ GREEN light!

That’s why plant have other pigments (like carotenoids). They help _________ some wavelengths chlorophyll _______; so the plant can __________ of the sun’s energy.

Chlorophyll a Chlorophyll b Absorption of Light by Chlorophyll a and Chlorophyll b © Pearson Education, Inc. Publishing asPearson Prentice-Hall. All rights reserved. SO WHAT WAVELENGTHS ARE BEST FOR PHOTOSYNTHESIS? THE ONES CHLOROPHYLL ABSORBS THE BEST ________ and _______________

Pearson Education Inc, Pusblishing as Pearson Prentice Hall Because light is a form of ___________, any molecule that absorbs light also ___________the energy from the light.

ENERGY & ELECTRONS When chlorophyll absorbs light, the energy is transferred to electrons in the chlorophyll molecule. HIGH ENERGY ____________ make photosynthesis work!