REACTIONS of PHOTOSYNTHESIS

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. Jan van Helmont seedling had gained soil unchanged WATER

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. carbon dioxide watercarbon Carbohydrates

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 …____________ OXYGEN Joseph Priestley live plant

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

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

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. _____________ + ____________ _______________ + ____________ Carbon dioxide WATERSugars Oxygen 6 CO 2 _____________ + ____________ _______________ + ____________ 6 H 2 OC 6 H 12 O 6 6 O 2 →

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

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

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 ___________ wavelengths colors

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: REFLECTED COLOR

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 except absorbs ALL BLUE reflected

The dye in this T shirt absorbs all of the colors __________________________ Red wavelengths are _________________ to your eyes and the shirt looks RED except red reflected 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. absorbs ALL ENERGY

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

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

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

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

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

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

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

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

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. Chlorophyll a Chlorophyll b red violet Blue

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. Chlorophyll a Chlorophyll b red Blue-violet

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! GREEN

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

That’s why plant have other pigments (like carotenoids). They help _________ some wavelengths chlorophyll _______; so the plant can __________ of the sun’s energy. USE MORE ABSORB DOESN’T

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 _______________ red Blue-violet

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 ABSORBS

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