REACTIONS of PHOTOSYNTHESIS

8-2

REVIEW BEFORE YOU START

Atoms that have gained or lost electrons have anelectric charge andare called__________

They are writtenwith a + or –next to theirsymbol

IONS Na+

Cl-

1.____________2.____________3.____________4.____________5.____________6.____________

Atoms/ions important for living things

Carbon - C

Oxygen - OHydrogen - HNitrogen - NSulfur - S

Phosphorus - P

ATOMS CAN JOIN TOGETHER TO MAKE MOLECULES

Ex: Joining 2 HYDROGEN

atoms with 1 OXYGEN atom makes ________

WATER

A chemical formula tells what kind of molecules and how many are in a molecule

EX: ________H2O

________________ = kind of chemical reaction in which molecules are produced by joining smaller molecules together

2 H2 + O2 → 2 H20

SYNTHESIS

2 water molecules

Hydrogen molecule oxygen molecule

An chemical equation tells what happens in a chemical reaction when molecules interact.

NaOH + HCl → NaCl + H20

______________ _______________Molecules that react Molecules that are

produced

products→reactants

Chemical reactions need help to get started

EX: A fire needs a match to get it started.

IT’S LIKE PUSHING A SNOWBALL UP A HILL . . . Once you get it up there, it can roll down by itself

In living systems ___________ called __________ help chemical reactionshappen.

ENZYMESPROTEINS

PROTEINS ACT AS ENZYMES

ENZYMES fit together with _____________ (reactants) like a lock and key to form an____________________________.

__________are released and enzyme is free to help again

SUBSTRATES

ENZYME-SUBSTRATE COMPLEX

PRODUCTS

Many enzyme NAMES end in _____and the beginning of the name tells what it doesDNA Polymerase= “polymerizes” joins monomers to make DNA

Protease= breaks down proteins

ATP synthase= synthesizes ATP

-ASE

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 1643-a Belgian physician ___________________ determined the mass of a pot of dry soil and a small seedling.

Jan van Helmont

seedling hadgained

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 hecouldn’t see…__________________ from the air.carbon dioxide

water carbonCarbohydrates

EXPERIMENTS TO FIND OUT1771- 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

1779-

Dutch scientist ________________________

showed Priestley’s plant experiment only

worked if the plant was exposed to _________________ !

Jan Ingenhousz

light

EXPERIMENTS TO FIND OUT

1961- 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 CO2 and water

into carbohydrates and release oxygen.

_____________ + ____________ _______________ + ____________

Carbondioxide WATER Sugars Oxygen

6 CO2_____________ + ____________ _______________ + ____________6 H2O C6H12O6 6 O2→

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

Calvin Cycle

C6H12O6

PHOTOSYNTHESIS: Reactants & Products

LIGHT ENERGY

6CO2 + 6H2O SUGAR + 6O2

http://www.ology.amnh.org/einstein/lightmatterenergy/light.html

Visible light is made up of many different_______________of light

Your eyes “see”different sizes ofwaves as different ___________

http://www.simontucket.com/_Portfolio/PortLarge/L_Il_Prism.jpg

wavelengths

colors

Many people think that plants are green because they absorb and use green light in photosynthesis,

BUT . . . .

Myth:

BUT… We “see” reflected light

Light wavelengths that are ___________

off of objects bounce back to our eyes .

That is the ___________ we “see”

REFLECTED

COLOR

This book “looks BLUE” because the dye in this cover _______________ of the wavelengths of light _________ blue.

_______ light is ____________ to your eyes and itlooks BLUE

exceptabsorbs ALL

BLUEreflected

The dye in this T shirt absorbs all of thecolors __________________________

Red wavelengths are_________________ to your eyes and theshirt looks RED

except red

reflected

Objects “look BLACK” because blackdye ________________ of thewavelengths of light.

When wavelengths are absorbed so is the_____________ of the wave.

That is why wearing a blackT-shirt in the summer feelswarmer than wearing a white t-shirt.

absorbs ALL

ENERGY

The dye in white objects _____________ of the wavelengths of light.

_______ energy is ABSORBED so wearing whiteclothing is “cooler”.

REFLECTS ALL

LITTLE

Which wavelengths of light are these Flowers REFLECTING?

yellowPurple & yellow

green

Which wavelengths of light do these LEAVES reflect?

So green leaves____________ thegreen wavelength of light.

REFLECT

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

pigments

The main energy absorbing moleculein 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 thecarotinoid colors that are usually _______ by chlorophyllHIDDEN

red

Chlorophyll a

Chlorophyll b

Absorption of Light byChlorophyll a and Chlorophyll b

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 byChlorophyll a and Chlorophyll b

There are two types of chlorophyll__________________ & ___________________

Chlorophyll babsorbs some ______light and even more_________ light.

Chlorophyll a Chlorophyll b

red

Blue-violet

red

Chlorophyll a

Chlorophyll b

Absorption of Light byChlorophyll a and Chlorophyll b

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 byChlorophyll a and Chlorophyll b

SO WHAT WAVELENGTHS ARE BEST FOR PHOTOSYNTHESIS?

THE ONESCHLOROPHYLLABSORBS THE BEST________ and_______________

red

Blue-violet

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 transferredto electrons in the chlorophyll molecule.

HIGH ENERGY ____________make photosynthesis work!

ELECTRONS