reactions of photosynthesis 8-2. review before you start
TRANSCRIPT
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