1. REACTIONS of PHOTOSYNTHESIS 8-2

2. REVIEW BEFORE YOU START

3. Atoms that have gained or lost electrons have an electric charge and are called __________
They are written with a + or – next to their symbol + Na
IONS - Cl

4. Atoms/ions important for living things
____________
Carbon - C
Oxygen - O
Hydrogen - H
Nitrogen - N
Sulfur - S
Phosphorus - P

5. 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

6. ________________ = kind of chemical reaction in which molecules are produced by joining smaller molecules together
2 H2 + O2 → 2 H20
SYNTHESIS
Hydrogen molecule
oxygen molecule
2 water molecules

7. An chemical equation tells what happens in a chemical reaction when molecules interact.
NaOH + HCl → NaCl + H20
______________ _______________
Molecules that react Molecules that are
produced →
reactants
products

8. 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

9. In living systems ___________ called __________ help chemical reactions
happen.
PROTEINS
ENZYMES

10. PROTEINS ACT AS ENZYMES
ENZYMES fit together with _____________ (reactants) like a lock and key to form an
____________________________.
SUBSTRATES
ENZYME-SUBSTRATE COMPLEX
PRODUCTS
__________are released
and enzyme is free to
help again

11. -ASE
Many enzyme NAMES end in _____
and the beginning of the name tells what it does
DNA Polymerase= “polymerizes”
joins monomers to make DNA
Protease=
breaks down proteins
ATP synthase= synthesizes ATP

12. 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?

13. EXPERIMENTS TO FIND OUT
a Belgian physician ___________________ determined the mass of a pot of dry soil
and a small seedling.
Jan van Helmont
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 ________________.
seedling had
gained
soil unchanged
He decided the “increase in plant” had to come from
the ________… that was the only thing he had added!
WATER

14. EXPERIMENTS TO FIND OUT
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
Plants use _______ and ______ dioxide to make ___________________
water
carbon
Carbohydrates

15. EXPERIMENTS TO FIND OUT
1771- 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.
Joseph Priestley
live plant
The plant produced something
“required for burning” that the candle used up
OXYGEN
We now know it was …____________

16. EXPERIMENTS TO FIND OUT
1779-
Dutch scientist ________________________
showed Priestley’s plant experiment only
worked if the plant was exposed to _________________ !
Jan Ingenhousz
light

17. 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

18. 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.
Carbon dioxide
WATER
Sugars
Oxygen
_____________ + ____________ _______________ + ____________
6 CO2
6 H2O →
C6H12O6
6 O2
_____________ + ____________ _______________ + ____________

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

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

21. PHOTOSYNTHESIS Light-Dependent Reaction oxygen Light & Water
ATP
NADPH
Carbon Dioxide
Light-Independent Reactions
C6H12O6
Calvin Cycle

22. PHOTOSYNTHESIS: Reactants & Products
LIGHT ENERGY
6CO2 + 6H2O
SUGAR + 6O2

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

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

26. BUT… We “see” reflected light
Light wavelengths that are ___________
off of objects bounce back to our eyes .
That is the ___________ we “see”
REFLECTED
COLOR

27. absorbs ALL except BLUE reflected
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
absorbs ALL
except
BLUE
reflected

28. except red 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

29. absorbs ALL ENERGY 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

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

31. Which wavelengths of light are these
Flowers REFLECTING?
Purple & yellow
yellow

32. Which wavelengths of light do these LEAVES reflect? green
So green leaves ____________ the
green wavelength
of light.
REFLECT

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

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

35. 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

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

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

38. There are two types of chlorophyll
__________________ & ___________________
Chlorophyll a
Chlorophyll b
Absorption of Light by
Chlorophyll a and Chlorophyll b
Chlorophyll a
absorbs the
_____ & ________
wavelengths best.
It absorbs very
little ______ light.
violet
red
Chlorophyll b
Chlorophyll a
red
Blue

39. There are two types of chlorophyll
__________________ & ___________________
Chlorophyll a
Chlorophyll b
Absorption of Light by
Chlorophyll a and Chlorophyll b
Chlorophyll b
absorbs some
______light and
even more
_________ light.
red
Chlorophyll b
Chlorophyll a
Blue-violet
red

40. NEITHER KIND OF CHLOROPHYLL IS VERY GOOD AT ABSORBING _________ LIGHT!
Absorption of Light by
Chlorophyll a and Chlorophyll b
NEITHER KIND OF CHLOROPHYLL IS VERY GOOD AT ABSORBING _________ LIGHT!
Chlorophyll b
Chlorophyll a
GREEN
red

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

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

43. SO WHAT WAVELENGTHS ARE BEST FOR PHOTOSYNTHESIS?
Absorption of Light by
Chlorophyll a and Chlorophyll b
THE ONES CHLOROPHYLL ABSORBS
THE BEST
________ and
_______________
Chlorophyll b
Chlorophyll a
red
Blue-violet

44. Because light is a form of ___________, any molecule that absorbs light also ___________the energy from the light.
ENERGY
ABSORBS

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