P. 96
IN
• Fill in the blanks to complete the reaction:
6__ __2 + 6__2__
Light
Chlorophyll
C__H__O__ + 6__2
• Name the reactants and the products in order
Remember this?


The light from the sun
is a special form of
electromagnetic
energy.
We call it the visible
light spectrum – think
of a rainbow
Draw a model to explain where the mass of the tree
came from as the acorn grows into a tree.
The ultimate
source of energy
on planet earth
is the sun!



A.
Chloroplasts
Green organelle in a
plant cell
2. Stroma –
fluid-filled inner space
3. Thylakoids Internal disk like
membranes within
stroma
 Organized into stacks Look like
poker
called grana.
chips
 Embedded with
special proteins
called pigments.
1.
How do plants absorb light?
Well, Not all of the light from the Sun makes it
to the surface of the Earth.
Not only that but, plants don’t use all the
available light. They mostly absorb red and
blue wavelengths.
You end up seeing the wavelengths (colors)
that plants reflect.
A.
4. Plant Pigments

C.
D.
E.
Pigments are special
proteins that absorb solar
energy.
Accessory pigments are
always in plants.
Chlorophyll is more
abundant during
warmer weather with a
lot of sunlight.
In fall, cool weather and
less daylight causes
chlorophyll to break
down and the other
pigments show
through.
Major pigments in plants are
chlorophyll a and chlorophyll b
Both absorb violet, blue, and red
wavelengths best.
2. Most green is reflected back.
1.
Accessory pigments capture light that
chlorophyll cannot.
B.
1.
Carotinoids = yellow-orange pigments
; absorb light in violet, blue, and green
regions
2.
Xanthophylls = red and yellow
pigments, do not absorb light as well
3.
Anthocyanins = red, purple, or blue
pigments; absorb green light.
Read ME 
When a colored chemical sample is placed
on a filter paper, the colors separate from
the sample by placing one end of the
paper in a solvent. The solvent diffuses
up the paper, dissolving the various
molecules in the sample according to the
polarities (opposite end charges) of the
molecules and the solvent.
If the sample contains more than one
color, that means it must have more than
one kind of molecule, the chances are very
high that each molecule will have at least
a slightly different polarity, giving each a
different solubility. The more soluble a
molecule is, the higher it will migrate up
the paper.
Look at the leaf you chose : what pigments
might do you see? What pigments might
be hidden?
Paper
Chromatography
LAB
A. Sunlight provides energy to Autotrophs
(producers) to make carbohydrates and
oxygen.
B. The photosynthesis Equation shows how:
6CO2 + 6H2O


Light
Chlorophyll
 producers are the ultimate source of
food for life
 Photosynthetic organisms produced
the oxygen in Earth’s atmosphere
(stromatolites).
C6H12O6 + 6O2
Carbon dioxide and water (6CO2 +
6H2O) are taken from environment.
The atoms are rearranged to form
glucose and oxygen (C6H12O6 + 6O2).
A. Glucose
 Some converted into energy for growth and
reproduction
 Some turned into starch or cellulose.
B. Starch
 many glucose monomers linked together
 stores chemical energy in the form of
chemical bonds.
C. Cellulose
 many glucose monomers linked together
 Provide support and strength within leaves
and stems.
 Also known as fiber.
 indigestible by humans but serves as a good
scrubbing agent to clean out our colons!
A. Photosynthesis doesn’t occur all at once it occurs in two
parts:
1. Light dependent (light) reactions (in thylakoids)
 Produces oxygen & ATP
 Uses water
2. Light independent (dark) reactions = Calvin Cycle
(in stroma)
 Uses carbon dioxide
 Produces glucose
B.
Light dependent (light) reactions
1. E from sunlight is transferred to electrons in
chlorophyll.
2. E level of e ̄ raised higher; they jump up to
higher energy level.
4. e ̄ lost from chlorophyll
replaced by splitting
water.
H2O broken into
hydrogen ions, electrons,
and oxygen atoms
 Electrons replace those
lost to chlorophyll
 The oxygen atoms form
O2 as a waste product –
supply most O2 in
atmosphere

3. Excited electrons are
unstable and want to
get rid of energy:
 Release E as heat
 Release E as
fluorescence (we
can’t see it)
 Eventually leave
chlorophyll; they are
accepted by a special
carrier molecule
(NADPH)
 The carrier molecule
brings it to stroma to
aide in Calvin cycle
(dark) reactions.
They’re
called dark
reactions
because they
do not use
light energy

C. Light Independent Reactions (dark) = (Calvin
Cycle)
1. Use chemical (ATP & NADPH) energy not light
energy
2. CO2 removed from air is used in a series of
continuous reactions.
3. 6 CO2 make one 6 Carbon glucose
Factors that influence the rate
(speed) of photosynthesis
1. Light
 Brighter light = faster rate =
more O2 produced
 Many plants spread out their
leaves to maximize the
amount of light falling on
them
 Too much light at a high
intensity can damage
chloroplasts.
 Shade plants
photosynthesize better in
dim light
A.
Draw graph at
bottom of notes
2. Temperature
 Higher the
temperature = faster
rate = more O2
 Temperatures above
40°C = enzymes
denatured = slower
rate
 Cold temperature =
enzymes move too
slowly for a reaction
to occur.
3. Carbon Dioxide
 increase in the concentration
of carbon dioxide = faster
rate of photosynthesis
Draw graph at
bottom of notes
No matter how much light is
increased the rate will not increase
after the plateau on the graph. Unless
another factor increases
Draw graph at
bottom of notes
You can
add more
heat
Or
more
CO2
P. 96
Add to your model to better explain where the mass
of the tree came from as the acorn grows into a tree.
Read me  - sustainability link!
Many crops such as tomatoes and lettuce give higher
yield when grown in greenhouses. Farmers add
additional carbon dioxide into the greenhouse to
increase the concentration and so the rate of
photosynthesis of the crops.
Some companies have used this to great
environmental use. Rather than pump waste carbon
dioxide into the atmosphere as a pollutant they
redirect it into big greenhouses where plants such as
tomatoes use it during photosynthesis. This not only
reduces their carbon footprint but gives an
additional profitable product.
In 1600, a Dutch scientist did an experiment to answer this question.