Transcript Photosynthesis

PHOTOSYNTHESIS
Engage
Essential Question
Explain
Engage
 List
10 things that you used today that
depend upon photosynthesis.
 Think hard and record your list on your
hand-out. This is an individual activity.
Possible answers




Did you list items like the
plants that you ate?
What about the clothing
that you are wearing?
The bed or pillow that you
slept on?
The fuel that heated your
water, your stove,
microwave, vehicle?
What about…
Oil
Medicine
Coal
Essential Question
What materials
does a seed need…
To develop
into a tree?
Explore: van Helmont’s Willow
experiment of 1648

I have learned from this experiment that all Vegetables do immediately,
and materially proceed out of the Element of water only. For I took an
Earthen vessel, in which I put 200 pounds of Earth that had been dried
in a Furnace, which I moistened with Rainwater, and I implanted therein
the Trunk or Stem of a Willow Tree, weighing five pounds; and at
length, five years being finished, the Tree sprung from thence, did
weigh 169 pounds, and about three ounces: But I moistened the
Earthen Vessel with Rain-water and it was large, and implanted into the
Earth, and least the dust that flew about should be co-mingled with the
Earth, I covered the lip or mouth of the Vessel with an Iron-Plate
covered with Tin, and easily passable with many holes. I computed not
the weight of the leaves that fell off in the four Autumns. At length, I
again dried the Earth of the Vessel, and there were found the same two
hundred pounds, wanting about two ounces. Therefore 164 pounds of
Wood, Barks, and Roots, arose out of water only.
Explain
Take into account van Helmont’s results and
revisit your previous list of materials that you
believed a seed needs to develop into wood.
 Consider whether van Helmont’s conclusion
that only water is needed to produce plant
biomass is justified. If not, why not.

PHOTOSYNTHESIS
Photosynthesis is the ability of a plant to
turn sunlight, air, and water into sugar
(energy).
 The overall reaction is:

CO2 +
light
chlorophyll
H2O -------> C6H12O6
{Carbon dioxide} + {Water}

yields
{sugar}
+
+ O2
{Oxygen}
Photosynthesis is vital to life for two
reasons…
–1. The oxygen in the air comes from
photosynthesis. The plants continue to
replenish the oxygen in the air.
–2. All of our food comes directly or
indirectly from photosynthesis.
Where does
Photosynthesis
Occur?
Photosynthesis
Steps
Carbon
Dioxide
#1 Light
Dependent
Reactions
ADP + P
NADP+
ATP
ADP: Adenosine
#2
Calvin
Cycle
Water
Sunlig
ht
ATP:
Adenosine
TriPhosphate
NADPH
Oxygen
Di-Phosphate
Glucose
Where are chloroplasts
located?
Chloropla
st
Stomata
Light is captured by pigments- molecules
that absorb specific wavelengths of light.
The main photosynthetic pigment is
chlorophyll.
Chlorophyll absorbs most wavelengths
of light except green. Green is what is
reflected which is why this pigment
appears green.
Trapping Energy from Sunlight


Light-dependent
Reactions – convert
light energy into
chemical energy
(Electron Transport
Chain)
Light-independent
Reactions – the
molecules of ATP
produced in lightdependent reactions
produce the simple
sugars (Calvin Cycle)
What controls photosynthesis?
Intensity
of light
Scarcity of water
Level of CO2
Your Assignment
 http://www.newtonsapple.tv/video.php?i
d=915

It is the year 2040 and you are a research scientist.
The amount of sunlight that reaches the earth has been
reduced because of some major event like pollution,
volcanoes or global fires.
Farmers are asking you for help to save their failing crops.
Figure out ways that you might help.
 Complete
the chloroplast assignment
before the next class.