S.HS.3.5.2
The student understands the Sun
is the primary source of energy for life
through the process of photosynthesis

What is
Photosynthesis?
The process of
photosynthesis is a
series of chemical
reactions. -For
living organisms it is
the most important
chemical reaction on
our planet

What is the equation for the
chemical reaction for
photosynthesis?
chlorophyll
enzymes
The equation
described:
Chlorophyll
enzymes

6 CO2 + 6 H2O → C6H12O6 + 6 O2
Low energy

Low energy
High energy
Low energy
Six molecules of carbon dioxide react with six
molecules of water to form 1 molecule of
glucose and six molecules of oxygen.
Energy moves through the
food chain from life form to
life form. The first step is
photosynthesis in which the
sun's radiant energy, that
pours onto the earth
everyday, is turned into
carbohydrate(C6H12O6)
molecules. These
carbohydrates are used by
nearly all living things as fuel
for energy, and as building
blocks to biosynthesize larger
molecules such as
polysaccharides, protein,
nucleic acids and lipids.
DESCRIBE
PHOTOSYNTHESIS






It is the process of changing light energy to chemical
energy stored as sugar
It occurs in plants and algae
Plants need light energy, CO2, and H2O
It takes place in the thylakoids of chloroplasts,
Chlorophyll the green pigment in plants is used to
absorb wavelengths of light
2 stages: light dependent and Calvin Cycle or light
independent
WHAT HAPPENS DURING
PHOTOSYNTHESIS?



Plants capture light energy and use that
energy to make glucose
Sunlight provides the energy needed
by chlorophyll to change molecules of
carbon dioxide and water into glucose
Oxygen is also released in this reaction
CONTINUED……




Carbon dioxide enters the leaf through pores called
stomata
CO2 combines with the stored energy in the
chloroplasts through chemical reactions to make
glucose
The sugar is moved through cells in the leaf to the
roots, stems and fruits of the plants
Some of the sugar is used right away by the plant for
energy; some is stored as starch; and some is built
into plant tissue
WHY IS THIS IMPORTANT TO
US?

We cannot make our
own food (glucose,
energy), we must
get our food from
plants. Plants are
the first step in the
food chain.
PATH OF ENERGY


The flow of energy through life is a one-way
process. Energy is not recycled. It is eventually lost
as heat to space. Energy passes through the food
chain. The lower on the food chain/trophic level, the
more energy is available.
As energy moves up the food chain there is less and
less of it to go around. That's the main reason there
aren't as many big fierce predators (lions and tigers
and bears-Oh my!) compared to the herbivores
(mice, rabbits and deer). Not enough energy for
them!
TROPHIC LEVELS!

The plants only get a small
amount of the solar energy
that hits the earth.
And....
The herbivores only get
a little bit of the energy that
hits the plants.
And....
The carnivores and
decomposers only get a
little bit of the energy that
was eaten by the herbivores.
Only 10% energy is
gained each trophic level
Why is this important to us?


Do you breathe?
The oxygen released
during
photosynthesis is
necessary for most
living things.
WHY OXYGEN IS
IMPORTANT?

Oxygen is not just used by our bodies
for respiration. It's not just in the air.
It's the most abundant element on
earth. And about 65 percent of the
mass of your body is oxygen.
QUESTIONS



1. What is the term for the transfer of
energy and matter within a food web?
2. The first stage of photosynthesis in a
chloroplast is?
3. Which molecule in plant cells first
captures the radiant energy from
sunlight?
ANSWERS



1. A food web showing the tropic levels
and where energy is transferred
2. Light Dependent Reaction
3. Chlorophyll pigment
QUESTIONS



4. Photosynthesis uses sunlight to convert
water and carbon dioxide into?
5. A student is collecting gas given off from a
plant in bright sunlight at a temperature of 27
°C. The gas being collected is?
6. If carbon dioxide is removed from a plant’s
environment, what would you expect to
happen?
ANSWERS



4. Oxygen and Sugars
5. Oxygen
6. No sugars would be produced
Prepared are two beakers with identical sprigs of water plants as
shown. One was placed in the shade and the other by a lamp.
Then the distance of the beakers from the lamp was changed.
Bubbles were counted given off by each plant. Read the graph.

7.
QUESTIONS

7. If the student later tested the
bubbles collected in the test tube, what
would she find they are made of? How
do you know?
8. At what distance from the light
source was the greatest number of
bubbles produced per minute?
9. What do the student’s data show?
ANSWERS



7. Oxygen because release oxygen gas
during the first stage of photosynthesis
8. 5 cm-closest to the light source
9. The closer to the light source the
more oxygen bubbles produced.