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THE SUN: MAIN SOURCE OF
The
sun transfers
ENERGY
FOR LIFEits
ONenergy
EARTHto
the earth
and from there it can be
transferred
and transformed.
Photo-synthesis
means "putting together with light."
Plants use sunlight to turn water and carbon dioxide into
glucose. Glucose is a form of sugar.
Plants use glucose as food for energy and as a building block
for growing.
Autotrophs make glucose and
Heterotrophs are consumers of it.
Why is Photosynthesis important?
Makes organic molecules (glucose) out of inorganic
materials (carbon dioxide and water).
It begins all food chains/webs. Thus all life is
supported by this process.
It also makes oxygen gas!!
Photosynthesis-starts to ecological food chains
which will become food webs!
Photosynthesis in Stages
Glucose provides the energy and
carbon needed to make other
plant materials like wax and
proteins.
The photograph
below is an elodea
leaf at 400X.
Individual cells are
clearly visible. The
tiny green structures
within the cells are
chloroplasts
this is where
photosynthesis
happens.
• In plants and simple animals, waste products are removed by diffusion.
Plants, for example, excrete O2, a product of photosynthesis.
Stoma
This opening how plants exchange gases!
Can you name the two important gases
that go in and out of the leaves?
Why are the stomata
located on the
underside of leaves?
Chloroplasts
producing
oxygen!
WHY ARE PLANTS GREEN?
It's not that easy bein' green
Having to spend each day the color of the leaves
When I think it could be nicer being red or yellow or gold
Or something much more colorful like that…
Kermit the Frog
Leaves are green because
they contain
the green pigment:
chlorophyll
Leaves have a large surface
area to absorb as much light
as
"Thanks for the Glucose!"
possible
• Why do we see green?
• Green color from white light
reflected NOT absorbed
• Chloroplast: organelle
responsible for
photosynthesis
• Chlorophyll: located within
Chloroplast
• Green pigment
Why are plants green?
EQUATION FOR PHOTOSYNTHESIS
Reactants
Products
WATER
6CO2 + 6H2O +ENERGY
CARBON
DIOXIDE
OXYGEN
C6H12O6 + 6O2
GLUCOSE
Close up on a plant cell:
Why are chloroplasts near the cell membrane and cell wall?
Why do the chloroplasts circulate around the edges of the plant cell?
Four factors affect photosynthesis:
1. Light – if there is more light
photosynthesis happens faster
2. Water – if there is not enough water
photosynthesis slows down
3. Temperature – the best temperature is
about 300C – anything above 400C will
slow photosynthesis right down
4. CO2 – if there is more carbon
dioxide photosynthesis will
happen quicker