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PHOTOSYNTHESIS
What do you need for
Photosynthesis?
Four things are needed for photosynthesis:
SUNLIGHT
Gives the plant energy
CHLOROPHYLL
WATER
Travels up from the
roots
CARBON DIOXIDE
Enters the leaf through small holes on the
underneath (stoma)
The green
pigment where
the chemical
reactions
happen
PHOTOSYNTHESIS
What does photosynthesis
make?
PHOTOSYNTHESIS
Oxygen
(waste)
Food for plant
(glucose)
PHOTOSYNTHESIS
water + Carbon dioxide
sugar +Oxygen
PHOTOSYNTHESIS
The sun
Oxygen
(waste)
Carbon dioxide from
the air
Food for plant (glucose)
Water from the soil
Where does
PHOTOSYNTHESIS take
place?
vacuole
Cell wall
nucleus
Chloroplasts!!
Cell
membrane
Plant Cell
PHOTOSYNTHESIS
Chloroplasts are the GREEN parts of a
plant cell.
They contain a chemical called
CHLOROPHYLL.
Chlorophyll is a catalyst.
A catalyst speeds up a
chemical reaction, but
doesn’t get used itself.
Checking for Understanding
• In which organelle or
cell structure does
photosynthesis
occur?
A. cell wall
B. cell membrane
C. Golgi apparatus
D. chloroplast
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
Energy and Living Things
• Autotrophs
organisms that can
make their own
energy or food
Energy and Living Things
• Heterotrophs
organisms that
must obtain energy
or food from other
organisms
Checking for Understanding
• What’s the ultimate source of energy
for plants?
• How do heterotrophs obtain energy?
Photosynthesis
• The key cellular process that produces
energy.
• Autotrophs like plants use energy from
sunlight to convert water, carbon
dioxide into oxygen and high energy
carbohydrates.
What plants do
6CO2 + 6H2O 
C6H12O6 + 6O2
Carbon dioxide plus water in the
presence of sunlight yield
sugars/carbohydrates and oxygen.
Checking for Understanding
• In addition to
chlorophyll and light,
photosynthesis
requires
A. water and oxygen
B. water and sugars
C. oxygen and CO2
D. Water and CO2
• The products of
photosynthesis are
A. sugars and oxygen
B. sugars and CO2
C. water and CO2
D. hydrogen & oxygen
How plants do it, an overview.
• The capture the energy of the sunlight
with absorbing pigments.
• Pigments are housed within plant cell
organelles
– Chloroplasts
• Most common plant pigment is
CHLOROPHYLL
Hopefully now you
can be like
this student.
And not
like this
one!