What are organelles?
PHOTOSYNTHESIS
Def: The process that uses the sun’s energy to
make simple sugars (food energy).
These sugars are then converted to complex
carbohydrates- starches, and stored.
Photosynthesis takes place inside the cell
organelle, chloroplasts, in the leaf of a plant.
The pigments (most commonly, chlorophyll) are in
the membrane of the thylakoid discs.
These are what absorb the sunlight.
Chlorophyll absorbs most wavelengths of light except
green.
Since green is not absorbed, it is reflected.
Some plants stop producing chlorophyll in their
leaves in the Fall, so other pigments become
visible.
Carbon Dioxide enters the plant leaf through
openings called stomata.
Water enters the plants through the roots and
travels upward to the leaves.
Once the plant has all three ingredients, a series
of chemical reactions take place in the
chloroplasts.
So, plants make the food energy (glucose) in the chloroplasts.
When they need to break down their own glucose to make
ATP, they use another organelle, the Mitochondria.
Cellular Respiration
Def: The process by which mitochondria break
down food energy molecules (like glucose) to
produce a chemical energy molecule called
ATP, is known as cellular respiration.
Animals breathe in the
oxygen released during
Photosynthesis, and when
we eat autotrophs, we take
in the glucose made….and
the starch that was stored.
OXYGEN
GLUCOSE
Photosynthesis
Cellular Respiration
Cellular respiration is also carried out by
mitochondria in animal cells.
We use food energy and oxygen
and create
CO2 , water, and ATP (chemical energy)
Cellular Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + 36ATP
Glucose
Oxygen Gas
Carbon Dioxide
Water
Energy
It is the reverse process of photosynthesis
COMPARING PHOTOSYNTHESIS AND
CELLULAR RESPIRATION:
Comparison of Photosynthesis and Cellular Respiration
Photosynthesis
Food synthesized
Cellular Respiration
Energy from sun stored in glucose
Food broken down
Energy in glucose released
Carbon dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Occurs only in presence of
chlorophyll
Occurs in all living cells