Energy Transfer In Plants
Changing the Sun’s Energy Into
Useable, Stored Energy
All Life Needs Energy!!
 Some life uses a process called chemosynthesis to make
life possible.
 Bacteria can get energy from thermal vents on the ocean
floor!!!
 Hydrogen sulfide chemosynthesis CO2+O2+4{H2S}→CH2O+4{S}+3{H2O}
 But even this depends on photosynthesis!! (O2 from plants)
Chloroplast
Sunlight
Plant Cell
Parts of the Plant Cell
Life Needs Useable Energy
Remember!! ATP is
the useable form of
energy in a cell!
In order for a plant to
make ATP they must
perform 2 processes,
Photosynthesis &
Cellular Respiration
Plants Do BOTH!!
Photosynthesis with
Chloroplasts
And Cellular
Respiration with
Mitochondria
Where Does It Start?
Photosynthesis
begins with Sunlight,
when it hits the leaves
of plants (and some
protists or bacteria)
Photosynthesis has 3 stages
I. Capture Light Energy
II. Make Chemical Energy
III. Store Energy In Carbohydrates
Photosynthesis: Stage 1
Light hits the
chloroplast and is
absorbed by a
pigment called
chlorophyll
A pigment is any
light absorbing
substance
Stage 1: Continued
Sunlight
Chlorophyll
membrane of
chloroplast
{
e-
2 H2O
electron
4 H+
O2
In Stage 1, the
energy from the light
splits H2O into three
parts:
Oxygen (O2)
Hydrogen Ions (H+)
Electrons (e-)
Photosynthesis: Stage 2
The H+ and e- are pushed through the
electron transport chain to make NADPH
NADPH is like a rechargeable battery
Photosynthesis: Stage 3
This stage DOES NOT require LIGHT.
NADPH provides the energy to combine CO2
molecules into carbohydrates such as glucose
(C6H12O6)
This process is called the “Calvin Cycle”
3 Carbon Sugars
CO2
Carbohydrates
ADP
Calvin
Cycle
ATP
NADP +
NADPH
Photosynthesis: The Reaction
(6) CO2 + (6) H2O
Light
C6H12O6 + (6) O2
Enzymes
Reactants: Carbon Dioxide & Water
Products: Glucose & Oxygen
What’s Next?
Some glucose is
stored as starch.
The rest of it goes to
the cytoplasm to
begin to make ATP
through Cellular
Respiration!!