Transcript 6CO 2

Photosynthesis:
Life from Light and Air
Energy needs of life
 All life needs a constant input of energy

Animals = Heterotrophs
 get their energy from “eating others”
 eat food = other organisms = organic molecules
 make energy through respiration

Plants = Autotrophs
 get their energy from “self”
 get their energy from sunlight
 build organic molecules (food) from CO2
 make energy through photosynthesis
Photosynthesis: the process that uses the sun’s
energy to make simple sugars, such as glucose.
6CO2 + 6H2O → C6H12O6 + 6O2
Carbon Dioxide + Water → Glucose + Oxygen
How do plants live?
 Photosynthesis

Energy building reactions
 collect sun energy
 make ATP

Sugar building reactions
 use ATP for energy
 use CO2 as carbon for new sugars
 build sugars
 glucose, cellulose, starch
 build all other organic molecules
 proteins, lipids, carbohydrates, DNA
 store energy for future use
 starch in seeds & roots
Photosynthesis
 Actually 2 separate reactions

Energy building
Energy
building
reactions
 use sunlight
 make energy (ATP)

sun
Sugar building
 use ATP
ATP
ADP
Sugar
building
reactions
 use CO2
 make sugars (C6H12O6)
CO2
sugar
Chloroplasts
CO2
 absorb


sunlight & CO2
make
energy & sugar
Contain chlorophyll
Light-Dependent Reactions
H2O +
light  ATP + O
2
energy
H2O
 makes ATP energy
 releases oxygen
sunlight
as a waste product
Energy Building
Reactions
ATP
O2
Light-Independent Reactions
CO2 + ATP  C6H12O6 + ADP
CO2
ADP
 builds sugars
 uses ATP
 cycles ADP back to
Sugar make
Building
Reactions
ATP
sugars
C6H12O6
more ATP
Putting it all together
CO2 + H2O + light  C6H12O6 +
energy
H2O
CO2
sunlight
ADP
Plants make both:
 ATP
 sugars
Sugar
Building
Reactions
Energy
Building
Reactions
ATP
O2
O2
sugars
C6H12O6
So what does a plant
need?
 Bring In
leaves
CO2
 H2O
 light

 Let Out

O2
 Move Around

shoot
roots
sugars
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy