Transcript Photosynthesis PP

Photosynthesis
(Life from
)
Light
6H2O + 6CO2 ----> C6H12O6+ 6O2
A little background
Organisms
autotrophs
heterotrophs
Make own food
Obtain food from others
• Grass  Caterpillar  Bird
• Autotroph Heterotroph  Heterotroph
• All energy originates with Autotrophs
The fuel of living things
• ATP- Adenosine triphosphate
– Consists of
• Adenine
• 5-carbon sugar called ribose
• Three phosphate groups
– Key to ATP’s ability to release energy
Adenine
P
Ribose
P
P
ADP
• ADP is a cousin of ATP
– Main differences
• ADP has 2 phosphates ATP has
3
• ADP has less energy then ATP
This is where
The bond breaks
To turn ATP into
ADP
ADP
The photosynthesis equation
• The process by which light energy is converted into
chemical energy and stored in organic compounds
• Referred to as biochemical pathway
6H2O + 6CO2  energy C6H12O6 + 6O2
Reactants
Products
Energy needs of Life
• All life needs a constant input of energy
– Heterotrophs (animals, fungi, most bacteria)
• get their energy from “eating others”
• consumers of other organisms
• consume organic molecules
– Autotrophs (plants, some bacteria)
• get their energy from “self”
• use sunlight energy to synthesize
molecules
organic
• We will be looking at how
autotrophs and how they
synthesize these organic
molecules through
photosynthesis
Where does photosynthesis occur? In the
chloroplasts!
absorb
CO2 sunlight & CO2
make
energy & sugar
Light: absorption spectrum
• Light reaction can perform work with wavelengths of
light that are absorbed
– chlorophyll a — the dominant pigment — absorbs best in
red & blue wavelengths & least in green
– other pigments with different structures have different
absorption spectra
Chloroplasts
• Green because absorb
light wavelengths in
red & blue and reflect
green back out
THAT IS WHY PLANTS LOOK GREEN TO US! WE SEE WHAT IS RELFECTED.
Photosynthesis:
Overall Equation
carbon + water + energy  glucose + oxygen
dioxide
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy
This is the equation you are used to seeing,
but this is not the whole story…
Photosynthesis
• Actually two separate reactions
– Energy building
Energy
building
reactions
• use sunlight
• make energy (ATP)
– Sugar building
sun
ATP
ADP
• use ATP
• use CO2
• make sugars (C6H12O6)
Sugar
building
reactions
CO2
sugar
Energy Building Reactions
H2O +
H2O
 makes ATP energy
 releases oxygen
as a waste product
sunlight
Energy Building
Reactions
ATP
O2
light  ATP + O
2
energy
Sugar Building Reactions
CO2 + ATP  C6H12O6 + ADP
CO2
ADP
Sugar
Building
Reactions
ATP
sugars
C6H12O6
 builds sugars
 uses ATP
 cycles ADP
back to make
more ATP
Putting it all together
CO2 + H2O + light  C6H12O6 +
energy
H2O
CO2
sunlight
ADP
Sugar
Building
Reactions
Energy
Building
Reactions
ATP
O2
sugars
C6H12O6
O2
Plants make both:
 ATP
 sugars
So what does a plant
need?
• Takes in
– CO2
– H2O
– light
leaves
• Releases
shoot
– O2
• Produced and moved
around
– sugars
roots
How can a leaf do this?
xylem (water)
Let’s briefly examine the leaf structure
phloem (sugar)
O2 H O
2
CO2
Stoma
(pore/hole)
O2
H 2O
CO2
Stomata
• Function of stomata
– CO2 in
– O2 out
– H2O out
guard cell
Stomata
(pore or
hole)
Xylem
carry water up from roots
Phloem: food-conducting cells
 carry sugars around the
plant wherever they are
needed
 new leaves
 fruit
 seeds
Putting it all together
• Making a living…
– sunlight
• leaves = solar collectors
• photosynthesis
– gases: CO2 in & O2 out
• stomata = gases in & out
– H2O
• roots take in water from soil
• pulled up by leaf evaporation
– nutrients
• roots take in from soil
How are cellular respiration and
photosynthesis connected?
Respiration
glucose + oxygen  carbon + water + energy
dioxide
C6H12O6 +
6O2
 6CO2 + 6H2O + ATP
Photosynthesis
carbon + water + energy  glucose + oxygen
dioxide
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy
Energy cycle
sun
Photosynthesis
plants
CO2
glucose
H2O
animals, plants
Cellular Respiration
The Great Circle
of Life!
ATP
O2
Resources
• www.bio.kimunity.com
• Miller, Ken and Joe Levine. Prentice hall
Biology. Pearson Education Inc. New Jersey,
2005.