Transcript
Photosynthesis
(Life from )
6H2O + 6CO2 ----> C6H12O6+ 6O2
Light
A little backgroundOrganisms
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
Ribose
P 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 whereThe bond breaksTo turn ATP intoADP
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 organic
molecules
• We will be looking at how autotrophs and how they synthesize these organic molecules through photosynthesis
CO2
Where does photosynthesis occur? In the chloroplasts!
absorbsunlight & CO2
makeenergy & 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
This is the equation you are used to seeing, but this is not the whole story…
+ water + energy glucose + oxygencarbondioxide
6CO2 6H2O C6H12O6 6O2light
energy+ ++
Photosynthesis• Actually two separate reactions
– Energy building• use sunlight• make energy (ATP)
– Sugar building• use ATP• use CO2
• make sugars (C6H12O6)
Energybuilding reactions
Sugarbuilding reactions
sun
ATPADP
CO2sugar
Energy Building Reactions
O2
H2O
Energy BuildingReactions
sunlight
ATP
H2O ATP O2light
energy ++
makes ATP energy releases oxygen
as a waste product
Sugar Building Reactions
sugarsC6H12O6
CO2
SugarBuilding
Reactions
ATP
CO2 C6H12O6 ADPATP ++
ADP
builds sugars uses ATP cycles ADP
back to make more ATP
Putting it all together
sugarsC6H12O6
CO2
ATP
ADP
H2O
O2
sunlight
CO2 H2O C6H12O6 O2light
energy + ++
SugarBuilding
Reactions
Energy Building
Reactions
Plants make both: ATP sugars
So what does a plant need?
• Takes in– CO2– H2O– light
• Releases– O2
• Produced and moved around– sugars
roots
shoot
leaves
How can a leaf do this? Let’s briefly examine the leaf structure
H2O CO2
CO2
O2 H2O
phloem (sugar)
xylem (water)
Stoma (pore/hole)
O2
Stomata • Function of stomata
– CO2 in
– O2 out
– H2O out
guard cell
Stomata (pore or hole)
Xylemcarry water up from roots
Phloem: food-conducting cells
carry sugars around the plant wherever they are needed new leavesfruitseeds
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?
glucose + oxygen carbon + water + energydioxide
C6H12O6 6O2 6CO2 6H2O ATP+ + +
Respiration
+ water + energy glucose + oxygencarbondioxide
6CO2 6H2O C6H12O6 6O2light
energy + ++
Photosynthesis
H2O
Energy cycle
Photosynthesis
Cellular Respiration
sun
The Great Circleof Life!
glucose O2CO2
plants
animals, plants
ATP
Resources
• www.bio.kimunity.com• Miller, Ken and Joe Levine. Prentice hall
Biology. Pearson Education Inc. New Jersey, 2005.
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