Photosynthesis. PS Learning Targets 1-8. Photosynthesis Outline. LT’s 1-3: Energy and Old Dead Dudes LT’s 4 & 5: Light and Structures of PS LT’s 6-8: Reactions and Factors of PS . ENERGY. LT 1. All living things need energy to live!
PS Learning Targets 1-8
LT’s 1-3: Energy and Old Dead Dudes
LT’s 4 & 5: Light and Structures of PS
LT’s 6-8: Reactions and Factors of PS
All living things need energy to live!
(Ex: herbivores, carnivore, decomposers, etc)
(Ex: plants, bacteria, and some protists)
What are the uses for ATP in biochemical reactions?
? If plants use visible light, are all colors/wavelengths/energies equally valuable to PS?
Read the results of the experiment from Thomas Engelmann in 1803
ROY BIV is absorbed andG is reflected.
Pigment – any substance that absorbs light
Chlorophyll a – the main pigment in plants
that absorbs the sun’s light to power PS
chlorophyll b and carotenoids
Chlorophyll a best absorption occurs around 425nm AND 660nm
Chlorophyll b best absorption occurs around 475nm AND 640nm
Carotenoids best absorption occurs around 450nm AND 490nm
Therefore, the accessory pigments expand the absorption from about 425nm (V) to 425-490nm (V-B) AND from 660nm (R) to 640-660nm (O-R). More light absorbed = More PSing!!
So how do they know to change color??
But what about the anthocyanins?
So for good fall leaf color…
Now…The Leaf and Chloroplasts
Palisdade Layer-layer of long cells where chloroplastsare found and where most of PS occurs
Spongy Mesophyll-random collection of cells with large spaces in between them. Some PS occurs here, but mostly this is where the gases taken in & given off by PS are exchanged between palisade layer and stoma
Guard Cells-the cells on either side of the stoma that open/close them to let gases in or out OR to keep gases in
Stoma- openings on the underside of leaves that allow for gas exchange between the leaf and atmosphere.
Let’s see this
1 of 2 membranes that surround the organelle
Fluid between the thylakoidswhere the dark rxn occurs
Disc where the pigments of PS are. Where the light rxn occurs
6 & 7How Photosynthesis Occurs
? So what about the rest of the PS equation; like CO2, Water, Glucose and O2 ?
6CO2+ 6H2Olight C6H12O6 + 6O2
PS occurs in 2 parts
“I’m So Excited!”
electron carriers receive
chlorophyll’s electrons the excited e-’s and pass get very excited from the them along to other sun’s energy molecules. These e-’s carriers molecules are
ELECTRON TRANSPORT CHAIN
Examples of a Carrier Molecule:
NADP+ + 2e- + 1H+NADPH
PS II - In the Thylakoid Membrane (TM)
H+’s , e-’s , and O2
PS I - In the Thylakoid Membrane (TM)
Let’s See This
A Little Quiz:
8Limiting Factors to PS
There are factors that limit the amount of PS
Light Energy from the sun
High energy sugars