Ivan_Lujan_Block5_MM5
Conversion of light energy to chemical energy of food
Chloroplasts
Structure
Chlorophyll
Stroma
Thylakoids
Green pigment in plants
Envelope of two membranes
Stacks of interconnected membranes
Function
Help convert light energy to energy for plants
Sight of photosynthesis
Photosynthetic equation
6CO2 + 6H2O + light energy = C6H12O6 + 6O2.
Reactants
Products
Carbon dioxide, water, and light energy
glucose and water
Splitting of water
Oxygen is derived from water
Spit by chloroplasts
Splits water
Redox process
Electron flow is reverse from Cellular respiartion
Two Stages of Photosynthesis
Gain potential energy as it is a catabolic reaction
Light reactions
Calvin cycle
Convert solar energy to chemical energy
Reduces fixed carbon to carbohydrate
Absorbed by chlorophyll
NADP+ fucntions as an electron carrier
Reduced to NADPH by electrons and Hydrogen
Generate ATP
Reducing power given by NADPH
Requires ATP
Light Reactions in depth
Sunlight
Belongs to visible light spectrum
Transmits particles known as photons
contain fixed energy
Light receptors
Different pigments absorb different lights
Spectrophotometer
The ability of a pigment to absorb various wavelengths
absorption spectrum show light absorption from pigments
Excitation of Chlorophyll by light
Electrons move to a higher state when absorption of photons occur
Energy lost as heat
Photosystem
A reaction center surrounded by a number of light harvesting complexes
Each consists of a pigment molecules bound to particular proteins
Reaction center
Protein complex that includes two special chlorophyll a molecules and a molecule called the primary electron accpetor
Photosystem 1 and 2
Found in Thylakoid membranes
Noncylic electron flow
Light energizes the two photosystems to drive the synthesis of NADPH and ATP
Two possible routes for electron flow
Noncylic
Cyclic
Prodominate route
Photon strikes
Electron picked by primary
enzyme splits water molecule
Forms O2
Exergonic fall of electrons provides energy for ATP
Photoexcited electrons from chain then carried by NADP+ to form NADPH
use only Photosystem 1
Short circut
Only generates ATP
Underwent when high levels of NADPH
The Calvin Cycle in depth
Anabolic process
Carbon enters in form of CO2
each attaches to a five carbon sugar named ribose
Forms six carbon intermediate unstable
Splits to two molecules of 3-phophoglycerate
Each molecule receives a phosphate from ATP
NADPH reduces it to G3P
Stores potential energy
Carbon skeletons are rearranged into three molecules of RuBP
via ATP
G3P then used as a starting block fro glucose