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Chapter 8: Photosynthesis, Leen Badawi, 202103371 - Coggle Diagram
Chapter 8: Photosynthesis
The energy within light is captured and used to synthesise carbohydrates ( energy from light drives this endergonic reaction)
Energy cycle; cells that use organic molecules for energy and plants replenish those molecules using photosynthesis
Trophic levels
2- Autotroph
3- Photoautotroph
1- Heterotroph
CHLOROPLASTS
organelles in plants and algae that carries out photosynthesis
green pigment is CHLOROPHYLL
majority of photosynthesis occurs in leaves in the mesophyll
has three membrane ( outer, inner, and thylakoid membranes)
Granum is the stacks of the thylakoid
Stroma ; between thylakoid membranes and inner membrane
reactions that harness light energy
travels as waves ( short to long waves)
behave as particles called photons ( shorter wavelengths have more energy)
light is a type of electromagnetic radiation
two stages of photosynthesis
1- Light reactions
2- Photosystem ll
it’s the initial step in a photosynthesis
Excited electrons travel from PSII to PSI
Oxidize water to generate O2 and H+
Happen in thylakoid
Produce
2- NADPH
3- O2
1- ATP
1- Photosystem l
it primary role to make NADPH
Addition of H+ to NADP+ contributes to H+
2- Calvin cycle
have three phases
1- Carbon fixation
2- reduction and carbohydrates production
3- the regeneration of RuBP
use ATP and NADPH to incorporate CO2 into carbohydrates
happen in the stroma
Variations in photosynthesis
Environmental conditions can influence both efficiency and the way the Calvin cycle works
2- Temperature
3- Water availability
1- Light intensity
C3 Plants
it use less energy to fix the CO2
it happen in 90% or more of plants
happens in cooler weather
C4 Plants
happen in worm dry conditions
it conserves water and prevent photo respiration
leaves have two-cell layers
1- Mesophyll cells
2- Bundle-sheath cells
CAM Plants
it open during the night
it use CO2 to converted them to malata
happens in the stomata
stomata close durning the day to conserve water
The electrons flow
1- Noncyclic
electrons begins at the PSII and eventually transfers to NADPH in a linear process
Produce both ATP and NADPH in an equal amounts
2- Cyclic
it produces ATP only
PSI electrons are excited and then release energy and eventually they return to PSI
electron cycling release energy to transport H+ into lumen driving the ATP synthesis
Leen Badawi, 202103371