3. What is
Photosynthesis
• Photosynthesis is the trapping
(fixation) of carbon dioxide and its
subsequent reduction to carbohydrate
using hydrogen from water.
• Light energy to is converted to
chemical potential energy
This Photo by Unknown Author is licensed under CC
6. Knowing the
Pigments
• Rf value: distance travelled
by pigment spot divided by
distance travelled by the
solvent
• Result will depend on the
solvent used.
7. Knowing the Pigments
•Rf value of carotenoids close to 1
•Rf value of chlorophyll b lowest value
•Rf value chlorophyll a value between carotenoids and chlorophyll b
8. The
Photosystem
s
• Photosystem I – main
wavelength of light
absorbed is 700 nm
• Photosystem II - main
wavelength of light
absorbed is 680 nm
15. Harvesting Light
Energy
• When a photon strikes a pigment molecule in
a light-harvesting complex, the energy is
passed from molecule to molecule until it
reaches the reaction-center complex.
• Here, an excited electron from the special pair
of chlorophyll a molecules is transferred to the
primary electron acceptor.
21. Light Independent
Reaction
The end product of photosysnthesis isn’t really
glucose; it’s TP (Triose Phosphate) . It can be used to
manufacture glucose, or other sugars, fatty acids or
amino acids.
Photophosporylation @ thylakoid membrane🡪 ATP & NADPH
(released in stroma)
Calvin cycle completely happens @ stroma.
It is sometime called dark reaction because it does not need light
energy to happen but not necessarily only happens at night
24. Light
Intensity
• Further than the limiting
value, light is not a
limiting factor anymore.
• It may be the
temperature or carbon
dioxide concentration
This Photo by Unknown Author is licensed under CC
25. Temperature
• In light dependent reaction,
temperature have no
significant effect.
• Only in Calvin cycle that
temperature play major role,
as this is a common
enzyme-controlled reaction.
• Interpret the graph!
26. Carbon
Dioxide
• In light dependent reaction,
carbon dioxide had no
significant effect.
• Only in Calvin cycle that
carbon dioxide play major
role, as it is the substrate of
Rubisco.
• Interpret the graph!
28. C4 and CAM Plants
• Points to remember:
• Plants always try to reduce transpiration
• During daylight, light dependent reaction
happens in maximum rate.
• Plants can conduct Calvin cycle during
daylight.
