To be used for energy or information light must be absorbed
Lecture 2 Light
1. Relationship between excited states of a pigment and its absorption, fluorescence
2. Region of the electromagnetic spectrum known as “visible light”.
3. Relationship between wavelength and energy content of a photon.
Shorter the wavelength, stronger energy the wave has (inversely related)
The amount of energy in the blue photon is higher than the amount of energy in
the red photon.
4. Molecular characteristic of visible pigments that make them able to absorb light.
This conjugated (ring) system (the alternation of double bonds and single bonds)
represents or indicates the specific kind of electron configuration; these are
non-bonding electrons (Pi orbital electrons). Those electrons will interact with the
photons of light. They are not required for bonding.
5. Relationship between pigments and associated protein.
Pigments are bound non-covalently to the proteins.
When you isolated protein carefully enough, you can keep the pigments attached:
6. Four “fates” of the excited state of chlorophyll resulting from absorption of photons.
Lose energy as heat
Lose a little energy as heat, and then lose the energy as fluorescence
Do work (photochemistry)
Energy transfer 7. Reason(s) why relative fluorescence is different in isolated chlorophyll vs. intact cells
when exposed to light.
Intact cell: the energy that is absorbed from exciting the electrons is used to power
photosynthesis (and other essential processes in the cellDue to presence of protein
complex and reaction centre in the intact cells, the energy re