Light Emission Flashcards
Electromagnetic radiation is:
The oscillations between electric and magnetic components of light that correspond to different wavelengths of the electromagnetic spectrum.
Wavelength is ——— proportional to frequency is ——— proportional to energy
inversely; directly
Absorption and emission of light by molecules is due to
Electronic transitions in the orbitals, changes in electronic configuration.
Equation for calculation of light energy
ΔE = hc/λ
Jablonksi diagram of fluorescence
Displays different vibrational states that exist within each of the excited and ground state groups.
Transitions within these groups is non-radiative, energy lost is only in the form of heat.
Fluorescent molecules emit light at a ______ wavelength than is absorbed
Longer (lower energy)
Changes in fluorophore colour
Due to energy difference between the ground/excited states
Fluorescent amino acids
Intrinsic - tryptophan, tyrosine, phenylalanine
Green fluorescent protein structure
Try, Thr, Gly with self catalysed maturation to induce more conjugation between bonds.
Occurs with folding, nucleophilic attack (intramolecular), enolisation to stabilise, then oxidation.
Green fluorescent protein mechanism
Absorption of blue light forms an excited anion, but emission of green light (higher wavelength)
Changes in stability of excited state effect on wavelength released
Greater wavelength, because there is less energy in the excitation
GFP derivatives
created through mutagenesis by changing amino acids to either change conjugation or stabilise the excited state
GFP as a research tool
Attaching to or encoding in proteins allows for the visualisation and tracking of these, such as actin involved in Pickmann C disease. Monitor where the protein is in the cell.
Fluorescence guided surgery
Fluorophores linked to folate are more likely to be taken up by cancer cells, allowing for the visualising cancer tissues alone. Increases the success rate of surgical oncology.
