Day 2

Question 1

Photosynthesis

Answer 1

Electrons from excited chlorophylls are passed to series of acceptors that convert electronic enegry to chemical energy

Question 2

Internal Converson

Answer 2

Mode of decay in which electronic energy is converted to kinetic energy. Chlorophyll usually relax to their lowest excited states; excitation energy of chlorophyll that has absorbed a photon in short-wavelength band is not different that if it had absorbed the photon in its less energetic long-wavelength band.

Question 3

Fluorescence

Answer 3

Electronically excited molecule decays to ground state by emitting a photon. Accounts for only 3-6% of light energy absorbed by living plants.

Question 4

Exciton Transfer (resonance energy transfer)

Answer 4

Excited molecule directly transfers its excitation energy to nearby unexcited molecules with similar electronic properites. Light energy is funneled to RC through exciton transfer amung antenna pigments and is trapped in RC chlorophylls because they have slightly lower excited state energies than antenna chorophylls.

Question 5

Photooxidation

Answer 5

Light-excited donor molecule is oxidized by transferring an electron to an acceptor molecule, which is thereby reduced. Excited chlorophyll is an electron donor energy of absorbed photon is chemically thrasfered to photosynthetic reaction system

Question 6

Electron Transport in Photosynthetic Bacteria

Answer 6

Bacteriochlorophyll undergoes photooxidation when hit with red light. Excited electron is transferred along series of carriers until it returns to the original bacteriochlorophyll. During electron transfer cytophlasmic protons are translocated across the plasma membrna eand this proton gradient is used to drive ATP synthesis. Hydrophobic domains coordinate pigments.

Question 7

Special Pair

Answer 7

two bacteriochlorophyll molecules closely associated. Bacteriochlorophyll is labeled based on absorbance maximums. P870 P960. Absorption of a photon by the special pair excited electron is delocalized over both bacteriochlorophyll molecules. Excited electron is passed to tother prosthetic groups present eventually making it back to the special pair via electron transport chain