Question

Choose the correct answer from the alternatives given.
When an electron has been excited to a higher energy state, it can then drop back to the original level, re-emitting the light as fluorescence. When chlorophyll is extracted in solution, and a bright red or blue light is shown on it, the chlorophyll fluoresces brightly. However, when the chlorophyll is packaged inside chloroplasts and the red or blue light is turned on, there is no fluorescence. This most likely indicates that

• A. the red and blue light waves are reflected by the chlorophyll membrane
• B. Chlorophyll in solution is a different molecule than chlorophyll in a chloroplast
• C. excited electrons are transferred to electron acceptors in the chloroplast
• D. green light must be used to make living cells fluoresce

Answer 1

The correct option is C excited electrons are transferred to electron acceptors in the chloroplast

The photo-systems present in the chloroplast of the plant has a light-harvesting complex and a core complex. Each core complex contains a reaction centre with the pigment (either P₇₀₀ or P₆₈₀) that can be photochemically oxidized, together with electron acceptors and electron donors. These are arranged in a manner of increasing reduction potential (tendency to accept electrons). This ensures the flow of electrons and hence there is no chance of fluorescence.

So, the correct option is, 'excited electrons are transferred to electron acceptors in the chloroplast'.