In 1939, Dr. R. Hill and R. Scarisbrick demonstrated that isolated chloroplasts
ID: 481058 • Letter: I
Question
In 1939, Dr. R. Hill and R. Scarisbrick demonstrated that isolated chloroplasts generate oxygen in the absence of carbon dioxide when light, water, and an artificial electron acceptor such as ferricyanide are available. Fericyanide was shown to be reduced to ferrocyanide in the illuminated chloroplast samples, but no NADPH or reduced plastocyanin (Pc) was formed. Choose the two statements that best explain why no NADPH or reduced Pc were formed. Ferricyanide blocks the oxidation of water. No reduced Pc was produced because ferricyanide acts as a "dead end"electron acceptor and thus disrupts the flow of electrons. Carbon dioxide was not available to accept electrons. No NADPH Was produced because ferricyanide is not an electron carrier. NADPH Was not produced because oxygen generation was disrupted in PS II.Explanation / Answer
1) No reduced Pc was produced because ferricynide acts as a dead end electron acceptor and this disrupts the flow of electrons.
2) Carbon dioxide was not present to accept electron.