Question

The deficiencies of micro nutrients, not only affects growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect most, both photosynthetic and mitochondrial electron transport

• A. Cu, Mn, Fe
• B. Co, Ni, Mo
• C. Mn, Co, Ca
• D. Ca, K, Na

Answer 1

Answer: (A)

Cu, Mn, Fe

Iron is the qualitatively most important trace metal involved in thylakoid reactions of all oxygenic organisms since linear electron flow from H${}_2$O to NADP+ involves PS2, cytochrome b6-f, PS1 and ferridoxin. Manganese is second to iron in its quantitative role in the thylakoids, with 4 Mn per PS${}_2$ involved in O${}_2$ evolution. Plastocyanin is a copper-containing protein involved in electron-transfer. By this we can conclude that the deficiencies of micro nutrients,not only affects growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the other micro nutrients such as Co, Ni, Ca, K, Na etc, copper, manganese and iron mostly affects the photosynthetic and mitochondrial electron flow.
Therefore, the correct answer is option A.