Respiration in Plants Question 52

52. Terminal cytochrome of respiratory chain

which donates electrons to oxygen is [1992]

(a) Cyt. b

(c) Cyt. $a_1$

(b) Cyt. $c$

(d) Cyt. $a_3$

Show Answer

Answer : d

Hints & Solutions

(d) Terminal cytochorome is cyt $a_3$. It posseses two copper centres. It helps in transfer of electrons to oxygen.

2 CuA molecules functions in allowing the electrons to enter the enzyme from cytochrome c. Heme $ _{a}$ functions in allowing the electrons to be transferred from CuA to the second heme, hemea3. The iron in heme $ _{a 3}$ functions in binding oxygen, with the help of $CuB$.