Question

Respiration and photosynthesis both require?
(a) Green cells
(b) Sunlight
(c) Cytochromes
(d) Organic fuel

Answer 1

Hint: Both respiration and photosynthesis synthesise ATP therefore both require the transfer of electrons with the help of those substances that help in the synthesis of ATP. Green cells like chloroplast and sunlight help in photosynthesis.

Complete answer:
In the case of respiration, cytochromes act as respiratory complexes. It acts as a heme protein and the action of cytochrome was mostly seen during terminal oxidation.
The whole process of photosynthesis requires two photosynthetic reaction complex centres like photosystem II and photosystem I. It starts with Photosystem II and ends with Photosystem I. The transfer of electrons between both the photosystems take place with the help of cytochrome like b6f complex.

Additional Information:
In terminal oxidation of aerobic respiration, the passage of electrons and protons both take place which helps in the reduction of coenzyme to oxygen. In the electron transport chain of terminal oxidation, the inner mitochondrial membrane consists of some protein and enzymes. These enzymes and cytochrome pass electrons from substances to an acceptor. The electron carriers of the electron transport chain consist of flavins, iron-sulphur complexes, quinones and cytochrome. An electron from NADH in mitochondrial matrix get oxidise by NADH dehydrogenase and this electron then transfers to ubiquinone in the inner membrane and production of ${FADH_2}$ take place during oxidation of succinate through succinate dehydrogenase. The reduced ubiquinone then oxidised with the transfer of an electron to cytochrome C via cytochrome bC complex. Complex four has cytochrome c which oxidises complexes containing cytochrome a and copper centres and in the last complex production of ATP take place from ADP and inorganic phosphate.

So, the correct answer is Cytochrome.

Note:
In the case of electron transport, the higher electron affinity present in the electron acceptor as compared to the electron donor. The electron transport takes place from the inner matrix of mitochondria to the outer side in the proton gradient.