Question

Which of the following acts as an electron carrier in both photosynthesis and respiration
A)${ F }_{ 1 }$ region
B)Phytochrome
C)Cytochrome
D)Cryptochrome

Answer 1

Hint: It is composed of a heme known as redox-active proteins present with a central Fe atom at the core which acts as a cofactor. It performs the electron transport chain and redox catalysis and classifies according to the type of heme and its mode of binding.

Complete answer:
-A group of hemoprotein cell components that undergo reduction and oxidation of electrons with the presence of enzymes known as cytochrome. It helps in the transfer of energy within the cells. These are the proteins that are connected to a non-protein iron-bearing component.
-It plays a vital function in electron transport which is associated with the membranes of the thylakoids in the process of photosynthesis. Electrons from the photosystem II are accepted by it through plastoquinone and across the membrane it contributes to proton transport.
-In the electron transport chain, there are four membrane-bound proteins complexes (complex I–IV) and through them, the electron passes with the help of electron carriers namely ubiquinone (Q), cytochromes, and iron-sulfur proteins.
-The electron transport associated with aerobic cellular respiration, cytochrome-c plays a very important role in it. It is a small heme protein that belongs to the inner membrane of the mitochondria.
-It transfers electrons between complex III and complex IV in the electron transport process.

Additional Information: Phytochromes - It is used to detect the light belonging to the class of photoreceptors in plants, bacteria, and fungi. In the red and far-red region of the visible spectrum, they are generally sensitive to light and can be classed as either that are activated by far-red light known as type I or that is activated by a red light known as Type II
Cryptochromes - They are sensitive to blue lights belonging to the class of flavoproteins. They are found in plants and animals. It is involved in the circadian rhythm of plants and animals and in a number of species helps in the sensing of magnetic fields.
${ F }_{ 1 }$ region - The region i.e ${ F }_{ 1 }$ of ATP synthase is generally hydrophilic which is responsible for hydrolyzing ATP. Into the mitochondrial matrix space, the ${ F }_{ 1 }$ unit protrudes. Also, make a hexamer with 6 binding sites with Subunits $\alpha $ and $\beta $

So, the correct answer is,” cytochrome”.

Note: -In both the photosynthesis and respiration processes cytochrome acts as an electron carrier. That's why they are capable of performing both oxidation and reduction.
-Within the membranes, the cytochromes as well as other complexes held in an organized way. Therefore the redox reactions carried in the proper sequence for maximum efficiency.