Question

Electrons from excited chlorophyll molecule of Photosystem II are accepted first by?

• A. Quinone
• B. Cytochrome – f
• C. Cytochrome – b
• D. ferredoxin

Answer 1

The correct option is A

Quinone

The correct option is A

Explaination of the correct answer:

1. Quinone accepts electrons from the activated photosystem II chlorophyll molecule first.
2. A set of photosynthetic pigments and electron carriers called photosystem II are found in the appressed region of grana thylakoids.
3. Chlorophyll a, b, and carotenoids are all parts of the photosystem II. Phaeophytin, plastoquinone (PQ), cytochrome complex, and blue copper-containing plastocyanin are further PS II constituents.
4. Quinones are a class of organic compounds that, according to their formal definition, are "derived from aromatic compounds such as benzene or naphtha by converting an even number of -CH= groups into -C(=O)- groups with the required double bond rearrangement, resulting in “a complete conjugated cyclic dione structure.”
5. The archetypal member of the class is 1,4-benzoquinone or cyclohexadienedione, generally referred to as "quinone" (thus the name of the class). Other noteworthy examples include 1,2-benzoquinone (ortho-quinone), 1,4-naphthoquinone, and 9,10-anthraquinone.

The explanation for the incorrect options:

Option B:

1. The biggest constituent of the cytochrome complex is cytochrome f. It performs a role in the chain of electron transport
2. Cytochromes are redox-active proteins with heme as a cofactor that participates in the electron transport chain and redox catalysis. They also include a central Fe atom at their core. They are categorized based on the type of heme and how it binds.

Option C:

1. Eukaryotic cells contain the protein cytochrome b in their mitochondria. It performs a role in the chain of electron transport.
2. One of the 11 parts of a collection of proteins known as complex III is cytochrome b.
3. Adenosine triphosphate (ATP), the primary energy source for the cell, is produced by oxidative phosphorylation, a procedure carried out in the mitochondria by complex III.

Option D:

1. Small proteins called ferredoxins have iron and sulfur atoms arranged in iron-sulfur clusters. Any group of proteins with sulfur and iron that serve as electron carriers in some anaerobic bacteria, photosynthetic organisms, and nitrogen-fixing bacteria.
2. Ferredoxin transports electrons. Electrons are taken out of the water and transported to ferredoxin during photosynthesis.

Final Answer: Quinone accepts electrons from the activated photosystem II chlorophyll molecule first.