text: Along with chlorophyll and three iron-sulfur proteins, a form of this compound serves as an early electron acceptor in photosystem
full_question: Along with chlorophyll and three iron-sulfur proteins, a form of this compound serves as an early electron acceptor in photosystem I, and is known as phylloquinone. In animals, this compound serves as a cofactor for reactions that gamma-carboxylate glutamate receptors into Gla receptors. The epoxide form of this vitamin is reduced by an enzyme targeted by the drug (*) Warfarin. This vitamin, which is abundant in green leafy vegetables, is needed to activate factors II, VII, IX, and X, and along with vitamins A, D, and E, it is fat- soluble. Hematomas and bruising can result from a deficiency of this vitamin, which is symptomatically similar to hemophilia. For 10 points, name this vitamin important for blood clotting.
first_sentence: Along with chlorophyll and three iron-sulfur proteins, a form of this compound serves as an early electron acceptor in photosystem
raw_answer: Vitamin K [or phylloquinone before mentioned; or menaquinones]