Vitamin K

From Biology-Online Dictionary | Biology-Online Dictionary



A fat-soluble vitamin found mainly in leafy green vegetables, with a chemical formula C 31 H 46 O 2, and is essential for the normal blood clotting


Vitamins are essential for the normal biological functions. Inadequate amount of vitamins in the body may result in disorders or diseases. Humans need different types of vitamins and vitamin K is one of them. Similar to other vitamins such as vitamin A, vitamin D, and vitamin E, vitamin K is fat-soluble. That means it is capable of incorporating into biological membranes. Vitamin K differs from other fat-soluble vitamins in being largely associated with blood clotting particularly by helping the body produce the appropriate amounts of prothrombin. This is why vitamin K is also referred to as antihemorrhagic factor. Therefore, deficiency of vitamin K may result in impaired blood coagulation or uncontrolled bleeding. Apart from this function, vitamin K is also essential in modifying certain proteins to make them bind to calcium ions in bones and other tissues. Consequently, an inadequacy of vitamin K in the diet results in weak bones. Vitamin K is found largely in green leafy vegetables, as well as in egg yolks and liver.


  • phylloquinone
  • phytomenadione
  • phytonadione
  • antihemorrhagic factor

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