<prompt> Cysteine is synthesized fromMethionineArginineHistidineLysine  <response>: Methionine is first conveed to active methionine and then it is conveed to cysteine on combining with serine.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 217, Fig 16.14, 16.15. 