Your cells contain two types of nucleic acids, ribonucleic acid and deoxyribonucleic acid, or RNA and DNA, respectively. They differ from the other macronutrients in that they are not a source of calories in your diet, and their role is strictly to direct the synthesis of new protein molecules.
The definition of a postgraduate is a student who is studying a subject beyond the college level when he already has a college degree. Someone attending medical school is an example of a postgraduate.
The Master of Philosophy (abbr. M.Phil. or MPhil, sometimes Ph.M.; Latin Magister Philosophiae or Philosophiae Magister) is a postgraduate degree. In most cases, it is an advanced research degree with the prerequisites required for a Master of Philosophy degree making it the most advanced research degree before the Doctor of Philosophy (Ph.D. or D.Phil.).