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.
This term, then, encompasses freshmen through senior college students. A graduate degree is anyone that occurs beyond the undergraduate degrees, such as Master's and Ph.D. programs as well as some of the others discussed below. These students are often called grad students, short for graduate students. slide 2 of 3.