Success Lies in the DNA

What are the important questions in Biology?

Question 1: Explain the process of DNA transcription?

DNA Transcription is one of the most important and tricky topics in the Class 12 biology board examination. Most likely, there will be a question on the mechanism process of DNA transcription. While answering such a question, a student often gets confused and makes mistakes in naming of the strand ( coding and non-coding). He could forget to replace thymine with uracil in messenger RNA. Often, students get confused in the upstream and downstream directions of the DNA Strand.

Students have to keep in mind the following while answering a question on DNA transcription:

i)Polarity of DNA strand

ii) In RNA thymine is replaced by Uracil

iii) The strand of DNA which serves as template for formation of mRNA is called non-coding strand and the other stand is called coding stand.

Apart from the above question, in any other question relating to DNA transcription, the student should keep the above points in mind.

Question 2: In the below diagram given, answer the following questions:
I.What does the diagrammatic sketch depict?
II.Identify ‘a’ ‘b’?
III.Name the widely used diagnostic test when a person gets this disease?


A very crucial part of the biology examinations are the diagram-based questions. Such questions are either taken from chapters on ecology or from lifecycle of diseases. While preparing for the exam, students often neglect diagrams in NCERT books and then lose marks as they are not able to attempt such questions.

In this diagram, the students get confused and often don’t know the stages shown in the life cycle.

The student should first identify the diagram and the infectious stages shown. While answering the question, the student needs to give the description of the diagram. The above diagram depicts the life cycle of AIDS virus, how it infects and how it multiplies inside the host.

Published in Hindustan Times, New Delhi, January 28, 2015

(The set of questions and answers have been compiled by subject experts of biology department at Studymate.)