iconimg Tuesday, August 04, 2015

Savita Sharma, Hindustan Times
New Delhi, February 26, 2013
Biology is a theoretical subject. While writing the answer, it’s very important to be specific rather than play around with words. Here are three examples to explain what to do and not in answering the questions
Explain the process of DNA transcription? DNA transcription is one of the most important and tricky topics for Class 12 biology board examination. Most probably there will be a question about the mechanism of DNA transcription.

In such questions the students get confused and make mistakes in naming of the DNA strand (coding and non-coding). They forget to replace thymine with uracil in mRNA and most of the students are absolutely clueless about the upstream and downstream directions of the template DNA strand.

The student has to keep in mind the following points while answering any question on DNA transcription:
i) Polarity of DNA strand. Promoter is located in the upstream direction of the coding DNA strand
ii) In RNA thymine is replaced by uracil.
iii) The DNA strand which serves as the template for formation of mRNA is called the non-coding strand and the other is called coding strand.

Answer the following: I. What does the diagrammatic sketch depict?
II. Identify ‘a’ and ‘b’?
III. Name the widely used diagnostic test when a person gets this disease?

A very crucial part of the biology examinations is the diagram-based questions. Such questions are either asked from ecology (especially population graphs) or life cycle of diseases. While preparing for the exam, students often neglect various diagrams in NCERT and then lose their marks as they are not able to attempt such questions.

In the case of the given diagram, students often don’t know the stages shown in the life cycle.

The student should first identify the diagram and the infectious stage shown in it. While answering the question, s/he needs to give the description of the diagram.

Explain the hormonal control of the male reproductive system or the female reproductive system?

Students often attempt the question on hormonal control of the reproductive system in a wrong manner. They need to be very specific at the time of answering the question and not go into unnecessary detail. They mostly start explaining the process of gametogenesis whereas the question is asking about various hormones and their role in the reproductive system; how they cause production and maturation of gametes. Ideally the answer should first have a flow chart diagram followed by names and role of each hormone specifying the stage at which it is released or acts.

(The author is head, department of biology, HT Studymate)


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