CBSE 12- Must Know Biology Topics

Dear students,

Biology is a subject of life and life forms, so try to build genuine interest in it. Here are a few tips on how to master this subject:

**FREE Biology Board Paper Solutions

• Release your fear for the subject.
• Set your time in accordance with the topic.
• Follow the board pattern and weightage of marks allotted to each unit.
• Here is the unit-wise weightage of marks allotted by CBSE in Biology.

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• According to the weightage pattern, the Unit-Genetics and Evolution holds the highest marks.

• Here are some tips to make genetics a cake walk. Practice the crosses related to Mendelian genetics thoroughly.

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– One can make short flow charts or tables in order to remember these crosses.
– Given below is a table representing the genotypic and phenotypic ratios of the crosses involved in Mendelian genetics.

Study the processes related to molecular biology (such as DNA replication, transcription and translation) very well. Prepare pointers for these processes.

• Split the technical terms, etymologically for better understanding. For Example: in order to remember the term karyokinesis, split it into karyo (meaning nucleus) and kinesis (meaning synthesis).

– These pointers work for the rest of the units as well. Try to make mind maps and flow charts for the processes involved in biotechnology.

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– Clear any doubt related to any topic immediately from your mentor, teacher, tutor or friend. Else,post your doubts on ‘Ask and Answer’ on meritnation.com and get expert help. Remember “Expert help is just a click away”.

How to Revise
– Develop the habit of revising point-wise.
– At the time of revision, do not go for any new topic as it may confuse you.
– Practice the diagrams as they are the most important aspect of biology.

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– Practice sample papers prescribed by CBSE to get a fair idea of what to expect in the exam.
– Go through the previous years’ board papers especially those of the recent five years because some questions are being repeatedly asked.

For example: The question on the structure of antibody has been asked in 2009, 2010 and 2011 in the papers of the Delhi region. The way in which the question was asked was different but the answer is almost similar.

The questions were:

(i) What does the above diagram illustrate?
(ii) Name the parts labelled ‘a’ and ‘b’.
(iii) Name the type of cells that produce this molecule. 2010 (Set 3) – 3 marks
An antibody molecule is represented as H2L2. Explain. 2010 (Set 3) – 3 marks

Identify A, D, E and F in the diagram of an antibody molecule given below.

From analysis of the board papers of the past 3 years, it is apparent that the long answer questions seem to come from the unit 1, 2, 4 and 5. So, try to concentrate on these units for the long answer questions.

During the Examination
– Go through the entire paper and mark the questions you are confident about before starting to answer.
– Write the correct question numbers for the answers.
– Avoid leaving any answer blank. Try to write the closest answer you remember.
– Do not leave sheets blank in between your answers.
– Give diagrams and tables wherever necessary. While doing diagrams, keep in mind that, a well-labelled diagram fetches more marks compared to a colourful one. Here is the diagram drawn by a topper of 2011 which fetched full marks.

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It is a popular misconception that the long-answer questions need to have lengthy answer No, try to keep the answers to the point and brief.
Try to list down the important points for the long-answer questions and then elaborate on them. For example: For a question on PCR, first list down the steps involved such as Denaturation, Annealing and Elongation and then explain these steps.

All the best!
Team Meritnation