Scoring more in biology

Board exams are the litmus test for students of Class-XII. Biology is not only important for board exams but also for AIPMT and other competitive examinations. The entire board exams of biology comprises of two tests —Theory (70 marks) + Practical (30 marks).

Divide your time judiciously for each topic according to the weightage. Divide the entire syllabus of board exam into three parts — easy, medium and difficult.

CBSE Question Paper for Biology consist of 30 questions in which there are Very Short Answer Questions (1 marks each), Short Answer Questions (2 and 3 marks) and Long Answer Questions (5 marks each). These questions are distributed in four sections — A, B, C and D, respectively.

Reproduction, Biology in Human Welfare and Ecology comprise 42 marks. So these topics should be completed first. The questions framed in these topics are from recall and recognition domain of knowledge. So learning is an essential part for attempting them. A proper and frequent revision of these topics is very important.

Genetics and Biotechnology need to be understood before learning, as the questions framed are conceptual. If the concepts are not understood properly, then answering would be difficult.

• Answer to each question should be in points. Avoid paragraph writing and repetition.
• Answer to 1 mark question should be of one word or one sentence only. Such as

Question: What is Hardy-Weinberg's equation for genetic equilibrium? (1 mark)

Answer: p2 + 2pq + q2 = 1

• Answer to 2 or 3 marks question should be of two or three lines. Such as

Question: What do you mean by eutrophication? Write any two consequences of this phenomenon? (2 marks)

Answer: It is defined as natural ageing of lakes by nutrient enrichment of its water. (1 mark)

Consequences :

a) It causes algal bloom. (½ mark)

b) Causes death of aquatic organism due to O2 depletion. (½ mark)

• Answer to 5 marks question should be of 10-15 lines. If it is a diagram based topic, draw well labelled and neat diagram.
• Diagram is not only meant for 5 marks question, it can be drawn wherever required.
• Instead of writing lengthy answer write short specific points and illustrate them with line diagram if possible.
• In reproduction important definitions, examples and diagrams are to be learned and practiced thoroughly. Diagrams should be properly labeled.
• In Genetics Mendelian crosses are to be learnt by practicing them and making proper tables and flow charts. This will help in learning ratio and pattern of inheritance.
• In Evolution topics should not be mixed for example Hardy-Weinberg equilibrium and Human evolution are two separate topics. So, distinguishing feature of each topic is to be remembered.
• Biology in Human Welfare chapters are entirely based on memory and therefore should be properly memorized. For example: Himgiri is a hill bunt and rust resistant variety of wheat.
• Biotechnology is an application-based chapter. For example, preparation of genetically engineered insulin, PCR, gel electrophoresis etc. should be understood properly.
• Ecology has fact-based chapters, which requires complete observation of surrounding and you should be vigilant about environmental issues like ozone hole, green house effect, Kyoto protocol etc.

— With inputs from Aakash Chaudhry, Director, Aakash Educational Services