The CBSE Class 12 biology exam is just two days away (March 15) and for students going over their notes for the last time, here are some important things to remember.

On writing the paper, Manisha Pande, a teacher at the Government Model Senior Secondary School, Sector 26, says, “I suggest they begin with the five- mark questions. It’s a part of the bulkier section of the paper so it should be tackled first when the students are not tired.”

Once that’s done the one- to three-mark questions can be solved in reverse order. “That has two benefits, most of the concept-based questions which many students find difficult carry three to five marks. If students deal with them first, being fresh of mind, they stand a good chance to get better marks.”

One-mark questions can be attempted quickly towards the end, when about 45 to 30 minutes are left. It will help students utilise the three hours effectively, says Vinod Chauhan, a biology tutor based in the city.

Ramanjit Kaur, biology teacher in Government Model Senior Secondary School, Sector 21, says, “There are five units in the biology examination. Unit one, on reproduction, carries around 14 marks so students cannot afford to leave out any topics. However, it is not so difficult. Revising the male and female reproductive system and practising diagrams of flowering plants can be taken into consideration.”

Unit two is conceptual and forms the most difficult section of the exam. Based on genetics and evolution it has 18 marks. Students must go through test crosses, Mendel’s principles and the laws of genetics. In evolution students must go through Darwin’s theory of evolution along with the evidence of evolution, Kaur advises.

Unit three is biology and human welfare, which also carries 14 marks. The chapter is based on experiments. There are many experiments to prove certain statements, so students have to know everything about it, she says.

Unit 4, biotechnology, is also concept-based and a somewhat “difficult” for students to understand. However, this section carries 10 marks. If they have gone through the unit earlier and understood it they won’t have any problems. One should just have clarity of concept,” she adds.

Unit 5 is ecology and environment, which is easy and has about 14 marks. However, don’t be overconfident. Remember, this section can mean that difference between high and low scores. “I will ask students to read it once properly before the exam. This is an easy section and chapters such as conservation and biodiversity are scoring ,” says Kaur

Neat and well-labelled diagrams add to scores, advises Chauhan. “Practice drawing diagrams. Students are also given diagrams in the exam and asked to label them. The important ones are sexual reproduction in flowering plants, molecular basis of inheritance, human reproduction, ecosystem, biotechnology - principles and processes, biotechnology and its applications.”

First Published: Mar 13, 2019 08:04 IST