Confusion to Conclusion

Class 12th cbse board exams are very crucial as they impact the further studies of a student. Hence, to choose a stream of one’s own choice, every student wants to perform best and score well in the exams. 

For students, who want to pursue their career in the medical field, biology is the most crucial subject. Class 12th biology is a theoretical subject, therefore students can score good marks in it if prepared with a proper strategy. In this blog, we have discussed the CBSE class 12th biology exam pattern so that students can understand the weightage of units, pattern of question paper etc which can help them in scoring good marks in the paper.

Class 12th Biology Unit Wise Marking

Following is given the unit wise marks distribution of CBSE class 12th biology:

Unit No. Unit Marks
6 Reproduction 14
7 Genetics and Evolution 18
8 Biology and Human Welfare 14
9 Biotechnology and its Applications 12
10 Ecology and Environment 12
Total 70


Class 12th Biology Question Paper Pattern

Class 12th biology paper consists of 70 marks with 33 questions. The paper is divided into four sections: Section A, Section B, Section C and Section D. The time duration is 3 hours 15 minutes. There will be no overall choice. However, internal choices will be provided in some questions.

Section No. Of Questions Marks
A 14 1 mark each
2 Case based questions
B 9 2 marks each
C 5 3 marks each
D 3 5 marks each


CBSE Class 12th Biology Assessment Areas (Theory Paper)

Demonstrate Knowledge and Understanding 50%
Application of Knowledge / Concepts 30%
Analyse, Evaluate and Create 20%


CBSE Class 12th Biology Practical Marks

Class 12th biology has 30 practical marks. The practical marks distribution is given below:

Evaluation Scheme Marks
One Major Experiment 5
One Minor Experiment 4
Slide Preparation 5
Spotting 7
Practical Record + Viva Voce 4
Investigatory Project & its

Project Record + Viva Voce

Total 30


List of Experiments

  1. Prepare a temporary mount to observe pollen germination.
  2. Collect and study soil from at least two different sites and study them for texture, moisture content, pH and water holding capacity. Correlate with the kinds of plants found in them.
  3. Collect water from two different water bodies around you and study them for pH, clarity and presence of any living organism.
  4. Prepare a temporary mount of onion root tip to study mitosis.
  5. Study the effect of different temperatures or three different pH on the activity of salivary amylase on starch.
  6. Isolate DNA from available plant material such as spinach, green pea seeds, papaya, etc.

Study/observation of the following (Spotting)

  1. Flowers adapted to pollination by different agencies (wind, insects, birds).
  2. Identification of stages of gamete development, i.e., T.S. of testis and T.S. of ovary through

permanent slides (from grasshoppers/mice).

  1. Meiosis in onion bud cell or grasshopper testis through permanent slides.
  2. T.S. of blastula through permanent slides (Mammalian).
  3. Prepared pedigree charts of any one of the genetic traits such as rolling of tongue, blood groups, ear lobes, widow’s peak and colour blindness.
  4. Common disease causing organisms like Ascaris, Entamoeba, Plasmodium, any fungus causing ringworm through permanent slides, models or virtual images. Comment on symptoms of diseases that they cause.
  5. Two plants and two animals (models/virtual images) found in xeric conditions. Comment upon their morphological adaptations.
  6. Two plants and two animals (models/virtual images) found in aquatic conditions. Comment upon their morphological adaptations.

Biology Reference Books for Class 12

Following are some best biology reference books for class 12:

  • NCERT Class 12 Biology Textbook
  • CBSE Biology Chapterwise Solved Papers class 12th
  • Pradeep’s A Text Book of Biology class 12


Students have got various doubts and confusion in mind before the exam. GrabGuidance provides academic guidance for students of class 8th to 12th, graduation and post graduation. If you are facing any difficulties in or have any queries or doubts in class 12th biology, you can book a session with any of the GrabGuidance biology experts and get all your doubts and concepts cleared. There are 20 mins, 40 mins, 60 mins or even multiple sessions available. You can book any of them according to your convenience.

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