ICSE Class 12 Biology Marking Scheme

Marking Scheme for Biology

Class 12th is a final year of the schooling education, and it becomes very essential to have a good percentage to get into any well-known University or college. Class 12th result reflects your overall performance and effort you put in all the twelve years. Formation of base of your career starts from Class 12th and it’s very important to score an impressive percentage.

When we compare two boards like ICSE and CBSE, we have some similarities and some slight differences. CBSE is recognized by the Indian government and ICSE is not. Although the certificates provided by both of them are globally valid. CBSE Board approves both English and Hindi language as the medium of instructions; ICSE does not recommend Hindi.

When it comes to Class 12 Biology, it involves Diagrammatic representation for every answer and mostly detailed explanation. Therefore, it’s important to know the marks allocation of each and every unit and prepare accordingly. Here are the units of CBSE Class 12 Biology and marks allocation of every unit.






14 marks


Genetics and evolution

18 marks


Biology and Human Welfare

14 marks


Biotechnology and its applications

10 marks


Ecology and environment

14 marks

1) Reproduction

The first unit of Class 12th Biology consists of Reproduction, a characteristic feature of all organisms for the continuation of species; Asexual reproduction. Modes of reproduction-Asexual and sexual reproduction; Modes-Binary fission, sporulation, budding, gemmule and fragmentation; vegetative propagation in plants.

2) Genetics and evolution

The maximum marks are carried by the second unit it consists of topics like Mendelian Inheritance; Deviations from Mendelism-Incomplete dominance, Co-dominance, Multiple alleles and Inheritance of blood groups, Pleiotropy; Elementary idea of polygenic inheritance; Chromosome theory of inheritance; Chromosomes and genes; Sex determination – in humans, birds, honey bee; Linkage and crossing over; Sex linked inheritance – Haemophilia, Colour blindness.

3) Biology and Human Welfare

The third unit consists of aspects like Human health and diseases;Pathogens; parasites causing human diseases (Malaria, Filariasis, Ascariasis, Typhoid, Pneumonia, common cold, amoebiasis, ringworm); Basic concepts of immunology – vaccines; Cancer, HIV and AIDs; Adolescence, drug and alcohol abuse.

4) Biotechnology and its applications

Application of Biotechnology in health and agriculture: Human insulin and vaccine production, gene therapy; Genetically modified organisms-Bt crops; Transgenic Animals; biosafety issues, biopiracy and patents.

5) Ecology and environment

The fifth and the last topic consist of Organisms and Environment: Habitat and niche, Population and ecological adaptations; Population interactions-mutualism, competition, predation, parasitism; Population attributes growth, birth rate and death rate, age distribution.

These were the topics included in ICSE Class 12 Biology Marking Scheme according to the marks distribution and weightage. This provides you a better idea of how to prepare for the examination and where to give more stress. Apart from theoretical aspect, make sure your diagrams are neatly represented and correctly mentioned since they also carry marks along with your explanation. When it comes to procedures or steps, try to explain insteps; it gives a more clear picture. At last, make sure that you are thorough with all the concepts and try to solve at least last five years previous question papers by which you’ll get to know which question has been asked how many times. For more information Visit us at BYJU’S site

Practise This Question

Animal excreta and organic waste from kitchen can be profitably used for production of