CBSE Class 12th Biology Weightage 2026 - Check chapter wise weightage

Jan 16, 2026 | CBSE 12th

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Each chapters and topics in CBSE Class 12th Biology exam has different weightage. Knowing about the weightage helps students prioritise topics accordingly. Check here CBSE Class 12th Biology Weightage 2026!

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The CBSE Class 12th Biology Weightage 2026 covers the unit-wise, chapter-wise marks distribution along with the marks distribution in internal assessment. Before you appear for the CBSE Class 12th Exam 2026, you are advised to check the weightage of every subject carefully. The theory exam is conducted for 70 marks, and the internal assessment is 30 marks. The CBSE Class 12th Biology Syllabus is divided into five units, which are further divided into various chapters.

If you check the CBSE Class 12th Biology Weightage 2026 carefully, you will find that, unit "Genetics and Evolution" has high weightage in the exam among all other units. Then the unit " Reproduction" comes, and after that the rest units. Checking the weightage does not mean you have to study the high-weightage units only. This means that you have to focus more on units that have high weightage and revise them multiple times, and also have to study the low weightage chapters. In case you have less time, then you can only study the high-weightage topics.

Read the entire article to know what is the unit-wise and chapter-wise weightage of CBSE Class 12th Biology.

CBSE Class 12th Biology Exam Pattern 2026

You should know the CBSE Class 12th Biology Weightage 2026 along with the CBSE Class 12th Biology Exam Pattern 2026. The exam pattern will help you in understanding what the exam paper looks like. In the CBSE Class 12th Biology exam 2026, there will be five sections and a total of 33 questions. The total marks for which the exam will be conducted are 70. The exam will consist of objective, description, and case-based questions, which encourage you to focus more on concepts rather than rote learning. A detailed breakdown is provided below for the CBSE Class 12th Exam Pattern 2026.

Sections	Types of Question	Number of Questions	Total Marks
A	Multiple Choice Questions or Assertion-reason-based questions	16	16 (One mark each question)
B	Short Answer Question	5	12 (Two marks each question)
C	Short Answer Question	7	21 (Three marks each question)
D	Case-based questions	2	8 (Four marks each question)
E	Long Answer Question	3	15 (Five marks each question)
Total		33 questions	70

CBSE Class 12th Biology Unit-Wise Weightage 2026

There are five units in CBSE Class 12th Biology. The two units "Biology and Human Welfare" and "Biotechnology and its application" consist of 12 marks each. The remaining units have different weightage. The highest weightage is of the unit "Genetics and Evolution". The following table summarises the CBSE Class 12th Biology Weightage 2026 as per the units.

Units	Marks Weightage
Reproduction	16
Genetics and Evolution	20
Biology and Human Welfare	12
Biotechnology and its application	12
Ecology and Environment	12
Total	70 marks

Also Read: CBSE Class 12th Biology Syllabus 2026

CBSE Class 12th Biology Chapter-Wise Weightage 2026

There are a total of 13 chapters that cover the entire units of the CBSE Class 12th Biology. Knowing the chapter-wise weightage is also important. You get to know which chapter carries how much weightage. In CBSE Class 12th Biology Weightage 2026, chapter one under the unit "Reproduction" carries more weightage. The chapter that carries the most weightage among others is "Human Health and Diseases," which carries 9 marks. You can see the CBSE Class 12th Biology Chapter-Wise Weightage 2026 in detail from the table below.

Units	Chapters	Marks Weightage
Reproduction	Chapter 1: Sexual Reproduction in Flowering	7
	Chapter 2: Human Reproduction	6
	Chapter 3: Reproductive Health	3
Genetics and Evolution	Chapter 4: Principles of Inheritance and Variation	8
	Chapter 5: Molecular Basis of Inheritance	8
	Chapter 6: Evolution	4
Biology and Human Welfare	Chapter 7: Human Health and Diseases	9
Biology and Human Welfare	Chapter 8: Microbes in Human Welfare	3
Biotechnology and its application	Chapter 9: Biotechnology- Principles and Processes	6
Biotechnology and its application	Chapter 12: Biotechnology and Its Applications	6
Ecology and Environment	Chapter 11: Organisms and Populations	5
	Chapter 12: Ecosystem	3
	Chapter 13: Biodiversity and Conservation	2
Total		70 marks

Also Read: CBSE Class 12th Biology Preparation

CBSE Class 12th Biology Internal Assessment Weightage 2026

The CBSE Class 12th Biology Weightage 2026 says that the CBSE Class 12th Internal Assessments are of 30 marks overall. These marks are distributed among various components. You can check which component is allotted how many marks from the table shown below.

Components	Marks Allotted
Finding out the apparatus name	05
A written test	12
Practical Records	05
Viva	12
Total	30

Also Read: CBSE Class 12th Biology Previous Year Question Papers 2026

Tips to Score High Using CBSE Class 12th Biology Weightage 2026

The points mentioned below will help you know the tips that can help you immensely to use the CBSE Class 10 Biology Weightage 2026 for scoring high marks.

Firstly, get the PDF of CBSE Class 12th Biology Weightage 2026. Refer to it when you are studying any unit or chapter.
When you are studying a unit, check the CBSE Class 12th Biology Weightage 2026 to know in that unit, which chapter carries high weightage. The chapter that carries high weightage is important, and you have to focus more on that.
When you are revising the Biology subject, also, check the CBSE Class 12th Biology Weightage 2026 once, so that you can once again make yourself aware of the high-weightage topics.
Along with high-weightage chapters, you have to focus on low-weightage chapters also. These chapters will also help you score good marks.