BSEB 12th Biology Weightage 2026 - Check chapter wise weightage

The Bihar School Examination Board (BSEB) Class 12 Biology examination 2026 will be conducted shortly. Students must be aware of the exam pattern and weightage to prepare well and score well in the exam. Biology is one of the important papers for PCMB students, so here is a detailed breakdown of the biology paper weightage in the BSEB 12th exam 2026. The exam is conducted for 3 hours and 15 minutes. The total marks for Biology are 100, 70 marks for the theory paper and 30 marks for the practical exam. Students must score atleast 33% in both the papers (theory and practical paper) to pass in the subject.

The theory paper is divided into multiple sections, including objective and subjective questions. In the objective section, students will get multiple-choice and short-answer questions. In the subjective portion, there will be long-answer type questions. Alongside this, the practical exam marks will be based on experiments, spotting, viva-voce, and record/project work.

Biology’s curriculum is divided into five major units, and students must focus primarily on important units like Genetics & Organic Evolution, Biotechnology & Its Applications, and Applied Biology & Human Welfare. These units carry the highest weightage. There will be a total of 96 questions in the theory paper, divided into two sections. 

Section A contains 70 questions worth 1 mark each, of which students must answer any 35. Section B includes 20 short-answer questions, each worth 2 marks, and students must answer 10. Additionally, there are 6 long-answer questions in this section, of which students must answer 3; each carries 5 marks.

Here is a detailed breakdown of the BSEB class 12th biology weightage to help students have a clear idea of the syllabus and tips to score well using this weightage.

BSEB 12th Biology Exam Pattern 2026

The Bihar School Examination Board (BSEB) Class 12 Biology exam is conducted for 100 marks, 70 marks theory exam, and 3 marks practical exam. The theory paper will be conducted for 3 hour 15 minutes, and students must score atleast 33% marks in each paper to pass the subject. 

The theory question paper is divided into two sections, namely:

• Section A consists of 70 multiple-choice questions (MCQs), each worth 1 mark. Students need to answer any 35 of these.
   
• Section B includes 20 short-answer type questions, each of 2 marks. From these, students must attempt 10 questions. It also contains 6 long-answer type questions, each carrying 5 marks, and students are required to answer any 3 out of 6.

So, there will be 96 questions in total, and students need to answer 48 out of these. The practical/internal exam is of 30 marks and is based on laboratory experiments, observations, interpretation of experimental results, and viva-voce. 

Also Read: BSEB 12th Biology Exam Pattern 2026

BSEB 12th Biology Unit-Wise Weightage 2026

Students can check below the detailed unit-wise breakdown of marks for the BSEB Class 12 Biology exam 2026. The breakdown is for 70 marks of the theory paper: 

As it’s clear from the above weightage breakdown that units like Genetics & Organic Evolution, Biotechnology & Its Applications, and Applied Biology & Human Welfare are the highest-weightage units, each carrying 18 marks. So, students must focus mainly on these units to score well on the paper. Reproduction & Development carries 6 marks, while Ecology & Environment contributes 10 marks to the theory paper. So, these need less attention than units II, III, and IV.

Also Read: Bihar Board 12th Biology Syllabus 2026

BSEB 12th Biology Chapter-Wise Weightage 2026

Once you’re clear with the unit-wise marks distribution, you must also know the most important topics covered in these units. Below is a detailed breakdown of the marks distribution among the important topics of the BSEB 12th biology. This will help you to focus on the most important chapters more.

BSEB 12th Biology Weightage 2026: Practical Examination Marks Breakdown

Candidates can check the detailed breakdown of the 70 marks practical examination:

Also Read: BSEB 12th Biology Deleted Syllabus 2026

BSEB 12th Biology 2026: Typology of Questions and Marks Allotted

The BSEB 12th Biology theory paper is of 70 marks, and the question paper is a combination of MCQs, short answer type questions, and long answer type questions. Out of 96 questions, students must answer 48 questions.

Also Read: Bihar Board 12th Previous Year Question Papers

How to Score High Using BSEB 12th Biology Weightage 2026

Candidates can use the BSEB class 12th weightage mentioned above to score well in the exam in the following ways:

• Students must first be thorough with the chapter-wise and unit-wise marks distribution and weightage.
• You must focus on high-weightage units like genetics and evolution, biotechnology and its application, applied biology and human welfare. Each unit carries 18 marks.
• Make detailed notes on these units and also short notes, which will be helpful during the last-minute revision.
• Students must not forget to practise diagrams, as they are important for the biology paper.
• You must collect past year papers and sample papers, and practise them regularly. This will help you to remain confident on the exam day.
• As a practical paper consists of 30 marks, students must be prepared with their records and perform well in the practical examination.
• Students must prepare a schedule and practice at least 1.5 hour daily to perform well in the exam, and start with the high-weightage units always.

The above-mentioned BSEB 12th biology weightage will help students to make a customised study plan. Students must focus on high-weightage units like genetics and evolution, biotechnology and its application, applied biology and human welfare. You must complete your practical records on time and perform well in the practical examination, including the experiment, observation and viva-voce exam.