At a glance
- Subject code
- 044
- Theory
- 70 marks, 3 hours
- Practical
- 30 marks
- Largest unit
- Genetics and Evolution, 20 marks
- Question mix
- 50% knowledge, 30% application, 20% analysis
Theory marks by unit, Class 12 (2026-27)
| Unit | Chapters | Marks |
|---|---|---|
| VI Reproduction | Sexual reproduction in flowering plants; human reproduction; reproductive health | 16 |
| VII Genetics and Evolution | Principles of inheritance and variation; molecular basis of inheritance; evolution | 20 |
| VIII Biology and Human Welfare | Human health and diseases; microbes in human welfare | 12 |
| IX Biotechnology | Principles and processes; applications in health and agriculture | 12 |
| X Ecology and Environment | Organisms and populations; ecosystem; biodiversity and its conservation | 10 |
| Total | 70 |
Environmental issues (pollution, global warming, ozone depletion) are in the CBSE reading material and assessed only formatively in 2026-27. Source: CBSE Biology curriculum 2026-27.
The 30-mark practical exam
| Component | Marks |
|---|---|
| One major experiment | 5 |
| One minor experiment | 4 |
| Slide preparation | 5 |
| Spotting | 7 |
| Practical record and viva | 4 |
| Investigatory project with record and viva | 5 |
| Total | 30 |
Where Class 12 Biology marks are lost
- Genetics crosses: setting out a dihybrid cross or a sex-linked cross (haemophilia, colour blindness) without clear parental genotypes, gametes and ratios.
- Molecular basis of inheritance: the lac operon and the steps of transcription and translation described in the wrong order.
- Diagrams: the anther, embryo sac, ovary section and the structure of a replication fork asked for with labels, and drawn without them.
- Biotechnology: muddling restriction enzymes, vectors and selectable markers when explaining recombinant DNA.
- Ecology: describing population interactions with the wrong sign (+, -, 0) for each species.
- Case-based questions on human health, where students recognise the disease but not the pathogen or the mode of transmission.
How one-to-one Class 12 Biology lessons work
Lessons are 60 minutes, one to one, in LiveTutor's online classroom with video and a shared whiteboard. Biology looks like memorisation, but the board paper rewards explanation: the tutor asks your child to explain a process aloud, then turns that explanation into a written answer of the right length for 2, 3 or 5 marks. Genetics problems are worked step by step on the board until the layout becomes a habit.
A tutor who teaches CBSE Biology keeps closely to NCERT, since its wording and diagrams are the basis of most questions, and uses the CBSE sample paper and marking scheme to show which keywords earn marks.
When to start
Reproduction opens the year, but genetics is where most students need help, so starting before Principles of Inheritance is ideal. If your child is also preparing for medical entrance exams, mention it when you book so we can match a tutor who teaches at that depth. One lesson a week usually keeps pace with school; two help in the final months before the boards.
Common questions
Which Biology unit carries the most marks?
Genetics and Evolution, with 20 of the 70 theory marks in 2026-27. It covers inheritance and variation, the molecular basis of inheritance and evolution.
Is the environmental issues chapter in the board exam?
Not in 2026-27. CBSE has moved environmental issues into reading material that is assessed only in school.
How is the Biology practical marked?
A major experiment (5), a minor experiment (4), slide preparation (5), spotting (7), the practical record and viva (4), and the investigatory project with its record and viva (5).
How important are diagrams?
Very. Many questions ask for labelled diagrams, and marks go to correct labels as well as the drawing. The tutor practises the NCERT diagrams until your child can draw them quickly from memory.
How much does Class 12 Biology tutoring cost?
$15 a lesson, the same for every subject and level, on a weekly plan of 1 to 5 lessons billed monthly. The first lesson is a free trial.
Sources
Dates and figures on this page come from these official and published sources. Always confirm deadlines on the official page before acting on them.