| Class 12 Biology Marks Distribution |
| Units | Marks |
| Reproduction | 14 |
| Genetics and Evolution | 18 |
| Biology and Human Welfare | 14 |
| Biotechnology and its Applications | 12 |
| Ecology and Environment | 12 |
| Total | 70 |
CBSE Class 12 Biology Syllabus
- Reproduction in Organisms
- Sexual Reproduction in Flowering Plants
- Human Reproduction
- Reproductive Health
- Principles of Inheritance and Variation
- Molecular Basis of Inheritance
- Evolution
- Human Health and Diseases
- Strategies for Enhancement in Food Production
- Microbes in Human Welfare
- Biotechnology - Principles and Processes
- Biotechnology and its Application
- Organisms and Populations
- Ecosystem
- Biodiversity and its Conservation
- Environmental Issues
Course Syllabus Details
Unit VI. Reproduction
Chapter 1: Reproduction in Organisms
- Reproduction
- A characteristic feature of all organisms for continuation of species
- Modes of Reproduction −
- Asexual reproduction
- Sexual reproduction
- Asexual reproduction −
- Modes-Binary fission
- Sporulation
- Budding
- Gemmule
- Fragmentation
- vegetative propagation in plants
Chapter 2: Sexual Reproduction in Flowering Plants
- Flower structure
- Development of male and female gametophytes
- Pollination −
- Outbreeding devices
- Pollen-Pistil interaction
- Double fertilization
- Post fertilization Events-Development of endosperm and embryo
- Development of seed and formation of fruit
- Special modes −
- Apomixes
- Parthenocarpy
- Polyembryony
- Significance of seed and fruit formation
Chapter 3: Human Reproduction
- Male and female reproductive systems
- Microscopic anatomy of testis and ovary
- Gametogenesis −
- Menstrual cycle
- Fertilisation embryo development up to blastocyst formation, implantation pregnancy and placenta formation (Elementary idea)
- Parturition (Elementary idea)
- Lactation (Elementary idea)
Chapter 4: Reproductive Health
- Need for reproductive health and prevention of sexually transmitted diseases (STD)
- Birth control −
- Need and Methods
- Contraception
- Medical Termination of Pregnancy (MTP)
- Amniocentesis
- Infertility and assisted reproductive technologies −
- IVF
- ZIFT
- GIFT (Elementary idea for general awareness)
Unit VII. Genetics and Evolution
Chapter 5: Principles of Inheritance and Variation
- Mendelian Inheritance
- Deviations from Mendelism −
- Incomplete dominance
- Co-dominance
- Multiple alleles
- Inheritance of blood groups
- Pleiotropy
- Elementary idea of polygenic inheritance
- Chromosome theory of inheritance
- Chromosomes and genes
- Sex determination in −
- Linkage and crossing over
- Sex linked inheritance −
- Haemophilia
- Colour blindness
- Mendelian disorder in humans
- Chromosomal disorders in humans −
- Down's syndrome
- Turner's
- Klinefelter's syndromes
Chapter 6: Molecular Basis of Inheritance
- Search for genetic material and DNA as genetic material
- Structure of DNA and RNA
- DNA packaging
- DNA replication
- Central dogma
- Transcription, genetic code, translation
- Gene expression and regulation −
- Genome and human ganeome project
- DNA fingerprinting
Chapter 7: Evolution
- Origin of life
- Biological evolution and evidences for biological evolution (Paleontological, comparative anatomy, embryology and molecular evidence)
- Darwin's contribution
- Modern Synthetic theory of Evolution
- Mechanism of evolution −
- Variation (Mutation and Recombination)
- Natural Selection with examples
- Types of natural selection
- Gene flow and genetic drift
- Hardy - Weinberg's principle
- Adaptive Radiation
- Human evolution
Unit VIII. Biology and Human Welfare
Chapter 8: Human Health and Diseases
- Pathogens - parasites causing human diseases −
- Malaria
- Filariasis
- Ascariasis
- Typhoid
- Pneumonia
- Common cold
- Amoebiasis
- Ring worm
- Basic concepts of immunology – Vaccines −
- Adolescence, drug and alcohol abuse
Chapter 9: Strategies for Enhancement in Food Production
- Improvement in food production −
- Plant breeding
- Tissue culture
- Single cell protein
- Biofortification
- Apiculature
- Animal husbandry
Chapter-10: Microbes in Human Welfare
- In household food processing
- Industrial production
- Sewage treatment
- Energy generation and as biocontrol agents
- Biofertilizers
- Antibiotics −
- Production and judicious use
Unit IX. Biotechnology and Its Applications
Chapter 11: Biotechnology - Principles and Processes
- Genetic engineering (Recombinant DNA technology).
Chapter 12: Biotechnology and its Application
- 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
Unit X. Ecology and Environment
Chapter 13: Organisms and Populations
- Organisms and environment −
- Habitat
- Niche
- Population
- Ecological adaptations
- Population interactions −
- Mutualism
- Competition
- Predation
- Parasitism
- Population attributes −
- Growth
- Birth rate
- Death rate
- Age distribution
Chapter 14: Ecosystem
- Patterns
- Components
- Productivity
- Decomposition
- Energy flow
- Pyramids of number, biomass, energy
- Nutrient cycles (carbon and phosphorous)
- Ecological succession
- Ecological services −
- Carbon fixation
- Pollination
- Seed dispersal
- Oxygen release (in brief)
Chapter-15: Biodiversity and its Conservation
- Concept of biodiversity
- Patterns of biodiversity
- Importance of biodiversity
- Loss of biodiversity
- Biodiversity conservation −
- Hotspots
- Endangered organisms
- Extinction
- Red data book
- Biosphere reserves
- National parks
- Sanctuaries
- Ramsar sites
Chapter-16: Environmental Issues
- Air pollution and its control
- Water pollution and its control
- Agrochemicals and their effects
- Solid waste management
- Radioactive waste management
- Greenhouse effect and climate change
- Ozone layer depletion
- Deforestation
- Any one case study as success story addressing environmental issue(s).
Practical Works
Part A: List of Experiments
- Study pollen germination on a slide.
- 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.
- Collect water from two different water bodies around you and study them for pH, clarity and presence of any living organisms.
- Study the presence of suspended particulate matter in air at two widely different sites.
- Study of plant population density by quadrat method.
- Study of plant population frequency by quadrat method.
- Prepare a temporary mount of onion root tip to study mitosis.
- Study the effect of different temperatures and three different pH on the activity of salivary amylase on starch.
- Isolation of DNA from available plant material such as spinach, green pea seeds, papaya, etc.
Part B: Study/observation of the following (Spotting)
- Flowers adapted to pollination by different agencies (wind, insect, bird).
- Pollen germination on stigma through a permanent slide.
- Identification of stages of gamete development, i.e., T.S. of testis and T.S. of ovary through permanent slides (from grasshopper/mice).
- Meiosis in onion bud cell or grasshopper testis through permanent slides.
- T.S. of blastula through permanent slides.
- Mendelian inheritance using seeds of different colour/sizes of any plant.
- 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.
- Controlled pollination - emasculation, tagging and bagging.
- Common disease causing organisms like Ascaris, Entamoeba, Plasmodium, Roundworm through permanent slides or specimens. Comment on symptoms of disease that they cause.
- Two plants and two animals (models/virtual images) found in xeric conditions. Comment upon their morphological adaptations.
- Two plants and two animals (models/virtual images) found in aquatic conditions. Comment upon their morphological adaptations.
Structure of CBSE Biology Sample Paper for Class 12 Science is
| Type of Question | Marks per Question | Total No. of Questions | Total Marks |
| Very Short Answer Type Questions | 1 | 5 | 5 |
| Short Answer Type Questions - 1 | 2 | 7 | 14 |
| Short Answer Type Questions - 2 | 3 | 12 | 36 |
| Long Answer Type Questions | 3 | 5 | 15 |
| Total | 27 | 70 |
For Preparation of exams students can also check out other resource material
CBSE Class 12 Biology Sample Papers
CBSE Class 12 Biology Worksheets
CBSE Class 12 Biology Question Papers
CBSE Class 12 Biology Test Papers
CBSE Class 12 Biology Revision Notes
Importance of Question Bank for Exam Preparation?
There are many ways to ascertain whether a student has understood the important points and topics of a particular chapter and is he or she well prepared for exams and tests of that particular chapter. Apart from reference books and notes, Question Banks are very effective study materials for exam preparation. When a student tries to attempt and solve all the important questions of any particular subject , it becomes very easy to gauge how much well the topics have been understood and what kind of questions are asked in exams related to that chapter.. Some of the other advantaging factors of Question Banks are as follows
- Since Important questions included in question bank are collections of questions that were asked in previous exams and tests thus when a student tries to attempt them they get a complete idea about what type of questions are usually asked and whether they have learned the topics well enough. This gives them an edge to prepare well for the exam.Students get the clear idea whether the questions framed from any particular chapter are mostly either short or long answer type questions or multiple choice based and also marks weightage of any particular chapter in final exams.
- CBSE Question Banks are great tools to help in analysis for Exams. As it has a collection of important questions that were asked previously in exams thereby it covers every question from most of the important topics. Thus solving questions from the question bank helps students in analysing their preparation levels for the exam. However the practice should be done in a way that first the set of questions on any particular chapter are solved and then solutions should be consulted to get an analysis of their strong and weak points. This ensures that they are more clear about what to answer and what can be avoided on the day of the exam.
- Solving a lot of different types of important questions gives students a clear idea of what are the main important topics of any particular chapter that needs to focussed on from examination perspective and should be emphasised on for revision before attempting the final paper. So attempting most frequently asked questions and important questions helps students to prepare well for almost everything in that subject.
- Although students cover up all the chapters included in the course syllabus by the end of the session, sometimes revision becomes a time consuming and difficult process. Thus, practicing important questions from Question Bank allows students to check the preparation status of each and every small topic in a chapter. Doing that ensures quick and easy insight into all the important questions and topics in each and every individual. Solving the important questions also acts as the revision process.