| 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 board exams students can also check out other resource material
CBSE Class 12 Biology Sample Papers
Important Questions for Class 12 Biology Chapter Wise
CBSE Class 12 Biology Test Papers
Biology Revision Notes for class 12
Previous Year Question Paper CBSE Class 12 Biology
Why do one Children need Worksheets for Practice ?
It is very old saying that one can build a large building if the foundation is strong and sturdy. This holds true for studies also. Worksheets are essential and help students in the in-depth understanding of fundamental concepts. Practicing solving a lot of worksheets, solving numerous types of questions on each topic holds the key for success. Once basic concepts and fundamentals have been learnt, the next thing is to learn their applications by practicing problems. Practicing the problems helps us immensely to gauge how well we have understood the concepts.
There are times when students just run through any particular topic with casual awareness there by missing out on a few imperative “between the lines” concepts. Such things are the major causes of weak fundamental understandings of students. So in such cases Worksheets act as a boon and critical helpful tool which gauges the in-depth understanding of children highlighting doubts and misconceptions, if any.
Worksheets classifies the important aspects of any topic or chapter taught in the class in a very easy manner and increases the awareness amongst students.When students try to solve a worksheet they get to understand what are the key important factors which needs the main focus.Sometimes it happens that due to shortage of time all the major points of any particular topic gets skipped in the class or teacher rushes through , due to shortage of time. A worksheet thus provides a framework for the entire chapter and can help covering those important aspects which were rushed in the class and ensure that students record and understand all key items.
In a class of its say 40 students howsoever teacher tries to be active and work towards making each student understand whatever she has to teach in the class but there are always some students who tend to be in their own world and they wander in their thoughts.Worksheets which are provided timely to all the students, causes them to focus on the material at hand. it’s simply the difference between passive and active learning. Worksheets of this type can be used to introduce new material, particularly material with many new definitions and terms.
Worksheets help students be focussed and attentive in the class because they know after the class is over they will be assigned a worksheet which they need to solve so if they miss or skip any point in the class they may not be able to solve the worksheet completely and thereby lose reputation in the class.
Often students revise the chapter at home reading their respective textbooks. Thus more often than not they do miss many important points. Worksheets thus can be used intentionally to help guide student’s to consult textbooks. Having students write out responses encourages their engagement with the textbooks, the questions chosen indicate areas on which to focus. Explicitly discussing the worksheets and why particular questions are asked helps students reflect on what is important.