CBSE Class 12 Biology Previous Year Question Papers

Question Papers of Biology for Class 12 are the best tool to prepare for final examinations. These previous year papers and board papers are in accordance with CBSE guidelines and prescribed syllabus and thus after solving them students get enough confidence and practice to face the forthcoming exams. Here on Ribblu one can get lot of Question Papers for Class 12 Biology in PDF format for free

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 −
    • Types
    • Agencies
    • Examples
  • 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 −
    • Spermatogenesis
    • Oogenesis
  • 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 −
    • Humans
    • Birds
    • Honey bee
  • Linkage and crossing over
  • Sex linked inheritance −
    • Haemophilia
    • Colour blindness
  • Mendelian disorder in humans
    • Thalassemia
  • 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 −
    • Lac Operon
  • 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 −
    • Cancer
    • HIV
    • AIDs
  • 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

Question Papers of Other Subjects of Class 12

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In order to access the level of preparation done by any particular student he or she needs to solve Previous Year Question Papers. These papers act as perfect tools to practise for the final board exam. If one wants to get a clear look and feel of how final exam papers are framed in terms of level of difficulty, time and other aspects then , all students must make sure that they attempt these papers once their course revision is finished. Few benefits of solving Previous Question Papers are given below:

  • Revising the subject is very good practice but until and unless one Solves the past question papers in the lookalike environment as in board exam or final class room exam, there is most likely that student may not be able to identify and check whether the understanding of all concepts of the subject are complete or not. It is only after students attempt the question paper in the same time frame he or she is able to judge the capability of solving the paper in the stipulated time frame. It highlights the weak areas if any and gives students ample amount of time to work on those areas and be better prepared before exams.
  • Knowing everything is great but it is of no use unless the implementation and results are not matching with that. There is always a risk of the case in which in spite of knowing everything a student falls short of time to complete the entire question paper and thus loses marks. Generally CBSE Board papers and previous year questions are generally of 3 hour duration. So while practicing such papers it is imperative to create a final exam or board like environment at home and ensure that the Question paper is attempted only in 3 hours and then check whether it was possible to complete the paper in the desired amount of time. Often at first students take longer than expected, and thus they get early warning to practice more and increase the speed.
  • Students with anxiety issues need previous year papers more than anyone for overcoming such issues. Since they do not know what questions will be asked in the CBSE board they create panic in their mind due to this fear of the unknown and get scared with the idea that they might not be able to do well in exams. Thus such students need to complete at-least 7-10 Question papers prior to the exams, to gain confidence and get into a better frame of mind.