CBSE Class 12 Board Exam Biology Syllabus

Biology syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Biology in CBSE Class 12 Board Exam, not a summary of it.

1. 1

   Reproduction

   3 topics

   • Sexual Reproduction in Flowering Plants
     • Structure of flower and pollination
     • Double fertilisation
     • Post-fertilisation events and apomixis
   • Human Reproduction
     • Male and female reproductive systems
     • Gametogenesis and menstrual cycle
     • Fertilisation, implantation and pregnancy
   • Reproductive Health
     • Contraception and birth control
     • Sexually transmitted infections
     • Assisted reproductive technologies
2. 2

   Genetics and Evolution

   3 topics

   • Principles of Inheritance and Variation
     • Mendelian inheritance and deviations
     • Chromosomal theory and linkage
     • Sex determination and genetic disorders
   • Molecular Basis of Inheritance
     • DNA structure and replication
     • Transcription and translation
     • Gene regulation (lac operon) and Human Genome Project
   • Evolution
     • Origin of life and evidences for evolution
     • Darwinism and Hardy-Weinberg principle
     • Human evolution
3. 3

   Biology and Human Welfare

   3 topics

   • Human Health and Disease
     • Pathogens and common diseases
     • Immunity and vaccines
     • AIDS, cancer and drug abuse
   • Microbes in Human Welfare
     • Microbes in household products
     • Microbes in industrial products and sewage treatment
     • Biofertilisers and biocontrol agents
   • Ecosystem and Biodiversity
     • Ecosystem structure and energy flow
     • Ecological pyramids and nutrient cycling
     • Biodiversity and conservation
4. 4

   Biotechnology

   3 topics

   • Biotechnology - Principles and Processes
     • Recombinant DNA technology and tools
     • Restriction enzymes and cloning vectors
     • PCR and gel electrophoresis
   • Biotechnology and its Applications
     • Genetically modified organisms
     • Bt crops and gene therapy
     • Biosafety and patents
   • Tools and Processes in Genetic Engineering
     • Isolation of genetic material
     • Bioreactors and downstream processing
     • Transformation and selection of recombinants

Biology flashcards for CBSE Class 12 Board Exam

22 of 77 cards from the Biology deck — real questions with worked answers.

1. In a flowering plant, what is the function of the tapetum in the anther?

   The tapetum is the innermost wall layer of the microsporangium; it nourishes the developing pollen grains (microspores).

2. What is the typical structure of a mature pollen grain (male gametophyte) before pollen tube formation?

   It is 2-celled: a large vegetative (tube) cell and a small generative cell. In some species it is 3-celled when shed.

3. Describe the structure of a typical mature embryo sac in angiosperms.

   It is 7-celled and 8-nucleate: one egg cell + two synergids (egg apparatus) at the micropylar end, three antipodal cells at the chalazal end, and one central cell with two polar nuclei.

4. What is double fertilization in angiosperms?

   One male gamete fuses with the egg (syngamy) to form the diploid zygote, and the other fuses with the two polar nuclei (triple fusion) to form the triploid primary endosperm nucleus.

5. Differentiate geitonogamy from xenogamy.

   Geitonogamy is pollination between two flowers of the same plant (genetically self-pollination). Xenogamy is pollination between flowers of two different plants (true cross-pollination).

6. What is apomixis?

   Apomixis is the production of seeds without fertilization; it is a form of asexual reproduction that mimics sexual reproduction.

7. In sexual reproduction in flowering plants, what is the ploidy of the endosperm, zygote, nucellus, and antipodal cells?

   Endosperm: triploid (3n); zygote: diploid (2n); nucellus: diploid (2n); antipodal cells: haploid (n).

8. Name the part of the human male reproductive system where sperm are produced and where they mature/are stored.

   Sperm are produced in the seminiferous tubules of the testes; they mature and are stored in the epididymis (and stored in vas deferens).

9. What is spermiogenesis versus spermiation?

   Spermiogenesis is the transformation of spermatids into mature spermatozoa. Spermiation is the release of sperm from the seminiferous tubules into the lumen.

10. Which cells in the testis secrete testosterone, and which support and nourish the developing germ cells?

    Leydig (interstitial) cells secrete testosterone; Sertoli cells support and nourish the developing germ cells.

11. During which phase of meiosis is the secondary oocyte arrested until fertilization in humans?

    The secondary oocyte is arrested at metaphase of meiosis II; it completes meiosis II only if fertilization occurs.

12. What hormones surge to trigger ovulation, and on roughly which day of a 28-day menstrual cycle does ovulation occur?

    A surge in LH (and FSH) triggers ovulation, which occurs around day 14 of a 28-day cycle.

13. What is the structure that connects the embryo to the placenta, and name two functions of the placenta.

    The umbilical cord connects the embryo to the placenta. The placenta supplies nutrients and oxygen, removes wastes, and acts as an endocrine gland (secreting hCG, hPL, estrogen, progesterone).

14. What hormone is detected in pregnancy tests and is secreted by the developing embryo/placenta?

    Human chorionic gonadotropin (hCG).

15. What is the process of milk production from mammary glands after childbirth called, and what is the first milk rich in antibodies?

    Milk production is lactation; the first milk, colostrum, is rich in antibodies (especially IgA) providing passive immunity to the newborn.

16. Distinguish between IUDs and oral pills as contraceptive methods by their mode of action.

    IUDs (e.g., Cu-T) act locally in the uterus—increasing phagocytosis of sperm and making the endometrium unsuitable for implantation. Oral pills are hormonal, inhibiting ovulation and implantation and altering cervical mucus.

17. What does the technique 'amniocentesis' detect, and why is its misuse legally banned in India?

    Amniocentesis analyzes fetal cells in amniotic fluid to detect chromosomal/genetic disorders. It is banned for sex-determination because of misuse for female foeticide.

18. Differentiate ZIFT from IUT in assisted reproductive technologies.

    ZIFT (Zygote Intra-Fallopian Transfer) transfers a zygote or early embryo (up to 8 blastomeres) into the fallopian tube. IUT (Intra-Uterine Transfer) transfers an embryo with more than 8 blastomeres into the uterus.

19. What is GIFT in assisted reproduction?

    GIFT (Gamete Intra-Fallopian Transfer) is the transfer of an ovum (collected from a donor) into the fallopian tube of a female who cannot produce eggs but can provide a suitable environment for fertilization and development.

20. Name two common sexually transmitted infections that are completely curable if detected early and two that are not easily curable.

    Curable if detected early: gonorrhea, syphilis, chlamydiasis (also trichomoniasis). Not easily curable: HIV/AIDS, genital herpes, hepatitis-B.

21. State Mendel's Law of Segregation.

    The two alleles of a gene separate (segregate) during gamete formation so that each gamete receives only one allele of each gene.

22. State Mendel's Law of Independent Assortment.

    During gamete formation, alleles of different genes assort independently of one another (applies to genes on different chromosomes).

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