Which Chapter is the Most Important in Biology Question Bank For CBSE Class 12 Exam 2025?

Brief About the Biology CBSE Class 12  

The revised syllabus of Biology class 12 CBSE 2024-25 is prepared by the NCERT. It has taken enough measures to ensure the students are provided with concepts that will help them understand the subject. 

With the help of the CBSE class 12 Biology textbook, students can organize their exam preparation method and figure out which chapters require extra focus.  

The syllabus helps students to understand the syllabus framework faster and to prepare them well for the exams. This article covers everything you need to know about:

• Important topics of Biology as per the updated syllabus
• List of a few important questions about the Biology exam paper 
• Detailed information about the Biology textbook for class 12 and Biology Question Bank for class 12 to help you score 90+ marks in the CBSE board exam 2024-25. 

Read further to know more. 

Importance Of Studying Biology Chapter-wise  

CBSE released the Biology Class 12th Syllabus 2024-25 to help students as you prepare efficiently for the 2024-25 board exams. 

The board will make the question papers as per the syllabus, so students need not worry if any questions will be out of the syllabus. 

Before we discuss the important chapters of Biology for class 12, let’s first understand the marking scheme as prescribed by the CBSE board for the 2024-25 exam. 

Marking Scheme Of Class 12 Biology 2024-25  

The exam is divided into 2 parts: 

Theory: 70 marks 

Practicals: 30 marks

PRACTICALS – 3 Hours 

A. List of experiments as stated above: 

1. Prepare a temporary mount to observe pollen germination.
2. Study the plant population density by quadrat method.
3. Study the plant population frequency by quadrat method.
4. Prepare a temporary mount of onion root tip to study mitosis.
5. Isolate DNA from available plant material such as spinach, green pea seeds, papaya, etc.

B. Spotting:

1. Flowers adapted to pollination by different agencies (wind, insects, birds).
2. Pollen germination on stigma through a permanent slide or scanning electron micrograph.
3. Identification of stages of gamete development, i.e., T.S. of testis and T.S. of ovary through permanent slides (from grasshopper/mice).
4. Meiosis in onion bud cell or grasshopper testis through permanent slides.
5. T.S. of blastula through permanent slides (Mammalian).
6. Mendelian inheritance using seeds of different colour/sizes of any plant.
7. 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.
8. Controlled pollination – emasculation, tagging and bagging.
9. Common disease-causing organisms like Ascaris, Entamoeba, and Plasmodium are any fungus-causing ringworm through permanent slides, models, virtual images, or specimens. Comment on symptoms of diseases that they cause.
10. Models specimen showing symbolic association in root modules of leguminous plants, Cuscuta on host, lichens.
11. Flash card models showing examples of homologous and analogous organs.

General practical know-hows: 

1. The format of writing any experiment in the practical file should include aim, apparatus required, simple theory, procedure, related practical skills, precautions, etc.

2. The viva questions may include questions based on basic theory/principle/concept, apparatus/materials/chemicals required, procedure, precautions, sources of error, etc.

Practice Materials: Biology Class 12 Textbook & Biology 12th Question Bank

Gurukul by Oswal Biology Question Bank for CBSE Class 12 for the 2025 exam is one of the best practice materials you can trust.

It consists of chapter-wise & unit-wise questions and answers as per the latest syllabus issued on 23rd March 2024. 

Biology CBSE Class 12 Question Bank highlights: knowledge-based and skill-based questions to prepare the subject in depth that will help you get better in Biology.  

It is: 

1. As per the updated and new pattern prescribed by the board 

2. Includes previous years’ question papers that will help you analyze the patterns 

3. Has a wide variety of MCQs, extract-based, Very Short/Short/Long Answer Type Questions

4. A chapter-wise summary that will help you with quick revision 

5. Complete explanation to all MCQs so that you don’t have to consult any other book. 

6. NCERT and NCERT Exemplar Question Inculded

7. Competency-based Questions

The Question Bank is the most comprehensive guide and has numerous tips and tools to improve study techniques for any exam paper. 

Students can create vision boards to establish study schedules and maintain study logs to measure their progress. 

Other resources and Biology class 12 textbook includes: 

• Class 12 PCB students can refer to CBSE Question Bank Class 12 Bundles (Set Of 4) Physics, Chemistry & Biology For Exam 2025.

• You can also consult Gurukul by Oswal Science (PCB) Last Years’ 10 Solved Papers CBSE Class 12 For the 2025 Exam. 

For further guidance, check out the top study tips for Class 12 Science students to prepare for CBSE Board exam 2024-25.

Important Chapters As Per The Syllabus Of Biology For Class 12 CBSE 2024-25

Here are unit-wise and chapter-wise of CBSE Class 12 Biology Syllabus 2025. 

CBSE Class 12 Biology Syllabus 2025: Unit 6 – Reproduction

Chapter-2: Sexual Reproduction in Flowering Plants

Flower structure; development of male and female gametophytes; pollination – types, agencies, and examples; out breeding devices; pollen-pistil interaction; double fertilization; post-fertilization events – development of endosperm and embryo, development of seed and formation of fruit; special modes- apomixis, parthenocarpy, polyembryony; Significance of seed dispersal and fruit formation.

Chapter-3: Human Reproduction

Male and female reproductive systems; microscopic anatomy of testis and ovary; gametogenesis -spermatogenesis and 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 (STDs); birth control – need and methods, contraception and medical termination of pregnancy (MTP); amniocentesis; infertility and assisted reproductive technologies – IVF, ZIFT, GIFT (Elementary idea for general awareness).

CBSE Class 12 Biology Syllabus 2025: Unit 7 – Genetics and Evolution

Chapter-5: Principles of Inheritance and Variation

Heredity and variation: Mendelian inheritance; deviations from Mendelism – incomplete dominance, co-dominance, multiple alleles and inheritance of blood groups, pleiotropy; elementary idea of polygenic inheritance; chromosome theory of inheritance; chromosomes and genes; Sex determination – in humans, birds and honey bee; linkage and crossing over; sex linked inheritance – haemophilia, colour blindness; Mendelian disorders in humans thalassemia; chromosomal disorders in humans; Down’s syndrome, Turner’s and 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, Human and rice genome projects; DNA fingerprinting.

Chapter-7: Evolution

Origin of life; biological evolution and evidence for biological evolution (paleontology, comparative anatomy, embryology, and molecular evidence); Darwin’s contribution, modern synthetic theory of evolution; mechanism of evolution – variation (mutation and recombination) and natural selection with examples, types of natural selection; Gene flow and genetic drift; Hardy – Weinberg’s principle; adaptive radiation; human evolution.

CBSE Class 12 Biology Syllabus 2025: Unit 8 – Biology and Human Welfare

Chapter 8: Human Health and Diseases

Pathogens; parasites causing human diseases (malaria, dengue, chikungunya, filariasis, ascariasis, typhoid, pneumonia, common cold, amoebiasis, ring worm) and their control; Basic concepts of immunology – vaccines; cancer, HIV and AIDS; Adolescence – drug and alcohol abuse.

Chapter 10: Microbes in Human Welfare

Microbes in food processing, industrial production, sewage treatment, energy generation and microbes as bio-control agents and bio-fertilizers. Antibiotics; production and judicious use.

CBSE Class 12 Biology Syllabus 2025: Unit 9 – Biotechnology and its Applications

Chapter 11: Biotechnology – Principles and Processes

Genetic Engineering (Recombinant DNA Technology).

Chapter 12: Biotechnology and its Applications

Application of biotechnology in health and agriculture: Human insulin and vaccine production, stem cell technology, gene therapy; genetically modified organisms – Bt crops; transgenic animals; biosafety issues, biopiracy and patents.

CBSE Class 12 Biology Syllabus 2025: Unit 10 – Ecology and Environment

Chapter 13: Organisms and Populations

Population interactions – mutualism, competition, predation, parasitism; population attributes – growth, birth rate and death rate, age distribution. (Topics excluded: Organism and its Environment, Major Aboitic Factors, Responses to Abioitic Factors, Adaptations)

Chapter 14: Ecosystem

Ecosystems: Patterns, components; productivity and decomposition; energy flow; pyramids of number, biomass, energy (Topics excluded: Ecological Succession and Nutrient Cycles)

Chapter 15: Biodiversity and its Conservation

Biodiversity-Concept, patterns, importance; loss of biodiversity; biodiversity conservation; hotspots, endangered organisms, extinction, Red Data Book, Sacred Groves, biosphere reserves, national parks, wildlife, sanctuaries, and Ramsar sites.

List of Few Important Questions of Biology Class 12 CBSE 2024-25  

The CBSE has designed the Class 12 Biology Syllabus 2025 in such a way that you as students can prepare for the Competency-based questions that will actually be useful even after you pass your exam. 

The typology of questions are: 

• Very short answers (VSA) that include MCQs
• Assertion-based and reasoning type questions
• Short answers of 1, 2, 3, and 5 marks
• Long answers, fill in the blanks 
• Source-based, case-based, passage-based and other integrated assessment questions.

The subject matter experts have prepared the important questions for Class 12 Biology to help students in their board 2024-25 exam preparations. These important questions provide a strategy to excel. 

The listed are a few questions from each chapter of Gurukul by Oswal Biology Question bank, per the NCERT’s textbook. 

Buy Gurukul by Oswal Biology Question Bank for CBSE Class 12 for the 2025 exam today! 

Multiple Choice Questions 

• Which one of the following parts of the plant, when put into the soil, is likely to produce new offspring?
• One of the most resistant biological materials is—
• Filiform apparatus in the embryo sac of an angiosperm is present at the micropylar tip of—
• Urethral meatus refers to the–
• Prostate gland is present—
• Corpus luteum develops from— 
• Which one of the following groups includes all sexually transmitted disease?
• Reproductive health in society can be improved by—
• Lactational amenorrhoea is effective only up to a maximum period of–
• Artificial insemination means–
• ZIFT is the transfer of–
• In a DNA strand, the nucleotides are linked together by–
• Who discovered DNA polymerase?
• The protein of DNA, which contains information for an entire polypeptide, is called as—
• Theory of the chemical origin of life was prepared by–
• What is the first sign or symptom of tetanus? 
• What does the second critical research area of biotechnology provide?
• Who is referred to as the Father of Ecology in India?

Assertion and Reasoning Based Questions

• Assertion: Pollination by bats is known as chiropterophily.

Reason: Pollination by birds is known as ornithophily.

• Assertion: In a microsporangium, the tapetal cells possess little cytoplasm and generally have a single prominent nucleus. 

Reason: During microsporogenesis, the microspore mother cells undergo mitotic divisions to produce haploid microspore tetrads. 

• Assertion: During pregnancy, the development of fetus occurs in stages.

Reason: In the second month of pregnancy, limbs, most of the organs, and external genitalia are formed

• Assertion: The sex of the baby is determined by the father and not by the mother.

Reason: 50% of sperms carry the sex chromosome X while the other 50% carry the sex chromosome Y.

• Assertion: Vitamin B12 is found in cereals, green vegetables, brewer’s yeast, eg white, milk and liver.

Reason: It can be commercially produced by some yeasts

• Assertion: Nitrogenase enzyme gets inactivated in the presence of oxygen, yet N2

fixation occurs in aerobic cells of legume nodules.

Reason: Leghaemoglobin allows the presence of oxygen just sufficient for cellular respiration only.

Reasoning-based Questions 

• In early days, patients taking external insulin used to show certain allergies and related reactions. Why was this so?

Definitions 

• Define artificial insemination
• Define vasectomy and tubectomy

 One Word Answer Type Questions

• Diseases which are transmitted through sexual intercourse are referred as–
• Inability to conceive or produce a child even after two years of unprotected sexual cohabitation is medically termed as–

Expansion of the Abbreviations

• Expand GLU and VAL 
• What is chitinase?

Difference Between 

• Distinguish between Hibernation and Aestivation
• Difference between Ectotherms and Endotherm

Very Short Answer Type Questions

• Mention the two contrasting flowers related traits studied by Mendel in his pea plan experiment
• A male honeybee has 16 chromosomes, whereas a female has 3 chromosomes. Give one reason
• State what aneuploidy leads to. 
• Regarding Streptococcus pneumonia, what is the difference between S strain and R strain?
• Explain the two factors responsible for conferring stability to the double helix structure of DNA
• List ten recombinant proteins used in medical practice. Also, mention where they are used as therapeutics.

Evaluation and Analysis-Based Questions

• An amount of biomass or organic matter produced by the process o photosynthesis, per unit area, per unit time is _________.
• Before attaining the climax community, the primary succession in water ends  with the growth of _________. 

Source and Passage-Based Questions

The process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. Explain adaptive radiation with the help of a suitable example.

To know the explanation behind these questions, buy:

• Biology Question Bank
• PCB last 10 years solved question papers
• CBSE bundle having Biology, Chemistry & Physics and start strengthening your knowledge! 

Scoring A+ in CBSE Boards 2024-25 Biology Got Easier

We hope this article gave you a clearer idea of the types of questions you might get in the CBSE boards 2024-25 Biology exam. 

You have plenty of time, so make the best of it before your exam. Check this detailed guide about 37 proven time management tips to help you manage your time properly. 

Let us know if you need help. 🙂 

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