CBSE Class 12 Biology Set 3 - (57/1/3) Question Paper 2026 is available for download here. CBSE conducted Class 12 Biology exam on March 27, 2026 from 10:30 AM to 1:30 PM. The Biology theory paper is of 70 marks, and the internal assessment is of 30 marks.
Also Check: CBSE Class 12 Question Paper 2026 (All Subjects)
Biology question paper includes the following types of questions:
- MCQs: 1 mark each
- Short-answer type questions: 2 & 3 marks each
- Case-study based questions: 4 marks each
- Long-answer type questions: 5 marks each
- Total: 70 marks
CBSE Class 12 Biology Question Paper 2026 (Set 3 - 57/1/3) with Solution PDF
| CBSE Official PDF | CD PDF | CD PDF with Solutions |
|---|---|---|
| Download official PDF 1.60 MB | Download Collegedunia PDF 0.89 MB | – |
CBSE Class 12 Biology 2026 Set 3 (57/1/3) Questions with Solutions
Interferons are most effective in making non-infected cells resistant against the spread of which of the following diseases ?
Which of the following sacred groves is found in Meghalaya?
In an ecosystem, different species occupy different levels and vertical distribution of species is found. This is called ______.
Which of the following statements about plasmids is incorrect?
Which connective tissue connects ovary to pelvic wall and uterus?
Select the option that shows correct statements :
(i) Corpus luteum secretes progesterone.
(ii) Only FSH attains a peak level in middle of cycle.
(iii) LH surge induces rupture of graafian follicle.
(iv) Luteal phase of menstrual cycle is also called proliferative phase.
Which one of the following evidences does not support Darwin's theory of natural selection ?
Expression of a particular gene helps to identify transformants. What is this gene known as ?
A DNA molecule is 140 base pairs long. It has 20% thymine. How many guanine bases are present in the molecule ?
Select the mismatched pair :
Pomato was produced by fusing protoplasts of
Assertion (A): Fossils provide direct evidence for evolution.
Reason (R): Fossils help to trace evolutionary relationships among organisms over time.
Assertion (A) : In terrestrial ecosystem much larger fraction of energy flows through grazing food chain.
Reason (R) : Grazing food chain may be connected to Detritus food chain at some levels.
Assertion (A) : The milk produced by transgenic cow 'Rosie' was nutritionally more balanced product for human babies than natural cow milk.
Reason (R) : It was human protein enriched milk containing human alpha lactaglobulin.
Assertion (A) : Flocs are masses of bacteria associated with fungal filaments in secondary treatment of sewage.
Reason (R) : Flocs help in digestion of solid waste by anaerobic respiration.
A health officer visiting two different regions reported the following symptoms in patients :
Region A - Sustained high fever with stomach pain, constipation and loss of appetite.
Region B - Inflammation in the lower limbs and genital organs.
Name the diseases likely affecting the patients in regions A and B. Write the scientific name of the causative organisms in both the cases.
Identify the stage of follicle where primary oocyte undergoes first meiotic division. Also mention the products of this division.
(i) How does a farmer use dormancy of seed to his advantage ?
(ii) Differentiate between pea seed and castor seed.
Mendel published his work on inheritance in 1865, but it remained unnoticed for over three decades.
State the reasons why his work was not recognised during his life time. (4 points)
(i) What is primary productivity of an ecosystem and how is it expressed ?
(ii) Explain the equation given below :
NPP = GPP - R
Biodiversity conservation is crucial for maintaining ecological balance and ensuring the survival of future generations.
Describe four advanced ex-situ methods used for conservation of biodiversity.
Observe the given picture carefully. A mixture of DNA with fragments ranging from 100 base pairs to 1800 base pairs were separated by electrophoresis on agarose gel with the following arrangement:
Observe the given picture carefully. A mixture of DNA with fragments ranging from 100 base pairs to 1800 base pairs were separated by electrophoresis on agarose gel with the following arrangement :
(a) What result will be obtained in staining with ethidium bromide ? Explain with reasons.
Observe the given picture carefully. A mixture of DNA with fragments ranging from 100 base pairs to 1800 base pairs were separated by electrophoresis on agarose gel with the following arrangement :
(b) The above setup was modified as shown below and a band with 100 base pairs was obtained at X.
What changes were made to the previous design to get a band at ‘X’ ? Why did the band appear at ‘X’ ?
Mention the scientific name of the source plant and the part from which opioids are extracted.
How are morphine and heroin related? Mention the effect each of them has on human body.
Do all pollen grains remain viable for the same length of time? Support your answer with two suitable examples.
How are pollen grains stored in pollen banks?
What is pedigree analysis? Mention its importance in human genetics. (2 pts.)
Analyse the following pedigree and write the (i) Pattern of inheritance. (ii) Give one example of disease showing such an inheritance pattern.
List any two factors that disturb the genetic equilibrium.
How is Hardy-Weinberg expression (\(p^{2} + 2pq + q^{2} = 1\)) derived?
Suggest and describe a technique through which a healthy sugarcane plant can be obtained from virus infected sugarcane plant.
Draw a neat diagram of megasporangium of an angiosperm and label any six parts.
Identify and define the ecological phenomenon demonstrated by this observation.
State the principle that explains the elimination of one species.
Two different species can compete for the same resource. Give another example of it.
How do species avoid competition in nature? Explain with an example.
A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions:
A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions :
What can you infer about the genotype of parents in crosses I and II ?
A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions :
Which genetic cross is represented by these crosses ?
A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions :
Looking at bar graph of cross III, identify the type of cross performed and its importance in genetics.
A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions :
(c) What conclusion can you draw from the results of bar graphs of crosses I and II ? Name the genetic principle illustrated.
Name the different types of microorganisms used as bio-fertilizers in organic farming and explain how each contributes to soil fertility.
What are bio-fertilizers?
Write two advantages of using bio-fertilizers over chemical fertilizers.
(i) Name the protozoan species that is responsible for causing the most serious and even fatal malarial disease.
(ii) Name the host in which the parasite completes its sexual stages and explain the changes taking place.
(iii) How does the parasite damage the human body after entering the blood stream ?
(iv) Suggest two effective preventive measures to control the spread of this disease in endemic regions.
Describe how the lac operon operates both in the presence and absence of an inducer in E.coli.
(i) Differentiate between Mendelian and Chromosomal disorders.
(ii) Which disorder is known as "Inborn Error of Metabolism" ? Mention its cause and any one symptom. Name the harmful compounds formed.
Trace the events from fertilization till implantation of blastocyst in human female. Also mention the site where fertilization takes place.
Case studies of some couples are given below. They were not able to have kids even though the parents were not taking any precautions. They also do not wish to adopt a child or take the help of donors. Study these cases and suggest an appropriate Assisted Reproductive Technology that could help them.
Case I -- Female -- Normal Reports; Male -- Normal sperms but no connection between epididymis and vas deferens.
Case II -- Female -- Normal eggs but Fallopian tube blocked. Male -- Normal sperms. Male reports are normal.
Case III -- Female -- Normal Reports. Male -- Low sperm count with less motility.
Copper releasing intrauterine devices are very effective and popular contraceptive devices. Name any two copper releasing IUDs. Write two reasons that make them effective contraceptives.
CBSE Class 12 Biology Question Paper Pattern and Marking Scheme
The CBSE Class 12 Biology 2026 question paper is of 70 marks and has 33 questions in five sections, A to E, all compulsory. The tables below give the section-wise paper pattern and the marking rules from the official CBSE marking scheme.
CBSE Class 12 Biology Question Paper Pattern 2026
| Section | Questions | Question Type | Marks per Question | Marks |
|---|---|---|---|---|
| A | Q1 - Q16 | Multiple choice questions | 1 | 16 |
| B | Q17 - Q21 | Very short answer type | 2 | 10 |
| C | Q22 - Q28 | Short answer type | 3 | 21 |
| D | Q29 - Q30 | Case-based questions | 4 | 8 |
| E | Q31 - Q33 | Long answer type | 5 | 15 |
| Total | 33 questions | 70 |
CBSE Class 12 Biology Marking Scheme 2026
| Marking point | How it is applied |
|---|---|
| Value-point marking | Marks are awarded against the value points (steps) given in the official marking scheme; the marks of an answer are split across its steps. |
| Own expression | The marking scheme carries suggested value points only. A correct answer in the student's own words is awarded due marks. |
| Competency-based questions | If a competency-based answer is not from the marking scheme but shows the correct competency, due marks are awarded. |
| Errors | An error is penalised only once; no marks are deducted for its cumulative effect. |
| Incorrect answer | A totally incorrect answer is awarded zero (0) marks. |
| Choice (OR) questions | If both options of a question with internal choice are attempted, marks are awarded for both and the higher score is taken; if only one option is attempted, the other is marked NA (not attempted). |
| Scale of marks | The full scale of 0 to 70 marks is used and full marks are awarded whenever the answer deserves them. |
CBSE Class 12 Biology Unit-Wise Weightage
| Unit No. | Unit Name | Marks |
|---|---|---|
| VI | Reproduction | 16 |
| VII | Genetics and Evolution | 20 |
| VIII | Biology and Human Welfare | 12 |
| IX | Biotechnology and Its Applications | 12 |
| X | Ecology and Environment | 10 |
| Total | — | 70 |
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