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Biology · Class 12 Science

Manipur Cohsem Class 12 Biology — Real Previous-Year Papers

with complete answers

Real previous-year board papers, year by year — the official exam pattern, the full question paper, and every question solved the concept-first way. Distinct from the chapter-wise textbook bank.

2016–2026
Years of papers
10
Total Papers
10
Real Board Papers
0
Sample papers
338
Real-paper Q & A
0
Sample-paper Q & A

Real board-paper questions available, by year

36 Q2026complete
36 Q2025complete
36 Q2024complete
34 Q2023complete
34 Q2022complete
—2021Not available
34 Q2020complete
34 Q2019complete
34 Q2018complete
34 Q2017complete
26 Q2016complete

COHSEM Manipur Higher Secondary Board 2026 · Set ANNUAL

Real board examination

About this paper

The real Class-12 board examination held in 2026. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks
70
Questions
36
Duration
180 min
Sections
5

The marks / questions / duration above are the official exam pattern. We currently have 36 of this paper’s questions (100% of the full paper), with 36 fully solved. Questions we couldn’t yet extract or verify are held — never shown as complete.

Sections & marks

SectionTypeQuestionsMarks eachTotal
ASection Acompulsory717
BSection Bcompulsory10110
CSection Ccompulsory10220
DSection Dcompulsory6318
ESection Ecompulsory3515
Total3670

The question paper

The questions we hold for this paper, laid out by section. Solutions are on the Answers tab.

Board Examination

Biology

COHSEM Manipur Higher Secondary Board 2026 · Set ANNUAL

Series/Set: ANNUALRoll No. ________
Time Allowed: 3 hoursMaximum Marks: 70

General Instructions

  1. This question paper contains 36 questions divided into 5 sections — A, B, C, D, E.
  2. Section A comprises 7 questions of 1 mark each (compulsory).
  3. Section B comprises 10 questions of 1 mark each (compulsory).
  4. Section C comprises 10 questions of 2 marks each (compulsory).
  5. Section D comprises 6 questions of 3 marks each (compulsory).
  6. Section E comprises 3 questions of 5 marks each (compulsory).

Above is the official exam pattern. The questions printed below are those we currently hold for this paper.

Section A

compulsory · 1 mark each · 17 of 7 shown

Q1.
The remaining parts of the Graafian follicle after ovulation change into –
  • (a) Corpus luteum
  • (b) Ovum
  • (c) Oocyte
  • (d) Secondary Oocyte
[1]
Q2.
β - Thalassemia is controlled by a single gene HBB on –
  • (a) Chromosome 16
  • (b) Chromosome 13
  • (c) Chromosome 11
  • (d) Chromosome 14
[1]
Q3.
Haemozoin is released as a result of –
  • (a) Rupture of liver cells
  • (b) Rupture of red blood cells
  • (c) Multiplication of sporozoites
  • (d) Replication in macrophages
[1]
Q4.
The enzyme required for isolating DNA from fungi is –
  • (a) Cellulase
  • (b) Chitinase
  • (c) Lysozyme
  • (d) Endonuclease
[1]
Q5.
The possible reason for extinction of Steller's sea cow is due to –
  • (a) Alien species invasion
  • (b) Over exploitation
  • (c) Habitat Loss
  • (d) Co-extinction
[1]
Q6.
Which one of the following involves the transfer of genetically different pollen grains to the stigma?
  • (a) Geitonogamy
  • (b) Cleistogamy
  • (c) Chasmogamy
  • (d) Xenogamy
[1]
Page 1 of 5
Q7.
Identify the effect brought about by single step large mutation in evolution from the options given below : (a) Saltational speciation (b) Founder effect (c) Gene migration (d) Evolution by special creation
[1]
Q8.
Which one of the following is commonly found in root ecosystem and control several plant pathogens? (a) Rhizobium (b) Bacillus thuringiensis (c) Trichoderma (d) Azospirillum
[1]
Q9.
Assertion : Ligase enzyme is used to join a foreign gene with a cloning vector. Reason : Ligase forms phosphodiester bonds between complementary base pairs. (a) If both Assertion and Reason are true and Reason is a correct explanation of the Assertion. (b) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. (c) If Assertion is true but Reason is false. (d) If both Assertion and Reason are false.
[1]
Q10.
Assertion : The pyramid of energy is always upright. Reason : At each trophic level some energy is lost as heat. (a) If both Assertion and Reason are true and Reason is a correct explanation of the Assertion. (b) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. (c) If Assertion is true but Reason is false. (d) If both Assertion and Reason are false.
[1]
Q11.
State the type of interaction that exists between sea anemone and clown fish.
[1]
Q12.
Why is mother's milk considered very essential for the new-born infants?
[1]
Q13.
How does an endoparasite differ from an ectoparasite?
[1]
Q14.
Give one reason how the condition of a patient suffering from myocardial infarction can be improved by administering the bioactive agent Streptokinase.
[1]
Q15.
Analyse how trisomy of chromosome 21 occurs in Down's Syndrome.
[1]
Q16.
“Smoking causes oxygen deficiency in human body”. Justify the statement.
[1]
Page 2 of 5
Q17.
Give reason for moving DNA fragments towards the anode in gel electrophoresis.
[1]
Section B

compulsory · 1 mark each · 10 of 10 shown

Q1.
Where are untranslated regions (UTRs) located in m-RNA? State their function.
[2]
Q2.
What is the name of the first antibiotic and from which organism was it obtained?
[2]
Q3.
Explain the mechanisms by which copper and hormone releasing IUDs prevent pregnancy.
[2]
Q4.
What are the differences between Klinefelter's syndrome and Turner's syndrome in terms of their causes and karyotypes?
[2]
Q5.
Differentiate between Benign and Malignant tumors with reference to their metastatic and severity of damaging tissue.
[2]
Q6.
“The co-evolution of figs and wasps provides benefits to both through mutualism”. Give two benefits for the wasps.
[2]
Q7.
Suggest the functions of lymphocytes in the immune responses against a specific pathogen.
[2]
Page 3 of 5
Q8.
Predict how the transfer of a recombinant DNA bearing an antibiotic resistance gene determine the host E.coli as a transformant or non-transformant.
[2]
Q9.
Draw a neat diagram of enlarged view of one microsporangium and label tapetum.
[2]
Q10.
Draw a neat diagram of a cloning vector pBR322 and label BamH I.
[2]
Section C

compulsory · 2 marks each · 6 of 10 shown

Q1.
Describe the process of natural selection in both white winged and melanised winged moths during pre and post industrialisation period in England.
[3]
Q2.
Explain the process of silencing the m-RNA of nematode Meloidogyne incognita to provide protection to the host plant.
[3]
Q3.
Summarize with three suitable examples how the invasion of alien species causes the decline or extinction of indigenous species.
[3]
Q4.
“The continuity of pregnancy in a woman's body requires the development of the placenta between maternal body and developing embryo”. Give three probable reasons.
[3]
Page 4 of 5
Q5.
In a DNA molecule, adenine makes 30%. How many guanine bases will be present in the DNA containing 3000 nucleotides?
[3]
Q6.
Case study : Suresh, 30 years old man was admitted to the hospital with symptoms of fever, chills, cough, headache and difficulty in breathing for the last few days. His chest X-ray shows fluid accumulation in the lungs and was diagnosed pneumonia. He was treated with medicines and advised complete rest. Questions : (a) How does pneumonia spread? (1 mark) (b) Identify two likely causative organisms of pneumonia. (2 marks)
[3]
Section D

compulsory · 3 marks each · 3 of 6 shown

Q1.
Explain the neuroendocrine mechanism that induces parturition in humans.
[5]
Q2.
Explain how t-RNA acts as an adapter molecule during translation.
[5]
Q3.
“Ex-situ conservation practices can significantly reduce the very high risk of extinction of threatened animals and plants in the wild”. Analyse.
[5]
Page 5 of 5