🦠 12th Zoology Important Two Mark Questions – Public Exam 2025

📚 Ace Your Zoology Exam with Important 2-Mark Questions!
Prepare for the 12th Zoology Public Exam 2025 with chapter-wise important two-mark questions, selected from previous year board exam papers and high-scoring topics. These questions help students revise key concepts and secure easy marks in the exam.

🔹 Chapter-wise 2-mark questions with answers
🔹 Based on Tamil Nadu Board syllabus
🔹 Covers Human Physiology, Genetics, Evolution & Biotechnology
🔹 Essential for quick revision & high scores

Chapter 3 : Reproductive Health

1. Explain ZIFT and GIFT?Ln3 Pg39
2. What is meant by mayer – rokitansky syndrome?Ln3 Pg39
3. What is vasectomy?Ln3 Pg35
4. What is Female foeticide?Ln3 Pg33
5. List out copper releasing IVD’s?Ln3 Pg35
6. Mention any one viral STI and srite its symptoms?Ln3 pg37
7. Which one is called as anti – sterility vitamin?why?Ln3 Pg41
8. IUT – write notes?Ln3 pg40

Chapter 4 : Principles of Inheritance and Variation

1. Extra chromosomal inheritance?Ln4 Pg55
2. What is sex linked inheritance?Ln4 Pg51
3. What is haplodiploidy?Ln4 Pg51
4. What is Extra chromosomal or cytoplasmic inheritance?Give example?Ln4 Pg55
5. What is Eugenics? What are its types?Ln4 pg56

Chapter 5 : Molecular Genetics

1. Differentiate nucleoside and nucleotide?Pg62
2. What are ribosomes?Ln5
3. Define operon?Ln5 Pg81
4. What is Transcription?Ln5 pg71
5. Draw the schematic structure of a transcription unit?Ln5 Pg72

Chapter 6 : Evolution

1. What are Atavistic organs?Ln6 Pg98
2. What is lamarck theory?Ln6 Pg99

Chapter 7 : Human Health and Diseases

1. Why do you think it is not possible to produce vaccine against common cold?Pg109 Pg114
2. List the common withdrawal symptoms of drugs and alcohol abuse?Ln7 Pg122
3. What are the symptoms of mental depression?Ln7 pg124
4. Write the impact of participating in an exercise programme?Ln7 Pg124

Chapter 8 : Immunology

1. Where are adenoids located?write about its function?Ln8 Pg134
2. Define interferons?Ln8 BB19
3. Write notes on Brewer’s yeast?Pg141 Pg151
4. What is metastasis?Ln8 pg142

Chapter 9 : Microbes in Human Welfare

1. Differentiate Prebiotics and probiotics?Ln9 Pg149
2. What is Ex-Situ conservation?Ln9 Pg154
3. Define super bug?Ln9 Pg150

Chapter 10 : Applications of Biotechnology

1. What are patents?Ln10 Pg171
2. What is PCR?Ln10 Pg164
3. What is Elisa?write its types?Ln10 Pg163 & 164
4. What are DNA vaccines?Ln10 Pg160

Chapter 11 : Organisms and Populations

1. Define Natality and Mortality?Ln11 Pg188
2. Define Bergmann’s rule?Ln11 Pg 178
3. Define Birth rate and Death rate?Ln11 Pg188

Chapter 12 : Biodiversity and its Conservation

1. What are gene Banks?What is its significance?Ln12 Pg213
2. What is Bio-Diversity conservation?Pg214 Ln12
3. “Amazon forest is considered to be the lungs of the planet”-Justify this statement.Ln12 BB14

Chapter 13 : Environmental Issues

1. What is smog and how is it harmful to us?Ln13 Pg222
2. What are the remedies of plastic waste?Ln13 Pg233

Additional important Two Marks

1. What is Bio-Diversity conservation?Pg214 Ln12
2. Mention the symptoms of phenylketoneuria?BB28 BB31
3. Write notes on one-gene one enzyme hypothesis?Pg59Pg62
4. Write the preventive measures of STDs?BB17 BB17
5. How does neanderthal man differ from the modern man in appearance?BB30 BB30
6. Write about copper releasing IUD’s?give example?
7. A person is infected by HIV.How will you diagnose for AIDS?BB23 BB29
8. Which type of reproduction is effective – Asexual or sexual and why?BB8 BB8
9. What is called ectopic pregnancy?Pg22 Pg22
10. What is capacitation?Pg21 Pg21
11. How is polyspermy avoided in humans?BB20 BB22
12. What is cryopreservation.What is its significance?Pg39 Ln3
13. What is called criss-cross inheritance?BB25 BB28
14. What are Holandric gene?Pg50 Pg51
15. State any three goals of the human genome project.BB20 BB25
16. Give reasons : Genetic code is universal?Pg72 Pg75
17. What is called connecting link?with example?Pg96 Pg98
18. How is milk converted in to curd?Explain the process of curd formation?BB8 BB8
19. What are transgenic animals?Give examples?Pg155 Pg166
20. What is soil permeability?Pg166 Pg180
21. Mention any two hotspots in India?Pg192 Pg208
22. What are the three levels of biodiversity?Pg182 Pg198
23. Which microorganisms causes cervical cancer?what are the symptoms?
24. Why are sex linked recessive characters more common in the male human beigns?
25. Differentiate Template strand and coding strand?
26. What are the cells involved innate immune system?
27. What is Acclimatisation?
28. What is co-extinction give example?
29. Write short note on Ecosan?
30. What are anaphylaxis?
31. Expand the acronyms a.HCG B.Hpl
32. What are Kala-azar?
33. Explain how ADA dificiency can be corrected?
34. List the advantages of biogas in rural areas?Ln9
35. What effect can fertilizer runoff have on an aquatic ecosystem?Ln13 BB14
36. What are the ways by which organisms respond to abiotic factors?Ln11 pg185
37. What is meant by biological products?Give examples?
38. Differentiate hibernation and aestivation?Ln11 Pg186

📢 More 12th Zoology Exam Resources:
📘 12th Zoology Three mark questions
📗 12th Zoology Five mark questions
📚 12th Zoology Model Question Papers

🎯 Why Focus on 2-Mark Questions in 12th Zoology?
Two-mark questions are a crucial part of the Zoology public exam, covering definitions, diagrams, short explanations, and key terms. Mastering these ensures full marks in this section.

📚 Chapter-wise 2-Mark Questions Covered:
🔹 Human Physiology – Circulatory System, Nervous System, Excretion
🔹 Genetics & Evolution – DNA Structure, Mendelian Inheritance, Evolution Theories
🔹 Biotechnology & Its Applications – Genetic Engineering, Cloning, DNA Fingerprinting
🔹 Ecology & Environment – Biodiversity, Conservation, Ecosystem Functions

📢 External References for Zoology Exam Preparation:
🔗 12th Zoology Textbook – Tnbooks
🔗 12th Zoology One marks short cuts

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