CBSE 2018 Biology Solved Paper for Class 12

About this paper

This is a CBSE Class 12 Biology paper (Set 1) from the 2018 board examination, with an answer written under every question. It has 26 questions in five sections, A to E, from short one-line questions to five-mark long answers; marks and time are not printed on this copy. Section D is a value-based question on worsening city air quality, asking what you would organise as captain of the school Eco-club. Internal choices appear in one Section B question, one Section C question and all three Section E questions, and answers are given for both alternatives. Questions cover the Arcata Marsh waste-water project, sex determination in birds, RNA interference in tobacco, DNA fingerprinting and the menstrual cycle.

Exam

CBSE Class 12

Subject

Biology

Year

2018

Questions

26

Pages

15

Answers included

Yes

Paper pattern

• Section A

  Questions 1–5, very short answers

• Section B

  Questions 6–10, short answers; internal choice in Question 10

• Section C

  Questions 11–22, short answers; internal choice in Question 13

• Section D

  Question 23, value-based question on air pollution

• Section E

  Questions 24–26, long answers, each with an internal choice

Topics covered

• Reproduction in flowering plants
• Human reproduction
• Principles of inheritance and variation
• Molecular basis of inheritance
• Evolution
• Human health and disease
• Strategies for enhancement in food production
• Microbes in human welfare
• Biotechnology principles and applications
• Organisms and populations
• Biodiversity and conservation
• Environmental issues

Questions from this paper

1. Write the dual purpose served by deoxyribonucleoside triphosphates in polymerisation.
2. How did the citizen group Friends of Arcata Marsh in Arcata, California, USA, help to improve the water quality of the marshland using integrated waste water treatment? Explain in four steps.
3. Explain the mechanism of sex determination in birds. How does it differ from that in human beings?
4. Expand VNTR and describe its role in DNA fingerprinting.
5. If 8 individuals in a population of 80 butterflies die in a week, calculate the death rate of the population during that period.
6. Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy.