CBSE Class 12 Biology Question Paper 2019 (Set-3)
This is the CBSE Class 12 Biology Previous Year Question Paper from the 2019 All India Main Exams, Set 3. The question paper consists of 27 questions divided into four sections: Section A (questions 1-5) with one-mark very short answer questions, Section B (questions 6-12) with two-mark short answer type I questions, Section C (questions 13-24) with three-mark short answer type II questions, and Section D (questions 25-27) with five-mark long answer questions. While there is no overall choice, internal choices are provided in some questions across all sections. Solving this board question paper is crucial for students to understand the exam pattern, question types, and marking scheme, thereby enhancing their preparation and performance in the upcoming CBSE board exams.
Quick info
| Board | CBSE |
|---|---|
| Class | 12 |
| Subject | Biology |
| Session | 2019 |
| Language | English |
| Type | Previous Year Question Paper |
| Exam type | Board Exam |
Paper pattern
The question paper has 27 questions across four sections (A, B, C, D) with varying marks (1, 2, 3, 5). Internal choices are available in specific questions.
Topics covered
Paper topics
- DNA Transcription Unit
- Genus Glomus
- Mycorrhiza
- Angiospermic Plant Chromosomes
- Pollen Grain Viability
- Tapetum
- Biotechnological Diagnostic Techniques
Important topics
- Transcription Unit
- Mycorrhizal Symbiosis
- Chromosome Number in Angiosperms
- Pollen Viability Factors
- Biotechnology in Disease Diagnosis
PDF preview
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Question paper text
Biology Question Paper 2019 (Set-3)
General Instructions:
- There are total 27 questions and four sections in the question paper. All questions are compulsory.
- Section A contains questions number 1 to 5, very short answer type questions of one mark each.
- Section B contains questions number 6 to 12, short answer type I questions of two marks each.
- Section C contains questions number 13 to 24, short answer type II questions of three marks each.
- Section D contains question number 25 to 27, long answer type questions of five marks each.
- There is no overall choice in the question paper, however, an internal choice is
provided in two questions of one mark, two questions of two marks, four questions of three marks and all the three questions of five marks. In these questions, an examinee is to attempt any one of the two given alternatives.
- Wherever necessary, the diagram drawn should be neat and properly labelled.
Question 1
What do 'X' and 'Y' represent in the transcription unit of the DNA molecule shown? 3" 5"
SOLUTION:
- Template strand
- Terminator
Question 2
How are the members of genus Glomus useful to organic farmers?
SOLUTION:
Glomus belongs to a group of fungi which form mycorrhiza. They form symbiotic association with plants and absorb phosphorous from soil and pass it to the plants. Such associations help the plants in other ways as well - resistance to root borne pathogens, tolerance to salinity and drought. This also results in the overall increase in plant growth and development.
Question 3
The diploid number of chromosomes in an angiospermic plant is 16. What will be the number of chromosomes in its endosperm and antipodal cells?
OR
State the reason why pollen grains lose their viability when the tapetum in the anther is malfunctioning.
SOLUTION:
The endosperm is triploid in nature which means it will have 48 chromosomes. The antipodal cells are haploid in nature which means, they will have 8 chromosomes.
OR
Tapetum is the innermost wall layer which provides nourishment to the developing pollen grains. If the tapetum is malfuntioned, proper nourishment to the pollen grains would not be provided and thus would eventually lose their vaiblity.
Question 4
Biotechnological techniques can help to diagnose the pathogen much before the symptoms of the disease appear in the patient. Suggest any two such techniques. OR
Frequently asked questions
What is this document?
This is the official CBSE Class 12 Biology Previous Year Question Paper from the 2019 Main Exams (Set 3).
What is the structure of the paper?
It contains 27 questions divided into four sections: Section A (1-mark), Section B (2-marks), Section C (3-marks), and Section D (5-marks).
Are there choices available in the questions?
Yes, there are internal choices provided in some questions within each section, allowing you to attempt one of the given alternatives.
How does solving this paper help?
Solving this previous year question paper helps students understand the CBSE exam pattern, question difficulty, and marking scheme, improving their preparation and confidence.
What is the total duration and maximum marks?
The provided text mentions the number of questions and marks per section but not the total duration or maximum marks for the paper.
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