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CBSE 12th Biology Sample Paper 2021 Released (With Answers & Marking Scheme) - Download PDF

Mayank Uttam

CBSE Class 12th Biology Sample Paper 2021 (PDF) has been released by CBSE along with answers and new CBSE Marking Scheme. With this article, students can download these resources in PDF format. With these papers, students can easily understand the level of questions expected in the papers along with the exam pattern of CBSE Class 12 Biology board exam 2021.

CBSE Class 12 Sample Paper 2021 Released Along CBSE Class 12 Marking Scheme - Download PDF Now!

CBSE 12th Biology Sample Paper 2021 Released (With Answers & CBE Marking Scheme)

Sample Question Paper 2020-21

Class XII

Biology (044) Theory

Time: 3 Hours,  Maximum Marks: 70

General Instructions:

(i) All questions are compulsory.

(ii) The question paper has four sections: Section A, Section B, Section C and Section D. There are 33 questions in the question paper.

(iii) Section–A has 14 questions of 1 mark each and 02 case-based questions. Section–B has 9 questions of 2 marks each. Section–C has 5 questions of 3 marks each and Section–D has 3 questions of 5 marks each.

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(iv) There  is  no  overall  choice.  However,  internal  choices  have  been  provided  in  some questions. A student has to attempt only one of the alternatives in such questions. 

(v) Wherever necessary, neat and properly labeled diagrams should be drawn.

SECTION A

1. Why does endosperm development precedes embryo development?

2. How many meiotic divisions are required to produce 76 seeds in a Guava fruit?    

3. How does pollination take place in water hyacinth and water lily?    

4. Name the glands that contribute to human seminal plasma.    

5. A snapdragon plant with violet flowers was crossed with another such plant with white flowers. The F1 progeny obtained had pink flowers. Explain, in brief, the inheritance pattern seen in offsprings of F1 generation?    

6. Differentiate between aneuploidy and polyploidy.    

7. Predict the effect if, the codon UAU coding for an amino acid at the 25th position of a polypeptide of 50 amino acids, is mutated to UAA.    

8. Differentiate between pro-insulin and mature insulin.    

9. Name the commonly used vector for cloning genes into higher organisms.    

10. Which of the three forests- Temperate, Mangroves and Tropical Evergreen is more vulnerable to invasion by outside animals and plants?    

11. Assertion: Primary transcripts in eukaryotes are nonfunctional.

Reason: Methyl guanosine triphosphate is attached to 5’ – end of hnRNA.

a. Both assertion and reason are true, and reason is the correct explanation of assertion.

b. Both  assertion  and  reason  are  true,  but  reason  is  not  the  correct explanation of assertion.

c. Assertion is true but reason is false. d.   Both assertion and reason are false.

OR

Assertion: An organism with lethal mutation may not even develop beyond the zygote stage.

Reason: All types of gene mutations are lethal.

a. Both  assertion  and  reason  are  true,  and  the  reason  is  the  correct explanation of the assertion.

b. Both  assertion  and  reason  are  true,  but  the  reason  is  not  the  correct explanation of the assertion.

c. Assertion is true but reason is false. d.   Both assertion and reason are false    

12. Assertion: E. coli having pBR322 with DNA insert at BamHI site cannot grow in medium containing tetracycline.

Reason: Recognition site for Bam HI is present in tetR region of pBR322.

a. Both assertion and reason are true, and the reason is the correct explanation of the assertion.

b. Both assertion and reason  are  true,  but  the  reason  is  not  the  correct explanation of the assertion.

c. Assertion is true but reason is false. 

d. Both assertion and reason are false

13. Assertion: A community with more species is more stable than that with less species.

Reason: More the number of species, lesser the variation in the total biomass production year after year.

a. Both  assertion  and  reason  are  true,  and  the  reason  is  the  correct explanation of the assertion.

b. Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

c. Assertion is true but reason is false. d.   Both assertion and reason are false

14. Assertion: In Ophrys one petal of the flower bears an uncanny resemblance to the female bee.

Reason: Two  closely  related  species  competing  for  the  same  resource  can coexist simultaneously.

a. Both  assertion  and  reason  are  true,  and  the  reason  is  the  correct explanation of the assertion.

b. Both  assertion  and  reason  are  true,  but  the  reason  is  not  the  correct explanation of the assertion.

c. Assertion is true but reason is false. d.   Both assertion and reason are false

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For all the questions, download PDF of CBSE Class 12 Biology Sample Paper 2021 and for answers, download CBSE Class 12 Biology MArking Scheme 2021 from the links given below

CBSE Class 12 Biology Sample Paper 2021 (PDF)

CBSE Class 12 Biology Marking Scheme 2021 or Answers of CBSE Class 12 Biology Sample Paper 2021 (PDF)

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