CBSE Board Paper Solution-2020

Class : XII Subject : Biology Set : 1 Code No : 57/3/1 Time allowed : 3 hours Maximum Marks : 80

General Instructions:

Read the following instructions very carefully and strictly follow them:

(i) Question paper comprises five sections - A, B, C, D and E.

1. There are 27 questions in the question paper. All questions are compulsory.
2. Section A – Questions no. 1 to 5 are multiple choice questions, carrying 1 mark each.
3. Section B – Questions no. 6 to 12 are short- answer questions type-I, carrying 2 marks each.
4. Section C – Questions no. 13 to 21 are short- answer questions type-II, carrying 3 marks each.
5. Section D – Questions no. 22 to 24 are short- answer questions type-III, carrying 3 marks each.
6. Section E – Questions no 25 to 27 are long- answer questions, carrying 5 marks each.
7. Answers should be brief and to the point.

1. There is no overall choice in the question paper. However, an internal choice has been provided in two questions of 1 mark, one question of 2 marks, two questions of 3 marks and three questions of 5 marks. Only one of the choices in

such questions have to be attempted.

1. The diagrams drawn should be neat, proportionate and properly labelled, wherever necessary.
2. In addition to this, separate instructions are given with each section and question, wherever necessary.

SECTION A

Note:- Choose the correct option from the choices given in each of the following questions :

1. Introduction of an alien DNA into a plant host cell is achieved by making them
2. Competent with bivalent ions
3. Using microinjections
4. Using gene gun
5. Using lysozymes and chitinase

[1]

Answer:

1. Using gene gun