ISC 2018 Biology Practical Question Paper for Class 12

About this paper

This is ISC Class 12 Biology Paper 2 (Practical), code 863B, from the 2018 board examination. The footer reads 1218-863B. It carries 30 marks, runs for three hours plus fifteen minutes of reading time, and has five questions, all to be answered. Question 1 is a floral study of specimen D-41, including the ovary in transverse section, the floral formula and the family. Question 2 tests enzyme D-42 on starch at 5 °C, 37 °C and 80 °C, with iodine added after 20 minutes. Question 3 is a safranin-stained longitudinal section of D-43, Question 4 is spotting of specimens A to E, and Question 5 is the project (10 marks) and the Biology Practical File (5 marks). This copy has the questions only.

Exam

ISC Class 12

Subject

Biology Practical

Year

2018

Paper code

863B

Maximum marks

30

Time allowed

3 hours + 15 min reading

Questions

5

Pages

4

Answers included

No, questions only

Paper pattern

• Question 1

  5 marks

  Floral study of specimen D-41: longitudinal section, androecium, ovary in transverse section, floral formula, floral diagram and family

• Question 2

  3 marks

  Enzyme D-42 acting on starch at 37 °C, 80 °C and 5 °C, including a boiled-enzyme control, tested with iodine

• Question 3

  2 marks

  Thin longitudinal section of specimen D-43, stained with safranin and mounted in glycerine

• Question 4

  5 marks

  Spotting: identify specimens A to E, with two reasons and a labelled diagram each; not more than three minutes a spot

• Question 5

  15 marks

  Project (10 marks) and Biology Practical File (5 marks), shown to the Visiting Examiner

Topics covered

• Floral morphology
• Androecium and placentation
• Floral formula and floral diagram
• Effect of temperature on enzyme activity
• Plant anatomy
• Specimen spotting

Questions from this paper

1. Describe the floral characteristics of specimen D-41 in semi-technical terms, and write its floral formula and floral diagram.
2. Name the family of D-41, give two characteristic features of that family, and name one economically important plant of the family with its full botanical name.
3. You are given a 5% solution of enzyme D-42, 1% starch, 1% NaCl and buffer of pH 6.8. What is the purpose of preheating the enzyme, and what is the end product of digestion by it?
4. Test tubes are held at 37 °C, 80 °C and 5 °C for 20 minutes and then treated with 1% iodine. What conclusions can be drawn?
5. Cut a thin longitudinal section of specimen D-43, stain it with safranin, and identify the specimen with two characteristic features.
6. Identify specimens A to E. Give two identifying characteristics of each and draw a labelled diagram. Do not spend more than three minutes on a spot.