Grade 9- Onion peel and cheek cell experiment

Name

Section

• A
• B
• C
• D
• E

Roll no

1. Given below is the diagram of a compound microscope. Study the diagram and answer the questions that follow. Identify the parts 1 to 5

• 1- Fine adjustment, 2- Coarse adjustment, 3- Objective lens (45X) , 4- Objective lens (10X), 5- Mirror
• 1- Coarse adjustment, 2- Fine adjustment, 3- Objective lens (10X) , 4- Objective lens (45X), 5- Mirror
• 1- Fine adjustment, 2- Coarse adjustment, 3- Objective lens (10X) , 4- Objective lens (45X), 5- Mirror
• 1- Coarse adjustment, 2- Fine adjustment, 3- Objective lens (45X) , 4- Objective lens (10X), 5- Mirror

1. To observe cells in an onion peel, we must prepare the slide by mounting on it _________.

• crushed pulp of onion
• dry scale leaf
• green leaf of onion
• thin layer of fleshy onion

2. Which one of the following is the correct sequence for preparing a mount of onion peel

• (i) take out onion peel (ii) keep the peel on the slide (iii) add a few drop of glycerine on it (iv) add few drops of safranin stain (v) cover it up with a coverslip
• (i) take out onion peel (ii) keep the peel in water in a petridish (iii) add a few drops of safranin stain and transfer to a slide (iv) add a drop of glycerine (v) cover it up with a coverslip
• (i) take out onion peel (ii) Keep it on a slide and add safranin stain (iii) transfer it to water in a petridish (iv) remove water and add glycerine (v) cover it up with a coverslip
• (i) take out onion peel (ii) cover it up with a coverslip (iii) on a petridish, add water to clean (iv) add a drop of glycerine (v) add a few drops of safranin stain

3. Given below are four operations for preparing a temporary mount of human cheek cells- (i) taking scraping from inner side of cheek and spreading it on a clean slide. (ii) putting a drop of glycerine on the material. (iii) adding 2-3 drops of methylene blue. (iv) rinsing the mouth with fresh water and disinfectant solution. The correct sequence of these operation is:

• i ii iii iv
• iv i iii ii
• iv i ii iii
• i iii ii iv

4. During observation of an onion peel/cheek cell, cells are first seen under

• high power
• low power
• medium power
• oil immersion

5. We generally mount the material on slide

• on left side.
• on right side.
• in the centre.
• both (a) and (b)

6. Coverslip is put on the mounted material on a slide very gently to

• avoid oozing of stain
• avoid oozing of glycerine
• avoid entry of air bubbles
• avoid the crushing of mounted materials