Onion and Cheek cells

Question 1

What are the 4 steps to preapring an onion cell slide?

Answer 1

1.) Cut a thin layer of onion epidermis using scalpel.
2.) Place onion on slide using forecps.
3.) Add 2 drops of iodine
4.) Place coverslip at an angle

Question 2

Why do you use iodine solution to stain onion cells?

Answer 2

• Onion cells = transparent
• Onion cells = starch
• Iodine turns blue- black in the presence of starch.
• Make it more clear

Question 2

Why do you use forceps to move the onion epidermis to the glass slide?

Answer 2

• To ensure no germs from your hand are transferred to the slide.
• This would intefer with results*

Question 3

What is a “coverslip”?

Answer 3

• A coverslip is a thin sheet of glass to put on top of the specimen.

Question 4

Why is the coverslip placed at an angle?

Answer 4

• The coverslip is placed at an angle to avoid any air bubbles forming.
  This would intefer with your results

Question 5

What are the 6 steps to preparing a cheek cell slide?

Answer 5

1.) Place cotton bud onto side of cheek.
2.) Move back and forth.
3.) Spread over middle of slide in zig - zag motion
4.) Add a few drops of methylene blue.
5.) Place the coverslip at an angle.
6.) Place cotton bud in disinfectant.

Question 6

Why is the cotton bud placed in disinfectant after use?

Answer 6

• To avoid the spread of microbes.

Question 7

Which dye do we use when we view onion cells under the microscope?

Answer 7

• Iodine solution.

Question 8

Which dye do we use when we view human cheek cells under the microscope?

Answer 8

• Methylene blue.

Question 9

Why do we only use a thin layer of onion?

Answer 9

• To view the cells in more detail.

Question 10

Why are scale bars useful?

Answer 10

• Scale bars are useful because it shows the actual size of an object even if the size has been altered by printer.