Observing mitosis Flashcards
1
Q
What is a general summary of the investigation?`
A
Chromosomes are stained blue using orcein ethanoic stain so mitosis can be observed
2
Q
Equipment needed.
A
- garlic roots
- sharp knife
- 1M hydrochloric acid (1M means moles per litre basically it just indicates a specific concentration0
- ethanoic acid
- orcein ethanoic stain
- ice-cold distilled water
- water bath at 60 degrees celcius
3
Q
Method.
A
- place test tube of 2cm3 1M hydrochloric acid (HCL)
- cut off 1-2cm of root tip from garlic
- put in a test tuse containing 2cm3 of acetic alcohol for at least 12 mins
- remove and place in another test tube containing 5cm3 of ice cold distilled water
- leave fr 4-5 minutes then remove and dry
- place tips into heated HCL for 5 mins
- repeat 3-6 again
- transfer tip to microscope slide and cut 4-5mm from the growing tip
- gently macerate (break up) the tip with mounted needle
- add one small drop of orcein ethanoic stain and leave for 2 mins
- add coverslip and blot with filter paper
- view under microscope and identify the stages of mitosis
4
Q
What volume of hydrochloric acid is needed?
A
2cm3
5
Q
What volume of acetic acid is needed?
A
2cm3
6
Q
What volume of distilled water is needed?
A
5cm3
7
Q
How long should the sample be before the second chop?
A
1-2cm
8
Q
How much of the root tip is actually used under the microscope?
A
4-5mm
9
Q
How long should the root tip be in the acetic alcohol for?
A
at least 12 minutes
10
Q
How long should the root tip be in the distilled water for?
A
4-5 mins
11
Q
How long should the root tips be in the hydrochloric acid for and at which temperature?
A
5 mins at 60 degrees
12
Q
What is the name of the stain?
A
orcein ethanoic stain
13
Q
Possible evaluation issues?
A
- resolution of microscope
- human error in counting number of cells
- enough time in solutions
