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Edexcel A-Level Biology AS 3.15 Core Practical 6 Root Tip Squash Mitosis Questions

Prepare a root-tip squash safely with acid, stain and microscope magnification, then count mitotic and total cells to determine the mitotic index.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
AS

Exam points

  • describe preparing root tips with acid, stain, squash technique and microscope observation
  • explain why staining, squashing and magnification make chromosomes and mitotic stages visible
  • calculate or compare mitotic index from mitotic and total cell counts

Edexcel A-Level Biology AS 3.15 Core Practical 6 Root Tip Squash Mitosis Questions question 1

[Maximum number: 8]

The flow chart shows how garlic root tips can be treated to observe mitosis in the root cells.

Figure for Question Edexcel A-Level Biology AS 3.15 Core Practical 6 Root Tip Squash Mitosis Questions question 1 — Edexcel A-Level Biology AS

Question (a)

(a)

Give one reason why each of the following steps was taken.
(3)

Step 2

Step 4

Step 5

[ 3 ]

Question (b)

(b)

Describe how the procedure shown in the flow chart could be used to investigate the effect of pH on the mitotic index.

[ 5 ]
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