CP3-Mitosis

Question 1

Objectives-Observe Mitosis in root tips

Root tip squash

Answer 1

Objectives:

• know how to prepare a temporary slide of a root tip to observe mitosis
• recognise the stages of mitosis in dividing cells

Question 2

Risks?

Answer 2

• glassware can shatter
• acetic orcein is corrosive and causes burns
• wear goggles and gloves
• wash away spills from skin as soon as possible for 10 mins

Question 3

Method?

Answer 3

• submerge roots of plant in hydrochloride acid for 5 minutes, remove and rinse with distilled water
• cut off the end of the roots, the meristem section only, and place the ends in a vial of acetic orcein dye for 5 minutes
• place roots on microscope slide and macerate gently using needles to speed the cells out in a thin layer
• cover with the coverslip and SQUASH gently
• examine under low power to identify area of dividing cells (meristem)
• examine under high power to see cells in stages of mitosis

Question 4

Why do you add hydrochloride acid and heat in a water bath?

Answer 4

• heating will break up the tissues into individual cells

- hydrochloride acid will break down the calcium pectate which holds the cellulose cell walls of plant cells together