Mitosis in Root Tip

Question 1

what was the purpose of this experiment?

Answer 1

to observe cells from a root tip in different stages of interphase and mitosis

Question 2

where does mitosis typically occur in plants? what are these areas responsible for?

Answer 2

• in apical meristems –> responsible for the lengthening of roots an shoots
• and in lateral meristems –> responsible for increasing girth

Question 3

why is a root tip (apical meristem) convenient tissue to examine?

Answer 3

because it lacks chloroplasts, which in shoot and leaf material interfere optically with the observation of chromosomes

Question 4

what are the 4 zones of a root tip? where does mitotic cell division occur?

Answer 4

Zone A –> Root Cap
Zone B –> Zone of cell Division (apical meristem)
Zone C –> Zone of Elongation
Zone D –> Zone of Cell Differentiation

mitotic division occurs in zone B

Question 5

what kind of tissues are used to study mitosis in animals?

Answer 5

embryonic tissues (especially fishes and amphibians) and human white blood cells

Question 6

what kind of stain is used in this lab? why do we use stain? what colours should we see?

Answer 6

• aceto orcein
• use stain to make the chromosomes more visible
• it stains the chromosomes darkly and other cellular components lightly
• nuclear material should be deep purple
• cytoplasm should be pale pink

Question 7

what did we use to hydrolyze the root tips? why is this step necessary?

Answer 7

use 1 M of HCl
-necessary to hydrolyze the molecules that hold cells together so that the cells can be squashed into a single monolayer and can be examined through a microscope

Question 8

what was the specimen used in this experiment, including scientific name?

Answer 8

fava bean –> Vicia faba

Question 9

how many chromosomes does a fava bean have?

how many chromosomes does a fava bean have in prophase of mitosis?

Answer 9

• has 12 (6 from mom, and 6 from dad)

- still has only 12, but they are now replicated, meaning they are each made of 2 chromatids

Question 10

if a particular cell in a fava bean root tip has half as much DNA as other nearby cell, what phase is this cell in?

Answer 10

• the cell would be in G1 of interphase

- meaning it recently split during telophase and has become 2 daughter cells.