biology activities for gcse - National STEM Centre

NUFFIELD BIOLOGY
CELLS DIVIDING
B60
To see what happens to the nuclei when cells divide you need to look at tissue
where the cells are dividing rapidly. A good choice is just behind the tip of a root.
To do
a Cut three 2-mm sections from the tip of
the root, such as from a germinating pea.
b Add the sections to a test-tube containing
0.5 cm3 dilute hydrochloric acid.
c Label your tube. Stand it in a water bath
at 60 °C for 5 minutes. This will help to
break down the cell walls.
d Remove the root sections from the acid.
Wash them on a watch glass with clean
water.
e Put each section on a different slide
labelled 1, 2, 3 to show where the section
was taken. Add a drop of stain.
f Break up the section with a needle.
g Cover with a cover slip. Then gently
squash the material with the slide
sandwiched between two layers of a paper
towel.
h Tap the cover slip lightly with the handle
of the needle to release the material.
i Examine the material through a
microscope.
place in
hydrochloric
acid and keep
in water bath
Wash your
hands after
3 handling plant
2 Section material
1
To record
Draw diagrams to show what you see in the root cells. Start with
region 3. If possible, draw a few typical cells from each region.
squash gently
Questions
1 Where are the chromosomes in a cell?
2 How does this process of nuclear division make sure that each cell in the body
has the same number of chromosomes in its nucleus?
© Nuffield Foundation 1996