Save
...
biology
PAGs
PAG 8: osmosis
Save
Share
Learn
Content
Leaderboard
Learn
Created by
lucy dock
Visit profile
Cards (7)
osmosis
the
net movement
of
water particles
from a
higher water potential
to a
lower water potential
through a
partially permeable membrane
Describe how you would carry out an investigation into osmosis using potato tissue
cut
identical
potato cylinders using a
cork borer
measure and record the
length
and
mass
of cylinders using a
ruler
and
balance
add each cylinder to one of three solutions:
1M sugar solution
,
0.5M sugar solution
and
distilled water
leave cylinders in
tubes overnight
remove cylinders from tubes and
blot
them using
paper towels
record
length
and
mass
of each cylinder
draw graph of change in mass in
grams
(y axis) against
concentration
of
solution
in mol dm^
-3
(
x axis
)
why is it to use a cork borer to cut the cylinders?
results in
equal sized samples
so changes in
length
and
mass
can be
compared easily
what is it necessary to blot the cylinders with paper after removing them?
each cylinder may have a
different amount
of
water
on its
surface
, so
masses
may
vary.
blotting
cylinders allows
masses
to be
comparable
what safety precautions should be taken with this experiment?
handle cork borer
and
scalpel
with
care
how can the water potential of the plant cells be found?
plot a graph of
change
in
mass
against
concentration
find the
x-intercept
, which is the
concentration
of
solution
that is
isotonic
to the plants
state a source of error in this practical
plant
tissue
taken from
different parts
of the
plant
may have different
water potentials
