Q1. (a)
(i)
How does water move into and out of cells?
Draw a ring around one answer.
breathing
osmosis
respiration
(1)
(ii)
Differences in the concentration of sugars in cells cause water to
move into or out of cells at different rates.
Diagram 2 shows three different cells, P, Q and R.
The information shows the percentage concentration of sugar
solution
in cells P, Q and R.
Water can move from cell to cell.
Into which cell, P, Q or R, will water move the fastest?
(1)
(Total 4 marks)
Q2. Some substances move through membranes.
A student set up an investigation.
The student:
•
tied a thin membrane across the end of a funnel
•
put concentrated sugar solution in the funnel
•
put the funnel in a beaker of water
•
measured the level of the solution in the funnel every 30 minutes.
The diagram shows the apparatus.
The graph shows the results.
(a)
After 3 hours, the level of the solution in the funnel is different from the
level at the start.
Explain why, as fully as you can.
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
(3)
(b)
The student repeated the investigation using dilute sugar solution instead
of concentrated sugar solution.
In what way would you expect the results using dilute sugar solution to be
different from the results using concentrated sugar solution?
Give the reason for your answer.
___________________________________________________________
___________________________________________________________
(2)
(Total 5 marks)
Q3.A student investigated the effect of different concentrations of a salt solution on the
mass of pieces of potato.
This is the method used.
1. Weigh five pieces of potato.
2. Put each piece of potato into a different concentration of salt solution.
3. Leave the potato pieces for 24 hours.
4. Remove each piece of potato, dry it and re-weigh it.
5. Calculate the change in mass of each piece of potato.
The table shows the results.
Concentration of salt
solution in arbitrary
units
(a)
Mass at start Final mass in
in g
g
Change in
mass in g
0
2.60
3.04
0.44
1
2.71
2.98
X
2
2.60
2.70
0.10
3
2.63
2.56
−0.07
4
2.46
2.22
−0.24
Calculate value X in the table.
___________________________________________________________
___________________________________________________________
X = ____________________ g
(1)
(b)
Two of the numbers for the change in mass have a negative value.
What do these negative values indicate?
___________________________________________________________
___________________________________________________________
(1)
(c)
Complete the graph.
•
Plot data from the table and your answer to part (a).
•
Draw a line of best fit.
(3)
(d)
Which concentration of salt solution would give no change in mass?
Use the graph.
Concentration = ____________________ arbitrary units
(1)
(e)
Explain why there would be no change in mass of a piece of potato at the
salt concentration you gave in part (d).
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
(3)
Q!. (a)
(i)
osmosis
apply list principle
1
(ii)
R
apply list principle
1
Q2.
(a)
water enters (funnel / sugar solution) or water diffuses in (to the funnel)
do not accept if diffusion of sugar
1
membrane partially / selectively / semi permeable or by osmosis
allow description
1
because concentration (of sugar) greater
inside funnel than outside / water / in beaker
assume ‘concentration’ refers to sugar unless
candidate indicates otherwise
the position of the solutions may be implied
1
(b)
(level / it) rises more slowly or levels out earlier or does not rise as much
accept inference of less steep gradient (of graph)
allow less / slower osmosis / diffusion / less water
passes through or less water enters funnel
allow water enters / passes through slower
1
less difference in concentration (between solution / funnel and water /
beaker)
accept due to lower diffusion / concentration
gradient / described
1
[5]
Q3.
(a)
0.27 (g)
1
(b)
potato lost mass
allow potato (cells) lost water
1
(c)
all 3 points plotted correctly
allow ecf from art (a)
allow 1 mark for 1 or 2 correct plots
2
suitable line of best fit
allow ecf from their plots
1
(d)
2.6 (arbitrary units)
allow answer from their line
1
(e)
same concentration as inside potato (cells)
1
(so) no (net) movement of water
allow description of this
1
by osmosis
1
[9]