-
Mbsskl 2010
1
MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE
1) Figure 1 shows the structure of the plasma membrane:
Figure 1
(a) Label the diagram above: [8m]
A. B.
C. D.
E. F.
G. H.
(b) (i) Name the model of the plasma membrane in Figure 1.
[1m]
.
(ii) Based on b(i), explain the characteristics of the membrane
plasma. [3m]
..
..................
......................................................................................................................................................
(iii) State the arrangement of components A and B in Figure 1.
(2 marks)
F
H
D
A
B
C
E
G
-
Mbsskl 2010
2
..
(c) (i) State the functions of the plasma membrane. [2m]
..
(ii) State the function of D in the Figure 1. [1m]
..
(iii) State the characteristics of substances that can easily
pass through the phospholipid
bilayer. [1m]
..
(iv) Name the process by which these substances in c(iii) cross
the membrane. [1m]
.....
(v) Give 2 examples of such substances stated in c(iii).
[2m]
..
..
(d) (i) State the characteristics of substances that find
difficulty going through the
phospholipid bilayer. [1m]
..
(ii) Name 2 examples of such substances mentioned in d (i)
above. [2m]
..
-
Mbsskl 2010
3
(2) Figure 2 shows two solutions separated by a semi-permeable
membrane.
(a) (i) Complete the diagram to show what happens after 2 hours.
[2 m]
Semi-permeable
membrane
9.00 am 11.00 am
Note : = water molecule
= sucrose molecule
Figure2
(ii) Name the process that takes place in a(i): [1 m]
..
(iii) Define the process you have named in a(ii): [2m]
..
..
(iv) Name two processes in living organisms which use the
process in a(ii) [2m]
..
..
(b) How do the pore proteins carry out their functions? [1m]
..
(c) Compare how carrier proteins help in active transport and
passive transport.
Active transport: [4m]
A B A B
-
Mbsskl 2010
4
..
..
..
..
Passive transport: [4m]
..
..
..
..
(d) A red blood cell is placed into the following mediums. State
you observation. [3m]
(i) hypotonic solution:
.
(ii) isotonic solution:
.
(iii) hypertonic solution:
.
(e) What happens when a plant cell is placed into a : [3m]
(i) hypotonic solution?
.
(ii) isotonic solution?
.
(iii) hypertonic solution?
.
(iv) What happens when the plant cell in e(iii) is placed in
hypotonic solution? [3m]
.
(f) Why do we use salt to preserve fish? [3m]
.
-
Mbsskl 2010
5
( g) Figure 3 shows different modes of transport across the
plasma membrane.
Complete the figure: [6m]
Figure 3
MOVEMENT OF SUBSTANCES
ACROSS THE PLASMA MEMBRANE
PASSIVE TRANSPORT
Assisted by (D) ______________ proteins
A)
Osmosis B) C)
Assisted by
E) ________proteins
F) ________proteins
-
Mbsskl 2010
6
