Download Osmosis

MOVEMENT OF SUBSTANCES
Student Name ______________________________
1.
1. What process is responsible for the uptake of minerals in a plant? ________________________
2. Name the process responsible for the entry of water into a plant. ________________________
3. What is osmosis? ___________________________________________________________________
4. Water enters the outermost cells of the root by osmosis. What does this tell you about the cell sap of these
outermost cells? ________________________________________________
5. Describe how minerals such as nitrates enter the root of a plant from the soil. _________________________
6. Osmosis has been described as a special case of diffusion. Explain why._______________________________
_________________________________________________________________________________________
7. What is meant by osmoregulation? ____________________________________________________________
_________________________________________________________________________________________
8. Where precisely does water enter a plant? ______________________________________________
9. In which tissue does water ascend through the plant? ________________________
2. Explain each of these terms:
1 Diffusion ___________________________________________________________
3 Visking tubing ___________________________________________________________
4 Passive process ___________________________________________________________
5 Semi-permeable ___________________________________________________________
6 Osmoregulation ___________________________________________________________
7 Turgid ___________________________________________________________
8 Plasmolysed ___________________________________________________________
9 Food preservation ___________________________________________________________
10 Dehydrated ___________________________________________________________
11 Active transport ___________________________________________________________
3. Complete the following:
Molecules move from a _________________ concentration to a _________________ concentration by
_________________. Osmosis is the movement of _________________ molecules from an area where they are
in a _________________ concentration to where they are in a _________________ concentration, through a
____________ –permeable membrane. When plant cells take up water by osmosis they become
_________________ .These cells help _________________ parts of a plant like the stem. If plant cells lose water,
the stem loses support and it_________________. If plant cells lose a lot of water, the cell _________________
peels away from the cell _________________ and the cell is said to be _________________
4. The diagram shows the apparatus for an experiment
using Visking tubing. The tubing is flexible and
allows very small molecules to pass through it but
not larger ones.
(a) Make a similar drawing to show the
appearance of the tubing after one hour.
(b) Explain how this change occurred. _______________________________________________
(c) What is the name of the process that causes this change? ______________________________
(d) Explain why half a cucumber becomes soft if left lying on a kitchen shelf for a few days, but becomes
turgid again if its cut end is placed in water.
___________________________________________________________________________
__________________________________________________________________________
5. (a) Red blood cells have a 1% salt concentration inside them. What would happen to the red blood cells if
they were placed in a beaker containing the following solution:
(i) pure water _______________________________________________
(ii) a 1% salt solution _______________________________________________
(iii) a 5% salt solution? _______________________________________________
(b) A plant cell also has a salt concentration of 1% in its cytoplasm and central vacuole. Say what
differences there would be when these cells are placed in each of the three solutions mentioned in (a).
(i) pure water _______________________________________________
(ii) a 1% salt solution _______________________________________________
(iii) a 5% salt solution? _______________________________________________
(c) An amoeba living in a freshwater pond contains a contractile vacuole.
State the function of this structure _______________________________________________
Explain why its presence is necessary _______________________________________________
Why does an amoeba living in seawater not possess a contractile vacuole?
__________________________________________________________________________
6. Three strips of plant epidermal cells were placed on
microscope slides. Each was covered by one drop
of a solution, as shown in the table.
STRIP 1 STRISTRIP 3
The diagrams below show the appearance of some
of the cells after one hour.
Two of the strips had cells as shown in diagram A.
One strip had cells as shown in diagram B.
(a) (i) Which one of the strips (1, 2 or 3) would have cells
that look like Diagram B?_________________________
(ii) Explain what happens to a cell to make it look like
Diagram B.____________________________________
(b) Which one of the following would be found at the position labelled X in Diagram B?
Water alone, Sugar solution Cell sap, Air, Cytoplasm ________________________________
(c) What would happen to a leaf if most of its cells became like Diagram B? _________________________