Answer Key
Activity 1
A.
Carbohydrate E. Carrier protein
B Glycoprotein F.
Channel protein
C phospholipids bilayer G. Glycolipid
D Cytoplasm H. Cholesterol
Activity 2
A.
Hypotonic
B.
Isotonic
C.
Hypertonic
Activity 3
- Lipid 6. Carrier protein
- Semi-permeable 7. Active transport
- Energy 8. Flaccid
- Facilitated diffusion 9. Turgid
- Osmosis 10. Flaccid
Assessment
A.
Objective ( 10 marks)
1. A 6. C
2. B 7. A
3. A 8. B
4. C 9. C
5. C 10. D
B.
Structure ( 8 marks)
(a) i )
Cell Q [1]
ii) Cell
P [1]
(b) The cell is said to be plasmolysed [2]
(c) The higher concentration of solute in solution
(hypertonic solution)
causes water
to leave the cell by osmosis.
Both the vacuole
and cytoplasm shrink and
the plasma
membrane pull away from the cell wall.
The cell becomes flaccid. [3]
(d) By
placing it in distilled water. [1]
C) . Essay (20
marks)
1.(a)
Simple diffusion- Movement
of molecules in gas or liquid from a
region
of higher concentration to a region
of lower
concentration [2]
Facilitated
diffusion-
Movement of big molecules along a concentration
gradient
with the help of protein carriers
across
the plasma membrane. [3]
Osmosis - Movement of water molecules across
a semipermeable membrane.
from a region of lower concentration
to
a
region of higher concentration
[3]
Active transport- Movement of particles across plasma
membrane
against the concentration gradient with
the help
of protein
carriers and the presence of energy
from ATP.
[4]
(b)
Active
transport
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Needs energy
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Does not need energy
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Movement of molecules or ions against
a concentration gradient
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Takes place through the plasma membrane of a
living cell
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Needs protein carriers
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