1. PROTIST
KINGDOM

2. PROTIST KINGDOM
 includes unicellular organisms e.g.
Animal-like
organisms - Amoeba
Algae - Chlorella

3. Chlorella: a unicellular green
alga
lives in stagnant water
Chlorella cell
dividing.

4. Chlorella structure
nucleus cell wall
nucleolus cell membrane
cytoplasm
chloroplast
(cup-shaped)
Pyrenoid
(a collection of
starch grains)

5. Chlorella feeds:
 autotrophically
 builds the food itself by
photosynthesis
 uses:
 carbon dioxide
to make sugar
 water

6. Humans add Chlorella to their
food
 rich in proteins

7. Amoeba
 a unicellular animal-like organism
 lives in stagnant water
Give two functions
of pseudopodia
(‘false feet’). Pseudopodia

8. Functions of pseudopodia:
1. moving
2. feeding

9. Amoeba

10. Amoeba
PART LABEL FUNCTION
A endoplasm it houses all the cells organelles
B ectoplasm since in a gel state it protects the cell
C contractile vacuole it expels excess water from the cell
D pseudopodium plays a role in locomotion and food capture
controls movement of substances into and out of the
E cell membrane
cell
F food vacuole digests engulfed food
G nucleus controls activities of the cell

11. Holozoic nutrition in Amoeba
1 2 3
Amoeba Pseudopodia The food is enclosed
senses food. surround the food. in a food vacuole
(food + water).
5 6
4
Enzymes from the Food is digested and
cytoplasm are soluble materials are Undigested
secreted into the absorbed and waste is
food vacuole. assimilated (used up). expelled.

12. Amoeba reproduces asexually
by splitting into two:
 binary fission

13. Osmoregulation in Amoeba
 Osmoregulation:
 controlling the amount of water in the
organism
 is carried out by the contractile vacuole
Contractile vacuole
pumps out water.

14. Osmoregulation in Amoeba
1 Water enters the Amoeba by
osmosis and collects in the
contractile vacuole.
2
The contractile
vacuole swells up. 4 The process starts all
over again.
3
The contractile vacuole
bursts to release the water.

15. Paramecium: two fixed
contractile vacuoles
Contractile vacuoles

16. Marine amoebae do not
possess a contractile vacuole.
Explain.
Marine Amoeba Freshwater Amoeba
Marine amoeba: same concentration as sea
water. No excess water enters into them.

17. Question: MAY, 2010
Give a biological explanation for the following
statement:
Single-celled organisms such as the
Paramecium need a contractile vacuole. (5)
Contractile vacuole removes
excess water to avoid bursting of
the organism.

18. Amoeba does not need a
specialised respiratory surface.
Why?
 Amoeba is small, and so it has a large
surface area to volume ratio
 this means that oxygen can diffuse from all
over the cell membrane and reach all parts
of the amoeba quickly

19. Gaseous exchange in Amoeba
occurs by:
 diffusion across the cell membrane
Why does O2
keep on entering?
Why does CO2
move out all the
Gases move down their time?
concentration gradient.