Thursday, March 19, 2009

Biology ~ The cell organization in unicellular

In this subtopic, we will learn more on:
- The living process in amoeba and paramecium
- The organization in multicellular organism in the form of tissue, organ, system and organism

ORGANISM
-Living thing that capable of undergo vital function & living process.

1-Unicellular organism
~ One single cell only
Eg: Paramecium, bacteria, Amoeba

2-Multicellular organism
~ More than one cell
Eg: plant & animal


Unicellular organism – Amoeba sp
~>Characteristic
-Enclosed by plasma membrane
-Changes shape as respond towards stimuli (eg: food)
-Ectoplasm: gel-like outer part of cytoplasm
-Endoplasm: inner cytoplasm
~>Habitat
-Freshwater, ponds, damp soil
-Free living, some parasitic
~>Respiration
-Exchange of O2 and CO2 by simple diffusion through plasma membrane
~>Excretion
-Waste product removed from cell by simple diffusion
-Osmoregulation by contractile vacuole (removal of excess water)
~>Find more on: Locomotion, Feeding and Reproduction


- The video on Amoeba locomotion -
video

- The video on Amoeba feeding -
video



Multicellular organism
~>Multicellular organism is organism that consist of more than one cell
Example: plant, animal

~In multicellular organism, life begin from a single cell that known as zygote.
-Example: human
~The cell grow, change shape and differentiate to carry out specific function.
-Means that a single cell do not have to carry out all vital process such in a single Amoeba to sustain life.

~Cells of multicellular organism differentiate and undergo specialisation to perform task efficiently.
-Example: - Red blood cell for transport
- White blood cell for defence
- Nerve cell for impulse transmission



Structure question











Paramecium is a freshwater protozoan. Answer the following questions.

(a)How many contractile vacuoles present in the paramecium? (1 marks)
(b) (4 marks)
i- Water is always diffusing into the paramecium. Why is this so?
ii- Name the process by which the water enters the paramecium.
iii- Name the substance that is eliminated when the contractile vacuole contracts.
(c)What would be happen to the paramecium of the contractile vacuole stops contracting? (1 marks)
(d)Describe how the paramecium gets its
i- Oxygen supply
ii- Food (4 marks)

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