Cell organization

Learning outcomes

• State the necessity for cell specialisation in multicellular organisms as compared to unicellular organisms

• Describe cell specialisation in multicellular organisms

Unicellular organism

• Small and simple organisms

• Vital function within a single cell

• Depends on cellular component---organelles

• Does not have any organs or systems

• Example: Amoeba sp

Amoeba sp.

• Live in freshwater environments and soil water

• Have plasma membrane

• Changing shape when meets obstacles and responds to stimuli eg acidic water and bright light

Amoeba’s movement

• Extending pseudopodia

• Anchoring tips on the ground

• Flow of cytoplasm into the projected pseudopodia

• Pseudopodia also used for feeding

• Feeding by phagocytosis

Phagocytosis

• Extending its pseudopodia

• Pseudopodia enclose the food and packaged in a food vacuoles

• Food vacuoles fuses with lysosome

• Food is digested by enzymes

• Absorbed nutrients into the cytoplasm

Amoeba sp. Feed(makan)-phagocytosis

Respire(bernafas)-exchange of gases

Excrete(membuang)-waste subtances by Diffusion through plasmamembrane

Move(gerak)-Pseudopodia

Reproduce(membiak)-asexually by binary fission-when environment is favourable

Multicellular organism

Multicellular organism• More than one cell eg human

Male gamete + Female gamete

Zygote

2 identical cells

4 cells

8 cellsEmbryo

White blood cellNerve cellsRed blood cellsSperm cells