Page 11 - Cell biology PDG 2024
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Figure 5: propagation of action potential
2) Cell wall
• A cell wall is a membrane surrounding some types of cells, just
outside the cell membrane.
• It provides the cell with both structural support and protection, and
also has a filtering property.
• Cell walls are present in most prokaryotes, in algae, fungi and
eukaryotes including plants but are absent in animals.
• In a plant cell, the cell wall is made up of cellulose, hemicellulose,
and proteins while in a fungal cell, it is composed of chitin.
• Its major function is to prevent over-expansion of the cell when
water enters.
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