Two examples of permeable membranes are the phospholipid bilayer cell membrane and the inner membrane of an egg.
Here's a more detailed explanation:
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Phospholipid Bilayer Cell Membrane: This membrane surrounds every cell in our bodies. It's selectively permeable, meaning it allows some substances to pass through easily, others with difficulty, and some not at all. This selectivity is crucial for maintaining the cell's internal environment and carrying out essential functions. The phospholipid bilayer's structure, with hydrophobic tails facing inwards and hydrophilic heads facing outwards, dictates which molecules can pass through. Small, nonpolar molecules can generally pass through easily, while large, polar molecules and ions require the assistance of transport proteins.
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Inner Membranes of an Egg: These membranes are also selectively permeable. They protect the developing embryo and regulate the passage of nutrients and waste products. The specific permeability characteristics vary depending on the stage of development and the needs of the embryo. Similar to cell membranes, these inner membranes play a vital role in maintaining the appropriate environment for growth and development.
In essence, permeable membranes are biological barriers that control the movement of substances, ensuring that cells and organisms can maintain homeostasis and carry out their functions effectively. The cell membrane acts as a gatekeeper for cellular processes, whereas the egg membranes support embryonic development.
