Endocytosis and exocytosis
Osmosis from Elsevier・2 minutes read
Cells utilize various mechanisms such as diffusion, membrane-bound proteins, endocytosis, and exocytosis to transport materials across their cell membrane, with different molecules crossing at different rates depending on their properties. Transport proteins like aquaporins and glucose transporters play a crucial role in aiding the passage of molecules, while endocytosis and exocytosis involve specific processes and require ATP for engulfing and releasing materials, respectively.
Insights
- Different molecules cross cell membranes at varying speeds and through distinct mechanisms: small nonpolar molecules diffuse rapidly, while large polar molecules and charged ions necessitate transport proteins for passage.
- Endocytosis and exocytosis are intricate processes that involve the engulfing and release of materials by cells, respectively, with the former requiring ATP for internal digestion and the latter utilizing motor proteins for vesicle transport.
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Recent questions
How do cells transport materials?
Cells transport materials through diffusion, membrane-bound proteins, endocytosis, and exocytosis.
What are the categories of molecules crossing cell membranes?
Molecules crossing cell membranes are categorized as small nonpolar, small polar, large nonpolar, large polar, and charged ions.
What role do transport proteins play in cell membrane passage?
Transport proteins like aquaporins and glucose transporters aid in the passage of molecules through the cell membrane.
What is involved in endocytosis?
Endocytosis involves phagocytosis, pinocytosis, and receptor-mediated endocytosis, requiring ATP for engulfing extracellular material and digesting it within lysosomes.
How does exocytosis occur in cells?
Exocytosis begins in the Golgi apparatus, packaging proteins and hormones into secretory vesicles that move towards the cell membrane, fuse with it, and release their contents into the extracellular space with the help of motor proteins and ATP.
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Summary
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Cell Membrane Transport Mechanisms: A Summary
- Cells transport material across their cell membrane using diffusion, membrane-bound proteins, endocytosis, and exocytosis.
- Five categories of molecules attempt to cross the cell membrane: small nonpolar molecules like oxygen diffuse rapidly, small polar molecules like water cross slowly, large nonpolar molecules like vitamin A are slow, and large polar molecules and charged ions require transport proteins.
- Transport proteins like aquaporins and glucose transporters aid in the passage of molecules through the cell membrane.
- Endocytosis involves phagocytosis, pinocytosis, and receptor-mediated endocytosis, requiring ATP for engulfing extracellular material and digesting it within lysosomes.
- Exocytosis begins in the Golgi apparatus, packaging proteins and hormones into secretory vesicles that move towards the cell membrane, fuse with it, and release their contents into the extracellular space with the help of motor proteins and ATP.
