... environment. The major barrier of uptake for a toxicant is the cell membrane or cell wall at the site of uptake, for example; cell membrane of gastrointestinal tract or skin, epithelial cell of gill and tracheae, or cell wall of plant root. There are four principal processes involved in the movement of toxicants across the cell membrane. These include: passive diffusion, facilitated transport, active transport ... during the facilitated transport process. Active transport occurs when the toxicant's molecule is actively combined with a carrier. During the step of Pinocytosis the cell membr...

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• Approx Pages: 5
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• Grade Level: Undergraduate