BIOL 2520 Lecture Notes - Lecture 18: Symporter, Human Genome, Parietal Cell
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L e c t u r e 1 8 | 1. Read chapter 12: transport across all cell membranes. Active transport: active transport is the pumping of ions or molecules through a membrane against their concentration gradient. It always requires a trans-membrane (integral) protein usually called a transporter. Their presence in the cell membrane is regulated by the cell. Transport is coupled to the consumption of energy. The source of the energy for active transport. The source of the energy used in active transport is atp. The energy of atp may be used directly or indirectly: direct active transport -the transporter binds atp directly and uses the energy of its hydrolysis to drive active transport. Indirect active transport -the transporter uses the energy already stored in the gradient of a directly-pumped ion. Direct active transport of the ion establishes a concentration gradient.