Biology 1002B Lecture Notes - Lecture 3: Cystic Fibrosis, Membrane Transport Protein, Transmembrane Protein
28 Feb 2016
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Document Summary
Sometimes molecules are too big to move through a transmembrane protein. Membrane bound vesicle contains molecules to be removed/secreted from the cell. Vesicle fuses with the plasma membrane at release. Cell brings in macromolecules too large for transmembrane import. One of the characteristics of life is the ability to respond to changes in the environment. At the cellular level this means perceiving and reacting to a signal: directly from the environment in single celled organisms, from the environment or from other cells in multi-cellular organisms. Transduction- may have any number of steps and mechanisms. Binding causes conformational change in protein: transmission of signal through plasma membrane. Initiates first step in signal cascade: triggers cellular response. Has no effect when injected into the cell. The extracellular signal molecule does not enter the cell. Signal cascade often involves phosphorylation of target molecules.
