BIOLOGY 2B03 Lecture Notes - Hemoglobin, 2-Mercaptoethanol, Membrane Structure
31 Jan 2013
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Document Summary
Can grow, reproduce, process information, respond to stimuli, communicate, carry out chemical reactions. Lack membrane- bound nucleus and subcellular compartments. Organisms may be unicellular or exist in colonies e. g. bacteria, cyanobacteria. Cell containing membrane- bound nucleus and organelles that have specific functions. Cell activities are compartmentaliz ed e. g. red blood cell, neuron. Complex arrangements of cells in sheets, chains, balls; need direct e. g. alga connections e. g. intestinal epithelial sheets. Monomers; attached in linear array to form primary structure = polypeptide. Four components attached to central alpha carbon. 20 different kinds with same general structure. Side chains (r) affect protein structure and function. Differ in size, shape, charge, hydrophobicity, reactivity. Hydrophilic: charge-polarized e. g. molecules with oh/o- or . Hydrophobic: not electrically polarized; repelled by water; tend to be on inside; often aggregate e. g. oils, fats, saturated hydrocarbons. Form peptide bond by covalently bonding amino acids together into peptides. Linear sequence of aas is determine by nucleotide sequence of encoding genes.
