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Unformatted text preview: Chemical Building Blocks of Life 13:27 Case: daughter with PKU, caught very early, checked in all newborns Easily treatable, can prevent symptoms by following a certain diet PKU Autosomal (not sex linked) recessive condition in which phenylalanine levels become excessive o Recessive parents are carriers, dont show symptoms, daughter must be homozygous recessive, have to have two copies of allele to have disease o Left to right pic regular person, add an OH group, people with disease dont have this enzyme to carryout reaction o Must follow a diet/avoid proteins that have phenylalanine, must maintain this diet until brain fully developed, things that have artificial sweetener sometimes have this Untreated symptoms: o Developmental delays: can baby sit up on its own, hold its neck up o Cognitive impairment: wont do well in school o Microcephaly (small head) o Seizures o Musty odor (breath and urine) Why does excess phenylalanine cause these problems? Biomolecules: molecules found in cells and living organisms Most have a carbon backbone Why carbon? Can form 4 covalent bonds which allows for great diversity of structures o Covalent: bond where atoms share valence electrons, strongest bond in biological system Polar and nonpolar based on electronegativities Nonpolar: equal sharing of e-, occurs between atoms with nearly identical electronegativities, hydrophobic (dont interact well with water bc no charge) important in biological systems since we are mostly water, dont want certain parts of body to be able to dissolve in water ex. Skin in rain Polar bonds: unequal sharing of e-, occurs between atoms with different electronegativities, results in partial negative and partial positive ends elctrostatic charges, water is polar, like repels like, hydrophilic o Electronegativity: ability to pull an electron towards itself o *carbon and hydrogen have similar electronegs, o hydrogen bonds: when partial postive H atom and partial negative atom (usually N or O) bond, ex. partial negative of O of water and partial positive of H on another water bond together, weak bond important for that bond to be able to break and reform ex. DNA transcription and translation want a strong bond for something structural What makes each biomolecule different? Functional groups: most increase solubility in water, impart characteristic chemical properties on molecules to which they are attached, change function of molecule o **be able to recognize functional groups from pictures and which are important to nucleic acids and which important to proteins...
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This note was uploaded on 06/23/2011 for the course BIO 212 taught by Professor Frederick during the Fall '07 term at Wofford.
- Fall '07