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BILD 1 Notes - BILD 1 Notes Lecture 2 Jan 5 The four major...

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BILD 1 Notes Lecture 2 – Jan 5 - The four major elements of life in organic compounds are H, O, C, N o Makes up 96% of living matter - Polar covalent bonds form when one electronegative element in a compound pulls electrons closer to itself o H2O is polar, while CH is nonpolar - Ionic bonds occur in interactions between DNA and proteins (cations and anions) o Transfer of electrons between atoms to form two ions bonded together NaCl forms crystal table salt (not a molecule but an ionic compound) - Hydrogen bonds play an important role in the formation of protein structures o Forms from H—O reactions between slightly positive H and negative Oxygen H is shared between polar molecules o Occurs with multiple H2O molecules and NH3 and H2O compounds o Water, because of its Hydrogen bonds becomes a good solvent that forms charged cages around ions that dissolve and break up ionic compounds and biological molecules that carry a chard like lysozymes and other enzymes and proteins - Hydrophilic substances – soluble in water, polar or charged (ionic) o NH3, NaCl, polar or charged parts of proteins - Hydrophobic substances-non-soluble in water, uncharged, non-polar o Lipids – dominant bonds are C-C and C-H with equal sharing of electrons Oils and fats - Van der Waals interactions occur with dipoles in phospholipids in a membrane o Allows geckos to climb walls from tiny hairs on their fingers o Relatively weak interactions, but can be strengthened by many molecules Lecture 3 – Jan 7 - pH = -log [H+], pOH = -log [OH-] o acids increases [H+] while bases increase [OH-] and reduces [H+] carbonic acid (CO(OH)2) donates an H+ ion and becomes a Bicarbonate ion (CO2OH)- This is known as a weak acid and is commonly found in the blood and keeps the pH of the blood to 7.4 (known as a buffer system) Strong Base – Sodium Hydroxide (NaOH) in aqueous solution dissociates immediately into sodium and hydroxide ions and increase [OH-] and decreases [H+] therefore raising the pH Bases can also act by absorbing H+ ions NH3 + H+ -> NH4+ (ammonium ion decreases [H+] and raises pH) - Organic Molecules o Carbon-based o Can be small to gigantic o Generally fall into 4 major groups Carbohydrates, lipids, nucleic acids, proteins o Vary in the structure of the carbon skeleton to form isotopes based on layout Can form rings like cyclohexane (C6H12) and benzene (C6H6)
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o Biological molecules contain other functional groups Cysteine and ATP (nucleotide) Carboxyl group ( COOH) Contained in all amino acids, makes them acids Amino group (NH2) Also contained in every amino acid Tends to work like ammonia as a weak base Sulfhydryl group (SH) Plays important role in maintaining shape of protein When two SH’s come together, they drop their hydrogens to form covalent bonds and hold things together Hydroxide group (OH) Found in all alcohols like ethanol and in ATP nucleotides
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