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MCAT Org. Chem Ch.10
Term | Definition |
---|---|
α-Carbon Of An Amino Acid Is Attached: | Four groups which include an amino group, a carboxyl group, a hydrogen atom, and an R group. It is a chiral stereocenter in all amino acids except glycine. |
All Amino Acids In Eukaryotes Are: | L-amino acids. They all have (S) stereochemistry except cysteine, which is (R) |
Amino Acids Are Amphoteric, Meaning: | They can act as acids or bases |
Amino Acids Get Their Acidic Characteristics From: | Carboxylic acids |
Amino Acids Get Their Basic Characteristics From: | Amino groups |
In Neutral Solution, Amino Acids Tend To Exist As: | Zwitterions (dipolar ions) |
Amino Acids Can Be Classified By Their: | R groups |
Nonpolar, Nonaromatic Amino Acids Include: | Alanine, valine, leucine, isoleucine, glycine, proline, and methionine |
Aromatic Amino Acids Include: | Tryptophan, phenylalanine, and tyrosine |
Both Nonpolar Nonaromatic And Aromatic Amino Acids Tend To Be: | Hydrophobic and reside in the interior of proteins |
Polar Amino Acids Include: | Serine, threonine, asparagine, glutamine, and cysteine |
Negatively Charged Amino Acids Contain: | Carboxylic acids in their R groups and include aspartic acid and glutamic acid |
Positively Charged Amino Acids Contain: | Amines in their R groups and include arginine, lysine, and histidine |
Nonpolar Nonaromatic And Aromatic Amino Acids Tend To Be: | Hydrophobic and reside in the interior of proteins |
Polar, Negatively Charged (Acidic) And Positively Charged (Basic) Amino Acids Tend To Be: | Hydrophilic and reside on the surface of proteins in order to make hydrogen bonds with the aqueous environment |
Peptide Bonds Form By: | Condensation reactions and can be cleaved hydrolytically |
Resonance Of The Peptide Bond Restricts Motion About The: | C-N bond which takes on partial double-bond character |
Strong Acid Or Base Is Needed To: | Cleave a peptide bond |
Polypeptides Are Made Up Of: | Multiple amino acids linked by peptide bonds |
Proteins Are: | Large, folded, functional polypeptides |
The Strecker Synthesis Generates An Amino Acid From: | An aldehyde. |
Steps Of The Strecker Synthesis (First Part): | An aldehyde is mixed with ammonium chloride (NH4Cl) and potassium cyanide. The ammonia attacks the carbonyl carbon, which generates an imine. The imine is then attacked by the cyanide, which generates an aminonitrile. |
Steps Of The Strecker Synthesis (Second Part): | The aminonitrile is hydrolyzed by two equivalents of water, which generates an amino acid |
Gabriel Synthesis Generates An Amino Acid From: | Potassium phthalimidomalonic ester, diethyl bromomalonate, and an alkyl halide |
Steps Of The Gabriel Synthesis (First Two Parts): | Phthalimide attacks the diethyl bromomalonate, which generates a phthalimidomalonic ester. The phthalimidomalonic ester attacks an alkyl halide, which adds an alkyl group to the ester. |
Steps Of The Gabriel Synthesis (Last Two Parts): | The product is hydrolyzed, which creates phthalic acid (with two carboxylic groups) and converts teh esters into carboxylic acids. One carboxylic acid of the resulting 1,3-dicarbonyl is removed by decarboxylation. |
Phosphorus Is Found In Inorganic Phosphate (Pi), Which Is: | A buffered mixture of hydrogen phosphate (HPO4^-2) and dihydrogen phosphate (H2PO4-) |
Phosphorus Is Found In The Backbond Of DNA, Which Uses: | Phosphodiester bonds. In forming these bonds, a pyrophosphate (PPi, P2O7^-4) is released. Pyrophosphate can then be hydrolyzed to two inorganic phosphates. |
Phosphate Bonds Are Higher Energy Because Of: | Large negative charges in adjacent phosphate groups and resonance stabilization of phosphates |
Organic Phosphates Are: | Carbon-containing compounds that also have phosphate groups. |
Notable Examples Of Organic Phosphates Include: | Nucleotide triphosphates (ATP, GTP) and DNA |
Phosphoric Acid Has Three: | Hydrogens, each with a unique pKa. |
The Wide Variety In pKa Vvalues In Phosphoric Acid Act: | As a buffer over a large range of pH values. |