Skip to main content
Back

GOB Chemistry: Proteins and Amino Acids

Control buttons has been changed to "navigation" mode.
1/20

Terms in this set (20)

  • What is biochemistry?

    Biochemistry is the study of the chemistry of life, focusing on all chemical reactions in living organisms.

  • What are the four classes of biomacromolecules in the human body?

    The four classes are proteins, lipids, carbohydrates, and nucleic acids.

  • What roles do proteins play in the body?

    Proteins act as enzymes (catalysts), hormones, storage, transport, structural, protective, and contractile proteins.

  • What is the general structure of an amino acid?

    An amino acid has a central alpha carbon bonded to an amine group, a carboxylic acid group, a hydrogen atom, and a variable side chain (R group).

  • What is a chiral carbon?

    A chiral carbon is a carbon atom bonded to four different groups, resulting in non-superimposable mirror images called stereoisomers.

  • What are the types of isomers relevant to amino acids?

    Constitutional isomers differ in bonding order; stereoisomers have the same bonding order but differ in spatial arrangement, including enantiomers (mirror images) and diastereoisomers (not mirror images).

  • How are amino acids classified based on side chain properties?

    Amino acids are classified as nonpolar, neutral polar, acidic (negatively charged), or basic (positively charged) based on their side chains.

  • What are zwitterions in amino acids?

    Zwitterions are amino acids with both positive (amine) and negative (carboxylate) charges, typically at physiological pH (~7).

  • Which amino acid side chains are charged at physiological pH?

    Acidic side chains carry a negative charge; basic side chains carry a positive charge at pH 7.

  • What is the primary structure of a protein?

    The primary structure is the linear sequence of amino acids linked by peptide bonds, written from N-terminus to C-terminus.

  • Why are glycine, proline, and cysteine considered shape-determining amino acids?

    Glycine is flexible due to its small side chain; proline is rigid due to its cyclic structure; cysteine forms disulfide bonds stabilizing protein structure.

  • What are the main types of secondary protein structures?

    The main secondary structures are the alpha-helix and the beta-pleated sheet, stabilized by hydrogen bonds between backbone amide groups.

  • What interactions stabilize protein structures at different levels?

    Primary: covalent peptide bonds; Secondary: hydrogen bonds; Tertiary and Quaternary: hydrophobic interactions, hydrogen bonds, ionic bonds (salt bridges), and disulfide bonds.

  • What is the hydrophobic effect in protein folding?

    Nonpolar side chains exclude water and pack inside the protein, driving folding and stabilizing the tertiary structure.

  • How is an alpha-helix stabilized?

    By hydrogen bonds between the amide hydrogen of one amino acid and the carbonyl oxygen four residues earlier, forming a right-handed coil.

  • How are beta-pleated sheets stabilized?

    By hydrogen bonds between amide groups on adjacent beta-strands, which can be parallel or antiparallel.

  • What is a peptide bond?

    A peptide bond is a covalent amide bond formed between the carboxyl group of one amino acid and the amine group of another, releasing water.

  • What is the role of disulfide bonds in proteins?

    Disulfide bonds form covalent links between cysteine residues, stabilizing the folded tertiary and quaternary structures.

  • Which amino acid class prefers hydrophobic environments?

    Nonpolar amino acids prefer hydrophobic environments and tend to be buried inside proteins away from water.

  • What functional groups in amino acids can act as hydrogen bond donors?

    The amine group and amide group can donate hydrogen bonds; carbonyl groups act as acceptors.