Chapter 3.4: Proteins: Molecules with Diverse Structures and Functions Flashcards
What are the seven functions of proteins?
- Enzyme catalysis
- Defense
- Transport
- Support
- Motion
- Regulation
- Storage
Define amino acid
the subunit structure from which proteins are produced, consisting of a central carbon atom with a carboxyl group (-COOH), an amino group (-NH2), a hydrogen, and a side group (R group); only the side group differs from one amino acid to another
What is the subunit structure from which proteins are produced, consisting of a central carbon atom with a carboxyl group (-COOH), an amino group (-NH2), a hydrogen, and a side group (R group); only the side group differs from one amino acid to another?
amino acid
Define peptide bond
the type of bond that links amino acids together in proteins through a dehydration reaction
What is the type of bond that links amino acids together in proteins through a dehydration reaction?
peptide bond
Define polypeptide
a molecule consisting of many joined amino acids; not usually as complex as a protein
What is a molecule consisting of many joined amino acids; not usually as complex as a protein?
polypeptide
Define primary structure
the specific amino acid sequence of a protein
What is the specific amino acid sequence of a protein?
primary structure
Define secondary structure
the bonding interactions between -CO and -NH groups of the primary structure
What is the bonding interactions between -CO and -NH groups of the primary structure?
secondary structure
Define alpha helix
a form of secondary structure in proteins where the polypeptide chain is wound into a spiral due to interactions between amino and carboxyl groups in the peptide backbone
What is a form of secondary structure in proteins where the polypeptide chain is wound into a spiral due to interactions between amino and carboxyl groups in the peptide backbone?
alpha helix
Define beta sheet
a form of secondary structure in proteins where the polypeptide folds back on itself one or more times to form a planar structure stabilized by hydrogen bonding between amino and carboxyl groups in the peptide backbone
What is a form of secondary structure in proteins where the polypeptide folds back on itself one or more times to form a planar structure stabilized by hydrogen bonding between amino and carboxyl groups in the peptide backbone?
beta sheet
Define tertiary structure
the folded shape of a protein, produced by hydrophobic interactions with water, ionic and covalent bonding between side chains of different amino acids, and van der Waal’s forces; may be changed by denaturation so that the protein becomes inactive
What is the folded shape of a protein, produced by hydrophobic interactions with water, ionic and covalent bonding between side chains of different amino acids, and van der Waal’s forces; may be changed by denaturation so that the protein becomes inactive?
tertiary structre
Define quaternary structure
the structural level of a protein composed of more than one polypeptide chain, each of which has its own tertiary structure
What is the structural level of a protein composed of more than one polypeptide chain, each of which has its own tertiary structure?
quaternary structure
Define motif
a substructure in proteins that confers function and can be found in multiple proteins
What is a substructure in proteins that confers function and can be found in multiple proteins?
motif
Define domain (protein_
a distinct modular region of a protein that serves a particular function in the action of the protein
What is a distinct modular region of a protein that serves a particular function in the action of the protein?
domain
Define chaperone protein
a class of enzymes that help proteins fold into the correct configuration and can refold proteins that have been misfolded or denatured
What is a class of enzymes that help proteins fold into the correct configuration and can refold proteins that have been misfolded or denatured?
chaperone protein
Define denaturation
the loss of the native configuration of a protein or nucleic acid as a result of excessive heat, extremes of pH, chemical modification, or changes in solvent ionic strength or polarity that disrupt hydrophobic interactions; usually accompanied by loss of biological activity
What is the loss of the native configuration of a protein or nucleic acid as a result of excessive heat, extremes of pH, chemical modification, or changes in solvent ionic strength or polarity that disrupt hydrophobic interactions; usually accompanied by loss of biological activity?
denaturation
Define dissaciation
in proteins, the reversible separation of protein subunits from a quaternary structure without altering their tertiary structure
What is in proteins, the reversible separation of protein subunits from a quaternary structure without altering their tertiary structure?
dissociation
