23 Questions
What determines the distinct properties of individual proteins?
The amino acid side chains
What is the stable spatial arrangement of polypeptide chain segments held together by hydrogen bonds between backbone groups called?
Secondary structure
How is the alpha helix stabilized?
By hydrogen bonds between backbone oxygen and hydrogen atoms
Which complex contains 20 subunits?
Mediator complex
What is the function of enzymes in cell reactions?
To stabilize transition state intermediates
Which enzyme catalyzes the breaking of peptide bonds?
Trypsin
How do enzymes regulate protein activity?
By phosphorylation
What is the role of E3 Ub ligase in protein degradation?
It transfers Ub to cysteine residue in E2
What is the main function of phosphatases?
To inactivate proteins
Where does proteolysis occur within the proteasome?
In the core formed by beta rings
What is the role of the Mediator complex?
To assemble at gene promoters
What type of motif consists of 2 alpha helices wound around each other?
Coiled-coil motif
What is the primary stabilizing force in the tertiary structure of proteins?
Hydrophobic interactions
Which amino acid is commonly found in beta turns due to its small R group?
Glycine
Which secondary structure is stabilized by hydrogen bonds between backbone oxygen and hydrogen atoms in amino acids on different strands?
Antiparallel beta sheet
What is the characteristic feature of the structure of a beta turn?
Reverses the direction of a polypeptide chain
What is the role of prolines in alpha helices?
They are usually excluded from alpha helices
Which representation emphasizes how beta strands and alpha helices are organized in a protein?
Ribbon diagram
What is the size range of supramolecular complexes in proteins?
10s to 100s of polypeptide chains
What is the tertiary structure of unactivated Hemagglutinin (HA) characterized by?
Proximal helix with terminal fusion peptide domain folded back into stalk of structure
What do EGF domains in proteins like Neu and Tissue plasminogen activator (TPA) contain?
EGF domain plus other domains
What type of motif is present in many DNA-binding proteins that help regulate transcription?
Zinc-finger motif
What is the driving force for hydrophobic residues to cluster together in the folded protein core?
Hydrophobic effect
Test your knowledge of polypeptide structure and proteins with this quiz. Explore the role of amino acid side chains, peptide bonds, and the properties of different proteins.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
