12 terms

MBC Chapter 3

Which class(es) of amino acids possess side chains that would be unable to form hydrogen bonds with water?
amino acids with nonpolar side chains
What aspects of amino acid structure vary among different amino acids?
the components of the R-group
Which of the following most accurately lists elements of any protein's primary, secondary, tertiary, and quaternary structure (in that order)?
amino acid sequence, hydrogen bonding between backbone atoms, overall shape of a single polypeptide, combinations of tertiary structures
The final three-dimensional folding of protein molecules (tertiary structure) can result from which of the following types of chemical interactions?
hydrogen bonding, hydrophobic interactions, covalent bonding
Which of the following most accurately represents the correlation of a specific protein's function (in parentheses) with its structure (shape)?

porin (membrane pore); long fiber
trypsin (enzyme); globular
collagen (structural support); globular
TATA-binding protein (DNA-binding); long fiber
trypsin (enzyme); globular
Complete the following sentences about enzyme function:
(1) Enzymes speed reaction rates by _____ and lowering activation energy.
(2) Activation energies are reduced because enzymes stabilize _____.
(3) Enzyme specificity is a function of the shape of the active site and the chemical properties of _____.
1. orienting substrates; 2. the transition state; 3. the active site's R-groups
An enzyme has a total of four active sites. When you denature the molecule and study its composition, you find that each active site occurs on a different polypeptide. Which of the following hypotheses does this observation support?
The protein has quaternary structure.
The secondary structure of proteins results because of _____ bonding between molecules in the protein molecules' backbone.
Which of the following observations is the strongest argument in favor of the hypothesis that protein structure and function are correlated?
Denatured (unfolded) proteins do not function normally.
A series of hydrophobic side chains will congregate together as a protein folds in an aqueous solution and be stabilized by _____.
van der Waals interaction
In cells, the activity of enzymes is often regulated by other molecules. Why is this necessary?
because it is unlikely that all reaction products are required all of the time
The lock-and-key analogy for enzymes applies to the _____.
specificity of enzymes binding to their substrate