1. What is the primary result of the proximity effect in enzyme catlysis?

A. Reduction in entropy and an increase in the effective molarities of substrates
B. Stabilization of the transition state
C. Transient covalent bonding of groups such as phosphate to position them near the substrate
D. Substrate-initiated conformational changes in the enzyme
E. Hydrogen bonding between the enzyme and substrate

2. Which amino acids are in the catalytic triad of the serine
proteases?

A. Thr-His-Ser
B. Ser-Arg-Glu
C. Lys-Ser-Arg
D. Ser-Arg-Lys
E. Ser-His-Asp

3. Chymotrypsin and trypsin cleave peptide bonds by virtually the same mechanism. Why does chymotrypsin cleave near residues like tyrosine, but trypsin does not?

A. The enzymes have different catalytic triads.
B. Tyrosine is too big to fit into trypsin's active site.
C. Chymotrypsin is a dimer and trypsin is a monomer.
D. Chymotrypsin has a very hydrophobic specificity pocket within its active site that binds tyrosine.
E. Trypsin is simply much slower at cleaving peptide bonds than chymotrypsin due to less flexibility in its active site.

4. What are the two chemical modes of enzyme catalysis?

A. Sn2 catalysis & Covalent catalysis
B. Covalent catalysis & Acid-base catalysis
C. Sn1 catalysis & Acid-base catalysis
A. Sn1 catalysis & Sn2 catalysis