Question

consider the example of peptide bond formation between two amino acids, such as the valines shown in the ball-and-stick models. which of the following would best solve the \spatial orientation problem\ so that reaction rates would increase? choose the single best answer.
lower the concentration of amino acids, so that they are less likely to bump into each other at random.
cool the reaction solution to low temperature, so that each amino acid is moving around, at random, at lower speeds.
a molecule binds the two amino acids in such a way that the amino group on one is placed against the carboxyl group of the second.

Explanation:

The spatial orientation problem refers to the need for reactants (in this case, amino acids) to be oriented correctly for a reaction (peptide bond formation) to occur. Lowering the concentration or cooling the solution would not address the orientation but rather reduce the frequency of collisions. A molecule that binds the two amino acids to position the amino group of one against the carboxyl group of the other directly addresses the spatial orientation needed for the reaction.

Answer:

A molecule binds the two amino acids in such a way that the amino group on one is placed against the carboxyl group of the second.