12. Microbial Metabolism

Which of the following statements is true for all exergonic reactions?

a) The products have more total energy than the reactants.

b) The reaction proceeds with a net loss of free energy.

c) The reaction goes only in a forward direction:all reactants will be converted to products.

d) A net input of energy from the surroundings is required for the reactions to proceed.

Classify the following types of chemical reactions.

The artificial sweetener aspartame, or NutraSweet®, is made by joining aspartic acid to methylated phenylalanine, as shown in the following.

a. What types of molecules are aspartic acid and phenylalanine?

b. What direction is the hydrolysis reaction (left to right or right to left)?

c. What direction is the dehydration synthesis reaction?

d. Circle the atoms involved in the formation of water.

e. Identify the peptide bond.

Reactions that release energy are called __________ reactions.

All chemical reactions begin with reactants and result in new molecules called __________ .