Enzymatic reactions will always proceed faster than if there was no enzyme present. They will also often be coupled to hydrolysis reactions to drive them forward thermodynamically, such as ATP hyrodlysis to make an otherwise unfavorable reaction proceed. The equilibrium constant of an enzymatic reaction is never different than the constant for the same reaction without enyzme, however, and thus choice III is incorrect.

Adding more enzyme is the only way to make this reaction proceed faster. Since this is a reaction that takes place in the blood, the optimal conditions are 37 degrees Celsius and a pH of 7.4. Adding more substrate could help in certain conditions, but we know from the question that there is no free enzyme in the reaction so adding more would not help. Removing enzyme would obviously sow the reaction down.

Enzymes are biological catalysts that are responsible for the acceleration of the rate and specificity of many metabolic reactions. In order for rate acceleration to occur, an enzyme lowers the activation energy of a reaction. This allows for products to be formed more quickly and reactions to reach equilibrium more rapidly. Substrates bind to the active site of an enzyme and, in the presence of a large concentration of substrate, enzyme active sites become saturated and the reaction rate reaches a maximum constant. The equilibrium constant is calculated from the expression for chemical equilibrium, and is not affected by enzymes. Thus, the correct answer is to decrease the activation energy.

Fetal hemoglobin is associated with a left-shift due to its greater binding affinity for oxygen. The Michaelis constant, K_m, is defined as the substrate concentration at which the reaction rate is 0.5 * V_max. A low K_m indicates high substrate affinity. 

The correct answer is pyrimidine complex. A pyrimidine refers to a type of nucleotide base. Enzymes commonly have the suffix -ase at the end of their name.

Enzymes are unable to shift the equilibrium of a reaction. This is a commonly confused enzyme concept, but it should be known that, chemically speaking, only adding or removing reactants and/or products can shift the equilibrium of a reaction. Although this concept is mainly seen in chemisty, known as Le Chatelier's principle, this principle is surprisingly helpful and applicable to many fields of science, including biology. All other answer choices are functions of enzymes.

The rate of enzymatic activity can be increased in a few ways. Enzymes have optimal levels of acidity and temperature at which they function best. If this optimal level is exceeded, the enzyme will denature. Enzymes of the small intestine are adjusted to a relatively alkaline environment and will denature in acidic environments. Decreasing the temperature would decrease the rate of catalyzation. By increasing the amount of substrate, the enzyme will function faster. The level at which an enzyme's rate of catalyzation can no longer be made faster by the addition of substrate is referred to as its V_max.

Reaction rates are generally impacted by the concentration of the reactants in the reaction. The Km is the amount of substrate needed to attain a concentration resulting in half of the maximum rate achievable by an ezyme catalyzed reaction.

The maximum rate will be limited by the number of enzyme moleules available, and will be reached when the enzyme active sites are saturated.

The basement membrane and sub-basement structures are predominately made of protein (connective tissue). To infiltrate this region, a protease would be most appropriate. The remaining choices are all enzymes, but would not be capable of digesting appropriate proteins.

Cysteine has a sulfide (-SH) in its side chain, which can form covalent disulfide bonds. These bonds are often integral in creating protein tertiary structures.