Biochem Module 4 Exam Questions and Answers Latest Update 2025 Graded A+

Biochem Module 4 Exam Questions and Answers Latest Update 2025 Graded A+ enzyme that facilitates carbon dioxide transport from from tissues to lungs - Answers carbonic anhydrase enzymes that catalyze hydrolysis of peptide bonds - Answers proteolytic enzymes enzyme that can cleave any peptide bond - Answers pepsin enzyme that cleaves carboxyl side of lysine and arginine - Answers trypsin cleaves arg-gly bonds - Answers thrombin enzymes are highly _____ - Answers specific enzymes that catalyze redox reactions - Answers oxioreductases enzymes that transfer functional groups - Answers transferases enzymes that aid in hydrolysis - Answers hydrolyases enzymes that add atoms or functional groups to a double bond or removes them to form double bonds - Answers lyases enzymes that move functional groups within a molecule - Answers isomerases enzymes that join two molecules in a reaction powered by ATP hydrolysis - Answers ligases enzyme without a cofactor - Answers apoenzyme catalytically active enzyme with cofactor - Answers holoenzyme small organic molecules derived from vitamins - Answers coenzyme True of false: metals can be cofactors. - Answers true tightly bound coenzymes - Answers prosthetic group the free energy change provides information about the _____ but not the ____ of a reaction - Answers spontaneity, rate a reaction can take place spontaneously if deltaG is ____. This is an ____ reaction. - Answers negative, exergonic a reaction cannot take place spontaneously if deltaG is ____. this is an _____ reaction. - Answers positive, endergonic in a system at _____, there is no net change between the concentrations of the products and reactants, and deltaG is _____. - Answers equilibrium, 0 True or false: The mechanism affects deltaG - Answers false True of false: deltaG gives information on the rate of a reaction - Answers false True of false: enzymes alter the equilibria of a reaction - Answers false enzymes facilitate the formation of the _____ - Answers transition state the transition state is the ____ stable because it has the ____ free energy - Answers least, highest difference in free energy between the transition state and the substrate - Answers energy of activation enzymes lower the ____ - Answers activation energy substrate binds to specific region in enzyme called _____ - Answers active site free energy released by the formation of a large number of weak interactions between a complementary enzyme and substrate - Answers binding energy compounds that resemble the transition state of a region but are not capable of being acted on by the enzyme - Answers transition state analog Vmax is directly dependent on _____ concentration - Answers enzyme substrate concentration at with the reaction velocity is half its maximal value - Answers Km = michaelis constant some people have trouble digesting alcohol because of an inactive form of _____ - Answers aldehyde dehydrogenase all substrates must bind to the enzyme before any products are released. forms _____ - Answers sequential reaction, ternary complex one or more products are released before all substrates bind the enzymes. forms____ - Answers double-displacement reactions substituted enzyme intermediate True of false: Michaelis-Menton enzymes are not regulated by the cell. - Answers true the first reaction in a metabolic pathway is the _____ step - Answers committed when sufficient product is present it can bind _____ to the first enzyme thus _____ the committed step. This is known as _____. true of false: it binds at the active site. - Answers reversibly inhibiting feedback inhibition false ____ enzymes always catalyzes the committed step of metabolic pathways - Answers allosteric true or false: allosteric enzymes recognize inhibitory molecules and stimulatory molecules - Answers true True or false: allosteric enzymes conform to Michaelis-Menton kinetics - Answers false in the concerted model, enzymes exist in two forms: __ and __. Which is more stable and thus more common? In the absence of substrate, the two forms are in _____. - Answers R = relaxed/active T = tense/inactive T equilibrium the symmetry rule states that: - Answers all subunits or active sites of an enzyme must be in the same state Susbtrate binds more regularly to the _ forms than the _ form - Answers R, T the binding of substrate disrupts the T/R equilibrium in favor of _ - Answers R binds to R form at regulatory site, distinct from the active site, and stabilizes this form, thus increasing the concentration of R and making an R/S interaction more likely - lowers threshold - Answers positive effector binds to T and stabilizes it, thus increasing the concentration of the T form and decreasing the likelihood of an R/S interaction - raises threshold - Answers negative effector loss of allosteric regulation by an important enzyme in purine synthesis. leads to excess urate crystallizing in joints - Answers gout active site contains a reactant group, usually a powerful nucleophile, that becomes temporarily covalently modified in the course of catalysis - Answers covalent catalysis molecule other than water plays the role of a proton donor or acceptor - Answers acid-base catalysis brining two substrates into proximity and in the proper orientation on a single binding surface of an enzyme - Answers catalysis or approximation and orientation temperature _____ the rate of enzyme-catalyzed reactions, but at a certain temperature, the enzyme becomes _____ - Answers enhances, denatured most enzymes have a bell shaped curve for __, because this alters the _____ of residues at the