Which of the following reaction aspects is a component of the net reaction catalyzed by a synthetase? (Select all that apply.) A high-energy phosphate bond is utilized. An adduct of the substrate interacts with an enzyme cofactor. A molecule is synthesized. A group shifts from one carbon to an adjacent carbon on the substrate.

The following reaction coordinate diagram charts the energy of a substrate molecule (S) as it passes through a transition state (X‡) on its way to becoming a stable product (P) alone or in the presence of one of two different enzymes (E1 and E2). How does the addition of either enzyme affect the change in Gibbs free energy (ΔG) for the reaction? Which of the two enzymes binds with greater affinity to the substrate? Which enzyme better stabilizes the transition state? Which enzyme functions as a better catalyst?

Which of the following statements regarding enzymes and transition states is true? stabilization of the transition state must be less than stabilization of ES for catalysis to occur binding of substrate to an enzyme often causes strain, thus promoting transition state formation the transition state conformation of an enzyme catalyzed reaction is identical to the conformation seen in the uncatalyzed transition state formation of the transition state always assures that the reaction will proceed to product none of the above are true

Which of the following statements regarding enzyme catalysis is false? All options are false. Once formed, the transition state slowly proceeds to forming the product at a rate determined by cofactor binding The free energy of binding of the enzyme to the transition state is more favorable than the free energy of binding of the enzyme to the substrate The substrate and active site of the enzyme are solvated to promote enzyme-substrate interaction Once formed, the product dissociates from the enzyme after ATP hydrolysis in order to regenerate the active site

Write the balanced reaction catalyzed by phophoenolpyruvate carboxylase (P PC). Remember to add any cofactors, and to draw the structure formulas (a line-bond representation is fine) for the main substrate and product of the reaction.

Which of the following is/are advantages of multienzyme complexes? Which of the following is/are advantages of multienzyme complexes? None of the options are advantageous They speed up reaction rates. Side reactions are limited by channeling The entire complex can be controlled as one unit.

When lead acts as a poison, it can do so either by replacing another ion (such as zinc) in the active site of an enzyme or by reacting with cysteine side chains to form covalent bonds. Which of these is irreversible and why? Match the items in the left column to the appropriate blanks in the sentences on the right. Reset Help a covalent bond When occurs between the active site (containing cystein) and the inhibitor (lead), replacement of an ion the substrate is excluded or the catalytic reaction is blocked. an ionic bond When occurs and the inhibitor (lead) replaces another ion. reaction with side chains The is an example of a permanent, irreversible change. ion exchange The is an example of a change that can be reversed.

Rearrange the following terms to show the process of enzymatic reaction. Use and + to complete the equation. enzyme enzyme-substrate complex enzyme product substrate Several important things should be noted about this reaction: 1. A/an because of the fit between their structures; 2. As a result, something happens to the example, it might be split in two at a particular location. 3. Then the and 4. The enzyme is again. 5. Note that the arrows in the formula for enzyme reaction point acts on a specific to form a/an molecule. For comes apart, yielding the in the reaction and is now free to react _- This means that the reaction is 6. An enzyme-substrate complex can simply go back to the the 7. The products of an enzymatic reaction can react with the enzyme to form the and again; 8. It, in turn, may again form the 9. Therefore, the same. and the may act to cause a to go either way.

What are enzymes? What distinguishes enzymes from regular chemical catalysts? On the specificity of enzyme action, please comment. Which factor accounts for their specificity the most? Describe the enzyme catalysis mechanism.

The classic concept of bond strain is more correctly described in what way? Select the correct response: The transfer of electron from one chemical moiety to another results to decrease in steric hindrance. The chemical bonds of the substrate is distorted due to the presence of metal ions in the vicinity of the active site. The transition state makes better contact with the enzyme than the substrate due to stabilization effect of various moieties in the active site. The electron cloud of the substrate is polarized by more electronegative moieties in the active site.