Which of the following is not correct concerning the action of enzymes? a. An en

Question

Which of the following is not correct concerning the action of enzymes? a. An enzyme lowers the Energy of the products and thus makes the reaction more favorable. b. A 1:1 Enzyme-Substrate complex (ES) must be formed before the enzyme can convert the substrate to product. c. An enzyme speeds up both the forward reaction and the reverse reaction. d. Enzymes are stereoselective because the active site is 3-Dimensional and preferentially binds one enantiomer over the other. e. A mutational change of any residue in the active site of an enzyme has a significant effect on the activity of the enzyme. Procaine Hydrochloride is a local anesthetic often used by dentists. The structure shown to the right represents procaine in the active site of the enzyme procaine esterase. Consider this substrate in the active site of the enzyme to answer the next three questions. Assume pH 7. what type of residue might be located as a binding (recognition) residue at location #2? a. A polar noncharged residue that can form a Hydrogen bond. b. A negatively charged residue that can form an ion-ion interaction (salt bridge). c. A nonpolar residue that can be favorably involved in a hydrophobic interaction. d. A positively charged residue that can form a salt bridge. e. Any type of residue since there is no significant feature on the substrate to bind to. Which of the following might be a likely binding residue at location #3? a. Lys residue b. Ala residue c. Met residue d. Asp residue e. Phe residue Which of the following amino acid residue side chains would never be a catalytic residue in the active site of an enzyme? a. Serine b. Phenylalanine. c. Cysteine d. Glutamic acid e. Histidine Which of the following is correct concerning Michaelis Menten kinetics for enzyme catalyzed reactions? a. The V_max is obtained when [S] is equal to 2 K_M. b. K_M is equal to 1/2 V_max. c. The maximum velocity (V_max) occurs the when the enzyme is saturated with substrate. d. The kinetic plot of velocity vs. [S] is linear. e. A useful approximation is "The larger the K_M, the better the E to S binding."

Explanation / Answer

Answers:

1) b

More than one substrate can bind to enzymes during formation of ES complex, so 1:1 ES is not formed in all cases.

In enzymatic reaction, Enzyme react with the substrate to form the product. Every enzyme has an active site, the number of activesite can be more than one, so more number of substrates can bind.

For example, In plants, RUBISCO enzyme, which participate in photosynthesis has dual nature, it has two active sites, in which CO2 bind to one active site and O2 bind to another active site.

Due to enzymes, activation energy is reduced in completion of the reaction. Reactants have high energy, whereas products have lower energy.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.