Question

Theory of enzymes:

True or False:

___ Enzymes catalyze reactions by increasing the reaction free energy

___ Enzyme are remarkable for their substrate specificity.

___ Enzyme can convert light energy into chemical or mechanical energy

___ Catalytic residues in enzymes can include amino acid side chains, RNA bases, and other organic cofactors

___ Michaelis-Menten kinetic theory only applies to enzymes with single substrates

___ Enzymes bind transition-state analogs more tightly than substrates

___ At high substrate concentration, reactions are rare-limited by how rapidly enzymes convert substrates into products

___ K_m=K_D when k_cat>>k_-1

___ k_cat/K_{M is equivalent to a second-order rate constant}

___ Enzymes can use electrostatics to exceed the rate of diffusion (bimolecualr collision of substrate with enzyme's active site)

___ Drugs that bind to an allosteric site on an enzyme cause a decrease in k_cat

Answer 1

Dear Student, Kindly refer to the solution. Feel free to ask if you face difficulty in understanding any step of the solution attached, so that we can assist you in a better way.

1. Enzymes catalyze reactions by increasing the reaction free energy (False). Enzymes catalyze reactions by decreasing the free energy of activation, but they have no effect on free energy of reaction.

2. Enzyme are remarkable for their substrate specificity. ( True). The most remarkable characteristics of enzyme is their specificity towards a particular substrate.

3. Enzyme can convert light energy into chemical or mechanical energy. ( True).

4. Catalytic residues in enzymes can include amino acid side chains, RNA bases, and other organic cofactors. ( True)

5. Michaelis-Menten kinetic theory only applies to enzymes with single substrates. ( False)

6. Enzymes bind transition-state analogs more tightly than substrates. ( True)

7. At high substrate concentration, reactions are rare-limited by how rapidly enzymes convert substrates into products. (True)

8. (False) K_m=K_D when k_cat>>k_-1  .This will be true when k_cat<<k_-1

9. k_cat/K_{M is equivalent to a second-order rate constant}.(True)

10. Enzymes can use electrostatics to exceed the rate of diffusion.(True)

11. Drugs that bind to an allosteric site on an enzyme can cause a decrease in Kcat. (True).

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