Biochem ch 6

What effect does a catalyst have on the overall ΔG of a reaction?

• it depends on the catalyst

• it has no effect

• it raises the ΔG

• it lowers the ΔG

Which of the following are true about enzymes?

• Enzymes bind substrates with high specificity

• Enzymes have great catalytic power

• Enzymes use hydrophobic interactions exclusively when binding substrates

• The catalytic activity of enzymes is often regulated

The free energy change of a reaction _____

• if negative, enables the reaction to occur spontaneously.

• if positive, enables the reaction to occur spontaneously.

• is greater than zero when the reaction is at equilibrium.

• determines the rate at which a reaction will attain equilibrium.

The model that best describes a conformational change in enzyme structure upon binding substrate is referred to as:

• induced fit

• lock and key

Which of the following is the most effective way to increase the rate of a biochemical reaction?

• add a catalyst

• increase the conc of the reactants

• increase the temp

• increase or decrease the pH

Chymotrypsin catalyzes the hydrolysis of a peptide bond and is therefore categorized as a _____. 

• ligase

• hydrolase

• oxidoreductase

• lyase

The highest point in a reaction coordinate diagram represents  _____

• the reactants in exergonic rxn

• the products in endergonic rxn

• the transition state

• an intermediate in the rxn pathway

 How does a catalyst increase the rate of a reaction? 

• It makes the reaction more exergonic.

• It causes a localized increase in the concentration of the reactants.

• It allows reacting molecules to more easily form the transition state.

• It increases the temperature of the reaction.

An organic molecule that is tightly bound to an enzyme and participates  in an enzyme catalyzed reaction is specifically referred to as a ___

• prosthetic group

• cosubstrate

• metal ion

What three amino acids are found in the catalytic triad of chymotrypsin? 

• Cys, Lys, Glu

• Glu, His, Thr

• Ser, Arg, Cys

• Asp, His, Ser