Enzyme Mechanisms and Specificity Quiz

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What type of specificity allows an enzyme to act on only one kind of functional group?

Stereospecificity

Group specificity (correct)

Absolute specificity

Linkage specificity

Which mechanism of catalysis involves an enzyme using side chains to donate or accept protons?

Covalent catalysis

Proximity

Acid-base catalysis (correct)

Metal ion catalysis

What role does Zn²⁺ play in the function of carbonic anhydrase?

It acts as an enzyme's active site template

It increases the overall thermodynamics

It forms covalent bonds with substrates

It stabilizes the negative charge and polarizes water molecules (correct)

Which statement best describes transition state stabilization?

Active sites promote transition state intermediates Signup and view all the answers

Which type of specificity refers to an enzyme's ability to selectively catalyze one stereoisomer over another?

Stereospecificity Signup and view all the answers

In enzyme reactions, what is primarily affected when increasing the concentration of substrate?

Enzyme saturation kinetics Signup and view all the answers

Which mechanism involves amino acid side chains forming temporary covalent bonds with substrates?

Covalent catalysis Signup and view all the answers

Which mechanism of enzyme action is NOT relevant for isomerases?

Proximity Signup and view all the answers

What happens to enzyme synthesis when tryptophan levels are high?

Repressor protein binds, halting enzyme synthesis. Signup and view all the answers

Which mechanism prevents self-digestion of digestive enzymes?

Activation by zymogens. Signup and view all the answers

How does phosphorylation affect glycogen synthase and glycogen phosphorylase?

Glycogen phosphorylase is activated while glycogen synthase is inactivated. Signup and view all the answers

What role does ATP play in the function of Aspartate Transcarbamoylase?

It activates the enzyme and enhances pyrimidine synthesis. Signup and view all the answers

What is a characteristic of multifunctional enzymes?

They possess multiple catalytic activities on a single polypeptide chain. Signup and view all the answers

Which of the following statements regarding allosteric control is true?

Binding of a ligand can shift the enzyme between tense and relaxed states. Signup and view all the answers

What is the effect of decreasing lactose consumption after weaning on lactase enzyme synthesis?

There is a decrease in lactase enzyme transcription. Signup and view all the answers

What is the primary reason for the cleavage of chymotrypsinogen into active α-chymotrypsin?

To prevent self-digestion during transport. Signup and view all the answers

What is the role of the aspartic acid side chain in the catalytic triad of chymotrypsin?

It takes a proton from the histidine side chain. Signup and view all the answers

What does a lower Km value indicate about an enzyme's substrate affinity?

The reaction can proceed with a smaller amount of substrate. Signup and view all the answers

In the context of enzyme kinetics, what occurs when the substrate concentration exceeds Km?

The enzyme reaction rate reaches Vmax. Signup and view all the answers

What is the function of the electrostatic catalysis in the enzymatic reaction described?

To stabilize the negative charge of the substrate. Signup and view all the answers

Which step in chymotrypsin's mechanism involves the formation of a tetrahedral transition state?

The hydrolysis of the peptide bond. Signup and view all the answers

What effect does a saturated enzyme have on the rate of reaction as substrate concentration increases?

The rate of reaction levels off and becomes independent of substrate concentration. Signup and view all the answers

Which factor is CRUCIAL for maintaining the pH during the enzymatic reaction involving bicarbonate?

The proton released maintains pH balance. Signup and view all the answers

What reaction does lysozyme primarily catalyze through acid-base catalysis?

Hydrolysis of glycosidic bonds in carbohydrates. Signup and view all the answers