Biochem Chapter 6 part 2

Where do competitive inhibitors bind on an enzyme, and how does this affect the enzyme's activity?

• At the allosteric site, decreasing the enzyme's activity by changing its shape.

• At the active site, preventing the substrate from binding.

• At the substrate, altering its structure.

• At the enzyme's surface, increasing the enzyme's activity.

Tags

NGSS.HS-PS1-2

Explain how temperature affects enzyme activity and provide an example of how this can be experimentally determined.

• Temperature increases enzyme activity indefinitely; measure reaction rate at various temperatures.

• Temperature decreases enzyme activity; observe enzyme denaturation at high temperatures.

• Enzyme activity increases with temperature up to an optimal point, then decreases; measure reaction rate at different temperatures to find the optimum.

• Temperature has no effect on enzyme activity; compare reaction rates at different temperatures.

Describe the role of pH in enzyme activity and how you would design an experiment to determine the optimal pH for a specific enzyme.

• pH has no effect on enzyme activity; use a single pH level for all experiments.

• Enzyme activity is highest at extreme pH levels; test enzyme activity at pH 1 and 14.

• Each enzyme has an optimal pH; measure enzyme activity across a range of pH levels to find the peak.

• Enzyme activity decreases with increasing pH; test activity at neutral pH only.

What is an allosteric enzyme, and how does it differ from a non-allosteric enzyme in terms of regulation?

• Allosteric enzymes are regulated by covalent modification; non-allosteric enzymes are not.

• Allosteric enzymes have multiple active sites; non-allosteric enzymes have only one.

• Allosteric enzymes are regulated by molecules binding at sites other than the active site, affecting activity; non-allosteric enzymes are not.

• Allosteric enzymes are always active; non-allosteric enzymes require activation.

Define feedback inhibition and provide an example of how it operates in a metabolic pathway.

• Feedback inhibition is when the end product of a pathway enhances the pathway's activity; an example is glycolysis.

• Feedback inhibition is when the end product of a pathway inhibits an earlier step; an example is the regulation of the citric acid cycle.

• Feedback inhibition is when an intermediate product inhibits the pathway; an example is protein synthesis.

• Feedback inhibition is when the initial substrate inhibits the pathway; an example is photosynthesis.

Tags

NGSS.HS-LS1-3

What is a positive effector in enzyme regulation, and how does it influence enzyme activity?

• A positive effector decreases enzyme activity by binding to the active site.

• A positive effector increases enzyme activity by binding to the allosteric site.

• A positive effector has no effect on enzyme activity.

• A positive effector increases enzyme activity by binding to the substrate.

Explain covalent modification and its role in enzyme regulation, providing an example.

• Covalent modification involves the permanent alteration of an enzyme's structure; an example is protein folding.

• Covalent modification involves reversible changes to an enzyme's structure, such as phosphorylation; an example is glycogen phosphorylase regulation.

• Covalent modification involves the addition of a cofactor; an example is hemoglobin.

• Covalent modification involves the removal of a substrate; an example is DNA replication.

Identify common modifying groups in covalent modification and the amino acids they typically modify.

• Phosphate groups modify lysine; methyl groups modify serine.

• Phosphate groups modify serine, threonine, and tyrosine; acetyl groups modify lysine.

• Methyl groups modify cysteine; acetyl groups modify arginine.

• Phosphate groups modify alanine; methyl groups modify histidine.

What are enzymes that add phosphates called, and what is their role in cellular processes?

• Phosphatases; they remove phosphates from proteins.

• Kinases; they add phosphates to proteins, often regulating activity.

• Dehydrogenases; they add phosphates to proteins.

• Ligases; they remove phosphates from proteins.

What are enzymes that remove phosphates called, and how do they contribute to enzyme regulation?

• Kinases; they add phosphates to proteins.

• Phosphatases; they remove phosphates from proteins, often deactivating them.

• Ligases; they add phosphates to proteins.

• Dehydrogenases; they remove phosphates from proteins.