Enzymes quiz #2 Flashcards
Enzymes quiz #2
You can tap to flip the card.
Control buttons has been changed to "navigation" mode.
1/40Skip to main content
What is the difference between the substrate and the product in an enzyme-catalyzed reaction?
The substrate is the molecule that binds to the enzyme and is converted into the product during the reaction. How does the presence of an enzyme affect the reaction progress over time?
The presence of an enzyme increases the rate at which substrate is converted to product, allowing equilibrium to be reached more quickly. What is meant by the term 'enzyme catalysis'?
Enzyme catalysis refers to the acceleration of a chemical reaction by an enzyme. Why do enzymes not affect the equilibrium constant of a reaction?
Because enzymes only lower the activation energy and do not change the relative energies of reactants and products. What is the effect of an enzyme on the rate of the reverse reaction?
Enzymes can also increase the rate of the reverse reaction, helping the system reach equilibrium faster. What is the importance of enzyme specificity?
Enzyme specificity ensures that enzymes catalyze only particular reactions, contributing to the regulation and efficiency of metabolic pathways. What is the main takeaway regarding the function of enzymes in chemical reactions?
Enzymes speed up the rate at which equilibrium is reached by lowering activation energy, without altering equilibrium concentrations or ΔG. What is the role of enzymes in catabolic pathways?
Enzymes catalyze the breakdown of complex molecules into simpler ones, releasing energy. What is the role of enzymes in anabolic pathways?
Enzymes catalyze the synthesis of complex molecules from simpler ones, often requiring energy input. How does enzyme concentration affect the rate of a reaction?
Increasing enzyme concentration generally increases the reaction rate, up to a point where substrate becomes limiting. What is meant by the term 'globular protein' in the context of enzymes?
A globular protein is a protein with a compact, spherical shape, which is typical of most enzymes. Why is the study of enzyme kinetics important in biochemistry?
It helps us understand how enzymes function, how they are regulated, and how they affect metabolic pathways. What is the effect of temperature on enzyme activity?
Temperature can increase enzyme activity up to an optimal point, after which activity decreases due to denaturation. What is the effect of pH on enzyme activity?
Each enzyme has an optimal pH range; deviations can reduce activity or denature the enzyme. What is the difference between a cofactor and a coenzyme?
A cofactor is a non-protein chemical that assists enzyme activity, while a coenzyme is an organic cofactor, often derived from vitamins. What is the function of cofactors in enzyme activity?
Cofactors help enzymes catalyze reactions, often by stabilizing the enzyme or participating in the reaction. What is the function of coenzymes in enzyme activity?
Coenzymes act as carriers for chemical groups or electrons during enzymatic reactions. What is the difference between a holoenzyme and an apoenzyme?
A holoenzyme is the active enzyme with its cofactor, while an apoenzyme is the inactive protein portion without its cofactor. What is enzyme inhibition?
Enzyme inhibition is the decrease in enzyme activity due to the presence of a specific molecule that interferes with substrate binding or catalysis. What is competitive inhibition?
Competitive inhibition occurs when an inhibitor binds to the active site, blocking substrate binding. What is noncompetitive inhibition?
Noncompetitive inhibition occurs when an inhibitor binds to a site other than the active site, altering enzyme activity. What is allosteric regulation of enzymes?
Allosteric regulation involves the binding of a molecule at a site other than the active site, causing a conformational change that affects enzyme activity. What is feedback inhibition in metabolic pathways?
Feedback inhibition is when the end product of a pathway inhibits an enzyme involved earlier in the pathway, regulating the pathway's activity. What is the induced fit model of enzyme activity?
The induced fit model suggests that the enzyme changes shape upon substrate binding to better fit and catalyze the reaction. What is the lock-and-key model of enzyme activity?
The lock-and-key model proposes that the enzyme's active site is a perfect fit for the substrate, like a key fitting into a lock. What is enzyme saturation?
Enzyme saturation occurs when all active sites are occupied by substrate, and increasing substrate concentration no longer increases the reaction rate. What is the Michaelis-Menten constant (Km)?
Km is the substrate concentration at which the reaction rate is half of its maximum value (Vmax). What is Vmax in enzyme kinetics?
Vmax is the maximum rate of an enzyme-catalyzed reaction when the enzyme is saturated with substrate. What is turnover number (kcat) in enzyme kinetics?
Turnover number (kcat) is the number of substrate molecules converted to product per enzyme molecule per unit time when the enzyme is fully saturated. What is the significance of a low Km value?
A low Km indicates high affinity between the enzyme and its substrate. What is the significance of a high Km value?
A high Km indicates low affinity between the enzyme and its substrate. What is the effect of a competitive inhibitor on Km and Vmax?
A competitive inhibitor increases Km but does not affect Vmax. What is the effect of a noncompetitive inhibitor on Km and Vmax?
A noncompetitive inhibitor decreases Vmax but does not change Km. What is enzyme specificity?
Enzyme specificity refers to the enzyme's ability to select and catalyze only a particular substrate or type of reaction. What is a zymogen?
A zymogen is an inactive precursor of an enzyme that requires a biochemical change to become active. What is the role of temperature in enzyme denaturation?
High temperatures can disrupt the enzyme's structure, leading to loss of activity, or denaturation. What is the effect of extreme pH on enzyme activity?
Extreme pH can alter the enzyme's structure and active site, reducing or eliminating activity. What is the function of the enzyme-substrate complex in catalysis?
The enzyme-substrate complex positions the substrate for the reaction and stabilizes the transition state, facilitating catalysis. What is the difference between reversible and irreversible enzyme inhibition?
Reversible inhibition can be undone by removing the inhibitor, while irreversible inhibition permanently inactivates the enzyme. What is the role of enzymes in homeostasis?
Enzymes regulate metabolic reactions, helping maintain stable internal conditions in organisms.
02:54
