Enzymes
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AP Biology › Enzymes
Which model of enzyme substrate binding posits that there is a transition state that develops before the reactants undergo change
Catalysis
Lock and key
Induced fit
Conformational change
Explanation
The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit.
Which model of enzyme substrate binding posits that there is a transition state that develops before the reactants undergo change
Catalysis
Lock and key
Induced fit
Conformational change
Explanation
The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit.
The induced fit model better explains enzyme substrate binding than does the lock and key model. The induced fit model explains which of the following, that is not explained by the lock and key model
Broad specificity of enzymes
Narrow specificity of enzymes
Rigid structure of enzymes
Rigid structure of substrate
Explanation
The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit. The induced fit model accounts for the broad specificity of enzymes as the active site is not rigid, but can undergo a conformational change to better fit the substrate binding.
At what pH does pepsin best function?
Explanation
Pepsin is an enzyme in the stomach that digests proteins. Because it is active in the stomach, which is highly acidic, pepsin best functions at a low pH between 2 and 2.5.
Pepsinogen is secreted by chief cells and converted into active pepsin after catalyzation by hydrochloric acid. The acid is secreted by parietal cells in response to gastrin secretion by G cells. After the stomach contents enter the duodenum of the small intestine, the acid is neutralized by bicarbonate secretions from the pancreas. This prevents the acid from damaging the walls of the small intestine.
At what pH does pepsin best function?
Explanation
Pepsin is an enzyme in the stomach that digests proteins. Because it is active in the stomach, which is highly acidic, pepsin best functions at a low pH between 2 and 2.5.
Pepsinogen is secreted by chief cells and converted into active pepsin after catalyzation by hydrochloric acid. The acid is secreted by parietal cells in response to gastrin secretion by G cells. After the stomach contents enter the duodenum of the small intestine, the acid is neutralized by bicarbonate secretions from the pancreas. This prevents the acid from damaging the walls of the small intestine.
What are the reactants of enzyme-catalyzed reactions known as?
Substrates
Enzymes
Inhibitors
Products
Explanation
The reactants of enzyme-catalyzed reactions are known as substrates. Enzymes catalyze formation of products from their substrates. Inhibitors hinder the efficacy of enzymes, thereby decreasing the rate of reactions, and nucleotides are the monomers of DNA and RNA.
The induced fit model better explains enzyme substrate binding than does the lock and key model. The induced fit model explains which of the following, that is not explained by the lock and key model
Broad specificity of enzymes
Narrow specificity of enzymes
Rigid structure of enzymes
Rigid structure of substrate
Explanation
The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit. The induced fit model accounts for the broad specificity of enzymes as the active site is not rigid, but can undergo a conformational change to better fit the substrate binding.
What are the reactants of enzyme-catalyzed reactions known as?
Substrates
Enzymes
Inhibitors
Products
Explanation
The reactants of enzyme-catalyzed reactions are known as substrates. Enzymes catalyze formation of products from their substrates. Inhibitors hinder the efficacy of enzymes, thereby decreasing the rate of reactions, and nucleotides are the monomers of DNA and RNA.
How do enzymes increase reaction rates?
Increasing activation energy
Decreasing activation energy
Increasing temperature
Increasing pH
Explanation
Enzymes increase the rate of reactions through stabilizing the transition state, which decreases activation energy.
How do enzymes increase reaction rates?
Increasing activation energy
Decreasing activation energy
Increasing temperature
Increasing pH
Explanation
Enzymes increase the rate of reactions through stabilizing the transition state, which decreases activation energy.