Enzymes quiz #1 Flashcards
Enzymes quiz #1
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What are enzymes and what is their primary function in biochemical reactions?
Enzymes are primarily globular proteins that catalyze chemical reactions by speeding up the rate at which equilibrium is reached without being consumed in the process. What is the active site of an enzyme?
The active site is the specific region of an enzyme where the substrate binds and the chemical reaction is catalyzed. What is an enzyme-substrate complex?
An enzyme-substrate complex is a temporary structure formed when a substrate binds to the active site of an enzyme. Do enzymes convert all substrate into product in a reaction?
No, enzymes do not convert all substrate into product; they help the reaction reach equilibrium faster, where both substrate and product are present. How do enzymes affect the energy of activation in a chemical reaction?
Enzymes lower the energy of activation, making it easier for the reaction to proceed and increasing the reaction rate. Do enzymes alter the thermodynamic favorability (ΔG) of a reaction?
No, enzymes do not change the thermodynamic favorability (ΔG) of a reaction. Do enzymes change the equilibrium constant (Keq) of a reaction?
No, enzymes do not change the equilibrium constant (Keq) of a reaction. What is the main difference between an enzyme-catalyzed and an uncatalyzed reaction?
An enzyme-catalyzed reaction reaches equilibrium faster due to a lower energy of activation, while the overall equilibrium position and ΔG remain unchanged. What are ribozymes?
Ribozymes are RNA molecules that act as enzymes, catalyzing chemical reactions. Are all enzymes proteins?
No, not all enzymes are proteins; some, like ribozymes, are made of RNA. What are substrates in the context of enzyme activity?
Substrates are the reactants that bind to an enzyme's active site and are converted into products. What happens to an enzyme after a reaction is complete?
The enzyme returns to its original state and can catalyze additional reactions. How do enzymes impact the speed of chemical reactions?
Enzymes increase the speed of chemical reactions by lowering the activation energy required. What is the transition state in a chemical reaction?
The transition state is a high-energy, unstable intermediate between reactants and products. How do enzymes interact with the transition state?
Enzymes stabilize the transition state, lowering the activation energy needed for the reaction. What is the energy of activation (Ea) in a reaction?
The energy of activation is the energy difference between the reactants and the transition state, required to initiate a reaction. What does it mean that enzymes are not consumed in reactions?
It means enzymes are not permanently altered or used up during the reaction and can be reused. Can enzymes catalyze reactions in both directions?
Yes, enzymes can catalyze both the forward and reverse reactions, helping the system reach equilibrium faster. What is the effect of an enzyme on the concentrations of substrate and product at equilibrium?
Enzymes do not change the equilibrium concentrations of substrate and product; they only help reach equilibrium faster. What is the role of enzymes in metabolic pathways?
Enzymes facilitate and regulate the chemical reactions in metabolic pathways, including both anabolic and catabolic processes. What type of protein structure do most enzymes have?
Most enzymes have a globular protein structure. What is meant by enzyme kinetics?
Enzyme kinetics is the study of the rates of enzyme-catalyzed reactions and how they change in response to various conditions. What is the relationship between activation energy and reaction rate?
A lower activation energy results in a faster reaction rate. What is the equilibrium constant (Keq) in a chemical reaction?
The equilibrium constant (Keq) is the ratio of the concentration of products to reactants at equilibrium. How do enzymes affect the kinetics of a reaction?
Enzymes increase the kinetics, or speed, of a reaction by lowering the activation energy. What is the difference between anabolic and catabolic reactions?
Anabolic reactions build complex molecules from simpler ones, while catabolic reactions break down complex molecules into simpler ones. Why is the study of enzyme mechanisms important?
Understanding enzyme mechanisms is crucial for grasping how metabolic pathways are regulated and how reactions are catalyzed in living organisms. What happens to the rate of a reaction if the activation energy is high?
If the activation energy is high, the reaction rate is slow. What is the main function of the active site in an enzyme?
The active site binds the substrate and facilitates its conversion to product. What is meant by the term 'catalyst' in biochemistry?
A catalyst is a substance that increases the rate of a chemical reaction without being consumed or permanently changed. How do enzymes differ from inorganic catalysts?
Enzymes are typically highly specific for their substrates and operate under mild biological conditions, unlike many inorganic catalysts. What is the significance of the enzyme-substrate complex?
The enzyme-substrate complex is essential for catalysis, as it brings the substrate into the correct orientation and environment for the reaction. What does it mean for a reaction to be at equilibrium?
At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction, and the concentrations of reactants and products remain constant. Can enzymes change the direction of a reaction?
No, enzymes do not change the direction of a reaction; they only speed up the rate at which equilibrium is reached. What is the effect of an enzyme on the free energy change (ΔG) of a reaction?
Enzymes do not affect the free energy change (ΔG) of a reaction. Why is it important that enzymes are not consumed in reactions?
Because they can be reused to catalyze multiple rounds of the same reaction, increasing efficiency. What is the role of enzymes in achieving equilibrium in a reaction?
Enzymes help the reaction reach equilibrium faster by lowering the activation energy. What is a common misconception about enzyme-catalyzed reactions?
A common misconception is that enzymes convert all substrate into product, but in reality, they only help reach equilibrium faster. What is the relationship between enzyme structure and function?
The specific three-dimensional structure of an enzyme determines its ability to bind substrates and catalyze reactions. What is the significance of the transition state in enzyme catalysis?
Enzymes stabilize the transition state, lowering the activation energy and increasing the reaction rate.
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