#1
What is the primary function of enzymes in biological systems?
To lower the activation energy of reactions
ExplanationEnzymes facilitate biochemical reactions by reducing the energy required to initiate them.
#2
Which of the following is true regarding enzyme-substrate specificity?
Enzymes are highly specific and typically catalyze only one reaction with one or a few closely related substrates
ExplanationEnzymes exhibit specificity towards particular substrates due to complementary structures and interactions.
#3
What is the role of the active site in enzyme catalysis?
To bind and stabilize the enzyme-substrate complex
ExplanationActive sites are regions on enzymes where substrates bind and chemical reactions occur, facilitating substrate conversion.
#4
What is the Michaelis-Menten equation used to describe?
The rate of a chemical reaction in terms of reactant concentrations
ExplanationDescribes the rate of enzyme-catalyzed reactions with respect to substrate concentration.
#5
What is the turnover number of an enzyme?
The number of substrate molecules converted into product by one enzyme molecule per unit time
ExplanationQuantifies the efficiency of an enzyme in converting substrate to product.
#6
Which of the following factors does NOT affect enzyme activity?
Molecular weight of the enzyme
ExplanationEnzyme activity can be affected by various factors, but molecular weight typically does not directly influence it.
#7
What is the Lineweaver-Burk plot used for?
To determine the Michaelis constant (Km) and maximum velocity (Vmax) of an enzyme-catalyzed reaction
ExplanationGraphical method used to analyze enzyme kinetics and determine kinetic parameters.
#8
Which of the following is NOT a type of enzyme inhibition?
Allosteric activation
ExplanationEnzyme inhibition involves factors that decrease enzyme activity, whereas allosteric activation increases it.
#9
What is the function of an enzyme activator?
To increase the enzyme activity
ExplanationEnhances enzyme activity by promoting conformational changes or stabilizing the active form of the enzyme.
#10
Which of the following is NOT a characteristic of enzyme kinetics?
Enzyme kinetics remain constant regardless of environmental factors
ExplanationEnzyme kinetics are influenced by various factors, including temperature, pH, and substrate concentration.
#11
What is the role of a cofactor in enzyme catalysis?
To assist in catalytic activity by participating in the reaction
ExplanationCofactors aid enzymes by facilitating chemical reactions, often by binding to the enzyme's active site.
#12
What is allosteric regulation of enzymes?
Regulation of enzyme activity through the binding of molecules to sites other than the active site
ExplanationModulates enzyme activity by inducing conformational changes through binding at allosteric sites.
#13
What is the role of a coenzyme in enzyme catalysis?
To transfer chemical groups or electrons between molecules
ExplanationCoenzymes aid enzymes by shuttling functional groups or electrons during catalysis.
#14
What does the term 'kcat' represent in enzyme kinetics?
The turnover number of the enzyme
ExplanationDefines the rate at which an enzyme converts substrate to product when it is fully saturated with substrate.
#15
Which of the following is an example of a regulatory enzyme?
Hexokinase in glycolysis
ExplanationRegulatory enzymes control metabolic pathways by catalyzing key steps, such as hexokinase in glycolysis.
#16
What is the role of transition state analogs in enzyme catalysis?
To stabilize the transition state of the enzyme-substrate complex
ExplanationMimic transition states of enzyme-substrate interactions, aiding in the design of inhibitors or understanding catalytic mechanisms.
#17
Which of the following is NOT a characteristic of enzyme-substrate binding?
Enzymes form covalent bonds with substrates
ExplanationEnzyme-substrate binding typically involves non-covalent interactions such as hydrogen bonds and van der Waals forces.