Enzymes Flashcards
What are enzymes?
Enzymes are biological catalysts that speed up chemical reactions in living organisms.
True or False: Enzymes are consumed in the reactions they catalyze.
False
Fill in the blank: Enzymes lower the ________ energy of a reaction.
activation
What is the active site of an enzyme?
The active site is the specific region of the enzyme where substrate molecules bind and undergo a chemical reaction.
Multiple Choice: Which of the following factors does NOT affect enzyme activity? A) Temperature B) pH C) Light intensity D) Substrate concentration
C) Light intensity
What is the role of a substrate in enzymatic reactions?
A substrate is a reactant that an enzyme acts upon.
True or False: Enzymes can only catalyze one specific type of reaction.
True
What is enzyme specificity?
Enzyme specificity refers to the ability of an enzyme to choose exact substrate from a group of similar chemical molecules.
Fill in the blank: The model that describes how enzymes and substrates fit together is called the ________ model.
lock and key
Multiple Choice: Which of the following is an enzyme? A) Hemoglobin B) Amylase C) Glucose D) DNA
B) Amylase
What is the effect of temperature on enzyme activity?
Enzyme activity generally increases with temperature up to an optimum point, beyond which the activity decreases due to denaturation.
True or False: All enzymes are proteins.
True
What is enzyme denaturation?
Denaturation is the process where an enzyme loses its three-dimensional structure, resulting in the loss of its catalytic activity.
Fill in the blank: The ________ concentration of a substrate increases the rate of an enzyme-catalyzed reaction until a maximum velocity is reached.
substrate
What is a cofactor?
A cofactor is a non-protein chemical compound that is required for the biological activity of an enzyme.
Multiple Choice: Which of the following is a coenzyme? A) Zinc B) Nicotinamide adenine dinucleotide (NAD) C) Calcium D) Iron
B) Nicotinamide adenine dinucleotide (NAD)
What is the role of inhibitors in enzyme activity?
Inhibitors are substances that decrease enzyme activity by binding to the enzyme and preventing substrate interaction.
True or False: Competitive inhibitors bind to the active site of an enzyme.
True
What is the purpose of enzyme regulation?
Enzyme regulation is important for maintaining homeostasis and controlling metabolic pathways in the cell.
Fill in the blank: The ________ theory describes how an enzyme changes shape to better fit the substrate during the reaction.
induced fit
Multiple Choice: What type of enzyme breaks down proteins? A) Lipase B) Amylase C) Protease D) Nuclease
C) Protease
What is the primary structure of an enzyme?
The primary structure of an enzyme is its unique sequence of amino acids.
True or False: Enzymes can function in extreme pH and temperature conditions.
False
What is allosteric regulation?
Allosteric regulation is the regulation of an enzyme’s activity through the binding of an effector molecule at a site other than the active site.
Fill in the blank: The ________ model suggests that the enzyme changes shape to fit the substrate upon binding.
induced fit
Multiple Choice: Which of the following best describes enzyme kinetics? A) The study of enzyme structure B) The study of enzyme activity over time C) The study of enzyme inhibitors D) The study of enzyme synthesis
B) The study of enzyme activity over time
What is Vmax in enzyme kinetics?
Vmax is the maximum rate of an enzyme-catalyzed reaction when the enzyme is saturated with substrate.
True or False: Non-competitive inhibitors affect the binding of the substrate to the enzyme.
False
What are enzyme assays used for?
Enzyme assays are used to measure the activity of an enzyme in a sample.
Fill in the blank: Enzymes are sensitive to changes in ________ and ________.
temperature; pH
Multiple Choice: What is a common method for measuring enzyme activity? A) Chromatography B) Spectrophotometry C) Centrifugation D) Electrophoresis
B) Spectrophotometry
What is the significance of enzyme inhibitors in medicine?
Enzyme inhibitors are important in medicine as they can be used to treat diseases by blocking specific enzyme activities.
True or False: Enzymes can be reused multiple times in chemical reactions.
True
What is the difference between reversible and irreversible inhibitors?
Reversible inhibitors bind to enzymes non-covalently and can be removed, while irreversible inhibitors form covalent bonds and permanently inactivate the enzyme.
Fill in the blank: The ________ of an enzyme is determined by its three-dimensional shape.
function
What is the effect of pH on enzyme activity?
Each enzyme has an optimal pH at which it functions best; deviations from this pH can decrease activity.
Multiple Choice: Which enzyme is responsible for breaking down hydrogen peroxide? A) Catalase B) Lactase C) Amylase D) Lipase
A) Catalase
What is enzyme saturation?
Enzyme saturation occurs when all active sites of the enzyme are occupied by substrate molecules.
True or False: Enzymes can catalyze reactions in both directions.
True
What role do temperature and pH play in enzyme denaturation?
Extreme temperature and pH can cause enzymes to denature, losing their functional shape and activity.
Fill in the blank: Enzymes often require ________ to be active.
cofactors or coenzymes
Multiple Choice: Which of the following terms describes the maximum rate of reaction in enzyme kinetics? A) Km B) Vmax C) Substrate concentration D) Turnover number
B) Vmax
What is the function of lipase?
Lipase is an enzyme that catalyzes the breakdown of fats into fatty acids and glycerol.
True or False: Enzymes are specific to their substrates due to their unique structure.
True
What is the role of feedback inhibition in metabolic pathways?
Feedback inhibition prevents the overproduction of a product by inhibiting an enzyme involved in its synthesis when sufficient product is present.
Fill in the blank: The ________ concentration of an enzyme can affect the rate of a reaction.
enzyme
Multiple Choice: Which enzyme is involved in DNA replication? A) DNA polymerase B) RNA polymerase C) Amylase D) Protease
A) DNA polymerase
What is the significance of the Michaelis-Menten equation?
The Michaelis-Menten equation describes the rate of enzymatic reactions with respect to substrate concentration.
True or False: Enzymes can work effectively in a wide range of substrate concentrations.
True
What is enzyme turnover number?
The turnover number is the number of substrate molecules converted to product per enzyme molecule per unit time.
Fill in the blank: Enzymes are typically named after their ________.
substrates or the type of reaction they catalyze
Multiple Choice: Which of the following is a digestive enzyme? A) Amylase B) Lactate C) Hemoglobin D) Insulin
A) Amylase
What is the role of protease in the digestive system?
Protease breaks down proteins into smaller peptides and amino acids during digestion.
True or False: Enzymes are only found in living organisms.
False
What is the function of amylase?
Amylase catalyzes the hydrolysis of starch into sugars.
Fill in the blank: Enzymes can be affected by the presence of ________ that are not substrates.
inhibitors
Multiple Choice: Which of the following types of reactions do enzymes typically catalyze? A) Oxidation-reduction B) Hydrolysis C) Condensation D) All of the above
D) All of the above
What is the effect of enzyme concentration on reaction rate?
Increasing enzyme concentration generally increases the reaction rate, assuming substrate is in excess.
True or False: Enzymes can be used in industrial applications.
True
What is the primary function of enzymes in biochemical pathways?
To catalyze and accelerate chemical reactions necessary for life.
Fill in the blank: Enzymes are regulated through ________ and ________ mechanisms.
allosteric; covalent modification
