Biological Reactions In Cells Are Controlled By Enzymes Flashcards
What are enzymes?
Enzymes are biological catalysts that speed up biochemical reactions in cells.
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 region on the enzyme where the substrate binds.
What is a substrate?
A substrate is the reactant molecule that an enzyme acts upon.
What model describes how enzymes and substrates interact?
The lock and key model.
True or False: Enzymes can catalyze multiple different reactions.
False
What is the effect of temperature on enzyme activity?
Increased temperature generally increases enzyme activity up to a certain point, after which it may denature.
What is denaturation?
Denaturation is the process in which an enzyme loses its functional shape and activity due to external stressors.
How does pH affect enzyme activity?
Each enzyme has an optimal pH range where its activity is maximized; deviations can reduce activity.
What are coenzymes?
Coenzymes are organic molecules that assist enzymes in catalyzing reactions.
What are inhibitors?
Inhibitors are substances that decrease enzyme activity.
What is competitive inhibition?
Competitive inhibition occurs when an inhibitor competes with the substrate for the active site.
What is non-competitive inhibition?
Non-competitive inhibition occurs when an inhibitor binds to an enzyme away from the active site, changing its shape.
What is an enzyme’s turnover number?
The turnover number is the maximum number of substrate molecules converted to product by an enzyme per unit time.
Fill in the blank: Enzymes are often named after their __________.
substrates
What is the role of enzyme cofactors?
Cofactors are non-protein molecules that assist enzymes in their catalytic activity.
True or False: All enzymes are proteins.
False; some are RNA molecules called ribozymes.
What is the induced fit model?
The induced fit model suggests that the active site of an enzyme changes shape to fit the substrate upon binding.
What is substrate concentration’s effect on enzyme activity?
Increasing substrate concentration increases enzyme activity until a saturation point is reached.
What is enzyme specificity?
Enzyme specificity refers to the ability of an enzyme to choose exact substrates from a group of similar chemical molecules.
Fill in the blank: Enzymes can be affected by __________ and __________.
temperature; pH
What is enzyme regulation?
Enzyme regulation is the process of controlling enzymatic activity through various mechanisms.
What are allosteric sites?
Allosteric sites are sites on an enzyme where molecules can bind, causing a change in enzyme activity.
What is feedback inhibition?
Feedback inhibition is a regulatory mechanism where the end product of a metabolic pathway inhibits an upstream process.
What is the difference between a simple enzyme and a conjugated enzyme?
Simple enzymes consist only of proteins, while conjugated enzymes contain a non-protein component.
True or False: Enzymes can function in both forward and reverse reactions.
True
What is the significance of enzyme kinetics?
Enzyme kinetics studies the rates of enzyme-catalyzed reactions and how they change with varying conditions.
What is a reaction’s activation energy?
Activation energy is the minimum energy required for a chemical reaction to occur.
What are the two main types of enzyme inhibitors?
Competitive and non-competitive inhibitors.
Fill in the blank: The __________ model is used to describe enzyme-substrate interactions.
induced fit
What is the role of temperature in enzyme activity?
Temperature influences the kinetic energy of molecules, affecting the rate of enzyme activity.
What happens to enzymes at extremely high temperatures?
Enzymes may denature and lose their functional shape.
What is the effect of high substrate concentration on enzyme activity?
At high substrate concentrations, enzyme activity reaches a maximum rate, known as Vmax.
Fill in the blank: __________ are substances that enhance enzyme activity.
Activators
What is the importance of enzyme cofactors?
Cofactors are essential for the proper functioning of some enzymes by assisting in the catalytic process.
What is the role of ribozymes?
Ribozymes are RNA molecules that can catalyze biochemical reactions, similar to protein enzymes.
Fill in the blank: Enzymes can be affected by __________ and __________.
inhibitors; activators
What is the term for the maximum rate of an enzyme-catalyzed reaction?
Vmax
What factors can affect enzyme activity?
Temperature, pH, substrate concentration, and the presence of inhibitors or activators.
What is enzyme saturation?
Enzyme saturation occurs when all active sites of an enzyme are occupied by substrates.
What is the primary function of enzymes in biological systems?
To catalyze and regulate biochemical reactions.
True or False: Enzymes can be reused multiple times.
True
What is the significance of enzyme specificity?
Enzyme specificity ensures that enzymes catalyze only specific reactions, preventing undesired reactions.
Fill in the blank: Enzymes work best at their __________ temperature and pH.
optimal
What does the term ‘enzyme efficiency’ refer to?
Enzyme efficiency refers to the rate at which an enzyme converts substrate into product.
What role do competitive inhibitors play in enzyme activity?
Competitive inhibitors block the active site, preventing substrate binding.
What is a key characteristic of enzymes?
Enzymes are highly specific for their substrates.
True or False: Enzymes are influenced by the concentration of reactants.
True
What is the role of allosteric regulation?
Allosteric regulation modulates enzyme activity by binding to sites other than the active site.
Fill in the blank: Enzymes can be inhibited by __________.
toxins
What is the importance of the enzyme-substrate complex?
The enzyme-substrate complex is crucial for catalyzing the conversion of substrates into products.
What happens to enzyme activity when the temperature exceeds the optimal range?
Enzyme activity decreases, and the enzyme may denature.
What are the two main types of enzyme catalysis?
Lock and key and induced fit.
Fill in the blank: Enzymes are typically named using the suffix __________.
ase
What is the effect of pH on enzyme structure?
Extreme pH levels can disrupt hydrogen bonds and ionic bonds, leading to denaturation.
What is the significance of enzyme kinetics in biochemistry?
Enzyme kinetics helps in understanding how enzymes function and how they can be regulated.
What is the primary role of enzymes in metabolic pathways?
To facilitate and regulate biochemical reactions.
Fill in the blank: Enzymes can be __________ by environmental factors.
regulated
What does the term ‘enzyme inhibition’ refer to?
The process by which the activity of an enzyme is decreased.
How do temperature changes affect the rate of enzyme reactions?
Increased temperature usually increases reaction rates up to a point, after which enzyme activity declines.
Fill in the blank: The __________ of an enzyme is critical for its function.
structure
What is a common example of a coenzyme?
NAD+ (Nicotinamide adenine dinucleotide)
What happens to enzymes at low temperatures?
Enzyme activity is reduced due to decreased molecular movement.
Fill in the blank: Enzyme activity can be measured by the rate of __________ formation.
product
What is the role of feedback mechanisms in enzyme activity?
Feedback mechanisms regulate enzyme activity to maintain homeostasis in metabolic pathways.
What is enzyme specificity based on?
The specific shape and chemical properties of the enzyme and substrate.
Fill in the blank: Enzymes can lower the __________ energy needed to initiate a reaction.
activation
What is the significance of the Michaelis-Menten equation?
It describes the rate of enzyme-catalyzed reactions as a function of substrate concentration.
What is a key factor in determining an enzyme’s activity?
The concentration of substrate available.
Fill in the blank: The __________ model explains how enzymes can adjust to substrate binding.
induced fit
What are the common characteristics of enzymes?
They are specific, reusable, and affected by environmental conditions.
What is the role of temperature in enzyme catalysis?
Temperature affects kinetic energy and reaction rates, influencing enzyme activity.
What is the significance of enzyme-substrate complex stability?
A stable complex increases the likelihood of product formation.
Fill in the blank: Enzymes can be classified as __________ or __________.
simple; conjugated
What is the role of environmental factors in enzyme activity?
Environmental factors such as temperature and pH influence enzyme structure and function.
What does it mean for an enzyme to be ‘saturated’?
It means all active sites are occupied, and increasing substrate concentration won’t increase the reaction rate.
Fill in the blank: __________ inhibitors bind to the active site of an enzyme.
Competitive
What is the role of serine proteases?
Serine proteases are enzymes that cleave peptide bonds in proteins.
What does the term ‘enzyme activity’ refer to?
The rate at which an enzyme converts substrate into product.
Fill in the blank: Enzymes are __________ by inhibitors.
inhibited
What type of enzyme catalyzes the breakdown of starch into sugars?
Amylase.
Fill in the blank: Enzymes can undergo __________ when exposed to extreme conditions.
denaturation
What is the role of metal ions in enzyme function?
Metal ions can act as cofactors, assisting in the enzymatic reaction.
What is the term for the study of enzyme kinetics?
Enzyme kinetics.
Fill in the blank: Enzymes are specific to their __________.
substrates
