Podcast
Questions and Answers
What is the primary role of enzymes in the human body?
What is the primary role of enzymes in the human body?
- To provide structural support to cells
- To transport nutrients across cell membranes
- To release energy from food
- To accelerate biological processes (correct)
Which of the following statements is true about ribozymes?
Which of the following statements is true about ribozymes?
- They do not catalyze chemical reactions
- They can catalyze reactions among RNAs (correct)
- They are found only in the liver
- They are solely composed of protein
What happens to an enzyme's activity when its structure is denatured due to heat?
What happens to an enzyme's activity when its structure is denatured due to heat?
- It loses its enzymatic activity (correct)
- It remains functional but slows down
- It changes its substrates
- Its activity increases significantly
What determines the catalytic activity of an enzyme?
What determines the catalytic activity of an enzyme?
What type of molecules typically act as substrates for enzymes?
What type of molecules typically act as substrates for enzymes?
In which part of the body do intracellular enzymes primarily function?
In which part of the body do intracellular enzymes primarily function?
Which of the following enzyme sizes is true based on provided information?
Which of the following enzyme sizes is true based on provided information?
What role do enzymes in the circulatory system play?
What role do enzymes in the circulatory system play?
What happens to enzyme activity once all enzyme molecules are occupied by substrate?
What happens to enzyme activity once all enzyme molecules are occupied by substrate?
Which statement correctly describes a competitive inhibitor?
Which statement correctly describes a competitive inhibitor?
How does an increase in substrate concentration initially affect enzyme activity?
How does an increase in substrate concentration initially affect enzyme activity?
Which of the following factors does NOT affect enzyme activity?
Which of the following factors does NOT affect enzyme activity?
What role do enzymes play in the human body?
What role do enzymes play in the human body?
What constitutes the active site of an enzyme?
What constitutes the active site of an enzyme?
Which classification of enzymes catalyzes oxidation and reduction reactions?
Which classification of enzymes catalyzes oxidation and reduction reactions?
What type of enzyme is pepsin?
What type of enzyme is pepsin?
Which enzyme catalyzes the joining of two fragments of DNA?
Which enzyme catalyzes the joining of two fragments of DNA?
In the induced-fit model, what does the binding of the substrate induce?
In the induced-fit model, what does the binding of the substrate induce?
What is a cofactor?
What is a cofactor?
What mechanism of catalysis involves the formation of a covalent bond between substrate and enzyme?
What mechanism of catalysis involves the formation of a covalent bond between substrate and enzyme?
What role does activation energy play in enzyme-catalyzed reactions?
What role does activation energy play in enzyme-catalyzed reactions?
What is the primary function of transferases?
What is the primary function of transferases?
Which of the following is NOT a type of enzyme classification?
Which of the following is NOT a type of enzyme classification?
Which process demonstrates the effect of enzyme action in fermentation?
Which process demonstrates the effect of enzyme action in fermentation?
What type of enzymes catalyzes the rearrangement of molecular structures?
What type of enzymes catalyzes the rearrangement of molecular structures?
The process in which alcohol is produced from fermentation largely depends on which factor?
The process in which alcohol is produced from fermentation largely depends on which factor?
What happens to substrate and enzyme during the transition state?
What happens to substrate and enzyme during the transition state?
What component of the enzymatic action is referred to as the transition state?
What component of the enzymatic action is referred to as the transition state?
Which amino acids are primarily involved in enzyme active site catalysis?
Which amino acids are primarily involved in enzyme active site catalysis?
How do enzymes affect the activation energy of reactions?
How do enzymes affect the activation energy of reactions?
What happens to enzyme activity at temperatures higher than the optimum level?
What happens to enzyme activity at temperatures higher than the optimum level?
Which factor does not influence enzyme activity?
Which factor does not influence enzyme activity?
What is a key characteristic of biological catalysts?
What is a key characteristic of biological catalysts?
What defines the specificity of an enzyme?
What defines the specificity of an enzyme?
How does substrate concentration affect the rate of enzymatic reactions?
How does substrate concentration affect the rate of enzymatic reactions?
In which pH range do most enzymes exhibit optimal activity?
In which pH range do most enzymes exhibit optimal activity?
Which statement best describes the role of allosteric regulation in enzyme activity?
Which statement best describes the role of allosteric regulation in enzyme activity?
What is the first step in the catalytic action of enzymes?
What is the first step in the catalytic action of enzymes?
What is denaturation in the context of enzymes?
What is denaturation in the context of enzymes?
Which process describes how enzymes lower activation energy?
Which process describes how enzymes lower activation energy?
What occurs during the disintegration of the enzyme-substrate complex?
What occurs during the disintegration of the enzyme-substrate complex?
Flashcards
What are enzymes?
What are enzymes?
Enzymes are biological catalysts, mostly proteins, that speed up chemical reactions in living organisms without being consumed in the process.
What is a substrate?
What is a substrate?
The molecule that an enzyme acts upon is called a substrate. Enzymes bind to their specific substrates and convert them into different molecules called products.
What is the active site of an enzyme?
What is the active site of an enzyme?
The shape of an enzyme determines its function. The active site is a specific region on the enzyme where the substrate binds and the reaction takes place.
What is denaturation?
What is denaturation?
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What is the optimal temperature and pH for enzymes?
What is the optimal temperature and pH for enzymes?
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What are ribozymes?
What are ribozymes?
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What are intracellular enzymes?
What are intracellular enzymes?
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Why are enzymes important?
Why are enzymes important?
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Active site
Active site
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Cofactor
Cofactor
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Apoenzyme
Apoenzyme
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Holoenzyme
Holoenzyme
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Oxidoreductases
Oxidoreductases
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Transferases
Transferases
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Hydrolases
Hydrolases
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Lyases
Lyases
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Isomerases
Isomerases
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Ligases
Ligases
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Substrate
Substrate
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Activation energy
Activation energy
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Induced-fit model
Induced-fit model
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Catalysis by bond strain
Catalysis by bond strain
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Covalent catalysis
Covalent catalysis
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Enzyme Saturation Point
Enzyme Saturation Point
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Enzyme Inhibitors
Enzyme Inhibitors
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Competitive Inhibitor
Competitive Inhibitor
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Salt Concentration's Effect on Enzymes
Salt Concentration's Effect on Enzymes
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Enzymes increase reaction rates by...
Enzymes increase reaction rates by...
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Denaturation
Denaturation
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Optimum Temperature
Optimum Temperature
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Optimum pH
Optimum pH
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Enzyme-Substrate Complex
Enzyme-Substrate Complex
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Specificity of Enzymes
Specificity of Enzymes
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How do enzymes speed up reactions?
How do enzymes speed up reactions?
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Binding of Enzyme and Substrate
Binding of Enzyme and Substrate
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Transition State
Transition State
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Product
Product
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Catalysis
Catalysis
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What are enzymes made of?
What are enzymes made of?
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Denaturation of Enzymes
Denaturation of Enzymes
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Study Notes
Enzymes: Biological Catalysts
- Enzymes are protein molecules with catalytic activity, crucial for metabolic processes and chemical reactions in cells.
- Enzymes react with a molecule (substrate) and convert it into a different molecule (product).
- Enzyme regulation is vital for clinical diagnosis.
- Ribozymes are RNA catalysts.
- Enzymes are present in all tissues and fluids. Intracellular enzymes catalyze metabolic pathways; membrane-bound enzymes respond to cellular signals; circulatory enzymes regulate blood clotting, etc.
Enzyme Structure
- Enzymes are linear chains of amino acids forming a 3D structure.
- Amino acid sequence determines the enzyme's structure and catalytic activity.
- Enzyme structure denatures, and activity is lost with heat.
- Enzymes are large molecules, much larger than their substrates, ranging from 62 to 2,500+ amino acid residues.
- Only a small part (active site) of the enzyme is involved in catalysis, consisting of the catalytic and binding sites.
- Some ribozymes are RNA biological catalysts combined with proteins.
Enzyme Classification
- Enzymes are classified into six functional classes according to the type of reaction they catalyze (International Union of Biochemists - IUB).
- Oxidoreductases: Catalyze oxidation-reduction reactions (e.g., pyruvate dehydrogenase).
- Transferases: Transfer chemical groups between molecules (e.g., transaminase).
- Hydrolases: Catalyze hydrolysis reactions (e.g., pepsin hydrolyzes peptide bonds in proteins).
- Lyases: Break bonds without the addition of water (e.g., aldolase).
- Isomerases: Catalyze the formation of isomers (e.g., phosphoglucomutase).
- Ligases: Join two molecules together (e.g., DNA ligase).
Cofactors
- Cofactors are non-protein components essential for enzyme function.
- The protein part of an enzyme is the apoenzyme.
- Enzyme + cofactor = holoenzyme.
- Cofactors can be metal ions or organic molecules (coenzymes).
Examples of Enzyme Action
- Beverages: Fermentation varies depending on the plant product and enzyme used (e.g., grapes, honey, hops, etc. for wine, beer).
- Food: Bread fermentation uses yeast and sugar to produce carbon dioxide gas, giving the bread its texture.
- Drug action: Drugs can inhibit or promote enzyme activity by affecting the active site.
Mechanism of Enzyme Action
- Collision theory: Molecules must collide with the correct orientation and sufficient energy (activation energy).
- Active site: Enzymes have a specific shape and functional groups for substrate binding.
- Enzyme-substrate complex: The enzyme and substrate bind weakly, but this interaction induces conformational changes.
- Induced fit model: The binding between enzyme and substrate strengthens with changes, with the active site adapting to fit.
- Catalysis Mechanisms: Enzymes use various mechanisms:
- Bond strain: The enzyme strains substrate bonds.
- Covalent catalysis: Covalent intermediates form between enzyme and substrate.
- Acid/base catalysis: Enzymes use amino acid side chains as acid or base catalysts.
- Orientation and proximity: Brings substrate groups together
- Two-step process: -Enzyme + substrate → enzyme-substrate complex -enzyme-substrate complex → product + enzyme
Factors Affecting Enzyme Activity
- Temperature: Optimal temperature increases activity, but extreme temperatures denature the enzyme.
- pH: Most enzymes have an optimal pH near neutrality, but some function in more extreme conditions. pH changes can affect amino acid charges (and thus enzyme activity).
- Substrate concentration: Low substrate concentration affects reaction rate, but high concentration leads to saturation, where reaction rate plateau.
- Inhibitors: Inhibitors can bind to the active site blocking substrate binding (competitive inhibitors) affecting enzyme activity.
- Salt concentration: Changes in salinity can affect protein folding and interactions, thus enzyme function.
Active Site
- The active site's amino acid residues are crucial for catalysis and substrate binding.
- Active site amino acids are not necessarily contiguous, but are properly positioned by 3D folding.
- Common active site residues include polar amino acids, aspartate, cysteine, glutamate, histidine, serine, and lysine.
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Description
This quiz explores the essential roles enzymes play within the human body, including their catalytic activities and the effects of various factors on their performance. Test your knowledge on enzyme functionality, substrates, and inhibitors while learning about the significance of enzymes in biological processes.
