Biochemistry: Enzymes and Their Function
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Questions and Answers

What is a key characteristic of enzymes compared to other chemical cofactors?

  • Enzymes change the results of reactions
  • Enzymes have a high degree of specialization (correct)
  • Enzymes are less efficient than other cofactors
  • Enzymes cannot perform reactions multiple times

What occurs to the enzyme at the end of a reaction?

  • It gets consumed in the reaction
  • It transforms into a different molecule
  • It is modified by the substrate
  • It returns to its original state (correct)

How do enzymes affect the speed of biochemical reactions?

  • They prevent reactions from occurring
  • They slow down the reaction significantly
  • They increase reaction speed by thousands to millions of times (correct)
  • They have a minimal effect on speed

What role does Mg2+ play in the interaction between ATP and glucose?

<p>It holds ATP in one area of the active site. (A)</p> Signup and view all the answers

What type of substances can an enzyme specifically act upon?

<p>Specific substrates that fit perfectly (B)</p> Signup and view all the answers

What occurs when glucose enters the active site of the enzyme?

<p>A conformational change in the enzyme takes place. (B)</p> Signup and view all the answers

Why are enzyme levels in blood clinically significant?

<p>They indicate the presence of specific diseases (B)</p> Signup and view all the answers

Which of the following statements about enzyme names is correct?

<p>Names can describe both substrate and function. (D)</p> Signup and view all the answers

What occurs during the breaking of glycosidic, ester, or peptide bonds?

<p>Hydroxyl and hydrogen atoms are added (D)</p> Signup and view all the answers

What is the classification number EC:(2.7.1.1) indicating for hexokinase?

<p>It transfers phosphate groups. (D)</p> Signup and view all the answers

How does an enzyme differ from a catalyst?

<p>Enzymes are specific to certain reactions and substrates (C)</p> Signup and view all the answers

What happens to the enzyme after glucose-6-phosphate is formed?

<p>It moves away due to reduced attraction to products. (C)</p> Signup and view all the answers

What effect does an increase in temperature have on an enzyme-catalyzed reaction at low temperatures?

<p>It increases the rate of the reaction. (B)</p> Signup and view all the answers

How does the active site of an enzyme lower the activation energy?

<p>By stabilizing the enzyme-substrate complex. (C)</p> Signup and view all the answers

Which of the following classes of enzymes is hexokinase categorized under?

<p>Transferases (D)</p> Signup and view all the answers

What happens to the reaction velocity as the concentration of products increases?

<p>The reaction velocity decreases. (B)</p> Signup and view all the answers

Which type of inhibition allows the enzyme activity to be regained after the inhibitor is removed?

<p>Reversible inhibition (A)</p> Signup and view all the answers

What is the outcome when glucose and ATP interact in the enzyme's active site?

<p>Glucose is converted into glucose-6-phosphate, and ADP is produced. (A)</p> Signup and view all the answers

What is the characteristic of competitive inhibitors?

<p>They compete with the substrate for the active site. (A)</p> Signup and view all the answers

What is the outcome when the temperature exceeds the optimum range for an enzyme?

<p>The enzyme is denatured. (A)</p> Signup and view all the answers

Which factor is responsible for decreasing the number of free enzymes available to react with substrate when a competitive inhibitor is present?

<p>The binding of the inhibitor to the enzyme. (A)</p> Signup and view all the answers

In which condition would reaction completion reach 100%?

<p>When products are removed as fast as they are formed. (C)</p> Signup and view all the answers

Which statement best describes noncompetitive inhibition?

<p>It can happen regardless of substrate concentration. (B)</p> Signup and view all the answers

What effect does increasing substrate concentration have on enzyme activity until saturation is reached?

<p>It initially increases enzyme activity. (D)</p> Signup and view all the answers

What is the term for the maximum velocity of an enzymatic reaction when the binding sites are fully saturated?

<p>Vmax (C)</p> Signup and view all the answers

How does increasing enzyme concentration affect the rate of reaction?

<p>It decreases competition for active sites. (B)</p> Signup and view all the answers

What role does vitamin C in lemon juice play when applied to sliced apples?

<p>It inhibits browning by changing pH. (D)</p> Signup and view all the answers

What condition describes an enzyme operating at peak activity?

<p>Steady state (C)</p> Signup and view all the answers

What is Km in the context of an enzymatic reaction?

<p>Half the maximum velocity of the enzyme (C)</p> Signup and view all the answers

What happens to the enzyme activity when all active sites are full?

<p>Enzyme activity stops increasing. (B)</p> Signup and view all the answers

Which factor is NOT typically a condition affecting enzyme activity?

<p>Volume of liquid in the reaction (C)</p> Signup and view all the answers

What is the mechanism of action of an irreversible inhibitor?

<p>It forms a covalent bond with an amino acid side chain in the active site. (A)</p> Signup and view all the answers

Which heavy metals are known to act as irreversible inhibitors?

<p>Silver, mercury, and lead. (A)</p> Signup and view all the answers

How does penicillin function as an antibiotic?

<p>It inhibits bacteria by binding to enzymes that synthesize cell walls. (C)</p> Signup and view all the answers

What is meant by the term saturation in enzyme kinetics?

<p>The maximum rate of reaction when enzyme active sites are fully occupied. (A)</p> Signup and view all the answers

Which factors are crucial for enzyme-substrate interactions?

<p>Conformation of proteins and positions of side chains. (A)</p> Signup and view all the answers

Why is understanding kinetic parameters important in biotechnology?

<p>To optimize enzyme reactions for faster substrate conversion. (C)</p> Signup and view all the answers

What happens to enzyme activity when an irreversible inhibitor is present?

<p>The enzyme becomes permanently inactive and cannot catalyze reactions. (C)</p> Signup and view all the answers

Which of the following best describes enzyme kinetics?

<p>It studies the influence of substrate concentration on product formation. (B)</p> Signup and view all the answers

Flashcards

What are enzymes?

Enzymes are biological catalysts that speed up chemical reactions without being consumed in the process.

How efficient are enzymes?

Enzymes are highly efficient, capable of catalyzing up to a million reactions per minute.

What is a substrate?

Each enzyme binds to a specific molecule called a substrate, like a lock and key.

How do enzymes differ from other catalysts?

Enzymes remain unchanged after a reaction, ready to catalyze another reaction.

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How do enzymes break down molecules?

Enzymes break down molecules by adding water, a process called hydrolysis.

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What is the role of enzymes in metabolism?

Enzymes play vital roles in metabolism, breaking down and building molecules.

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How are enzymes used in medical diagnostics?

Enzymes are used in medical diagnostics to detect specific conditions by measuring their levels in blood.

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How can you recognize an enzyme's name?

Many enzyme names end in '-ase,' signifying their catalytic nature.

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What do enzyme names often indicate?

Enzyme names often describe their function or substrate.

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Give examples of common enzyme names.

Common names are used for digestive enzymes, like pepsin and trypsin.

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How is the enzyme classification system organized?

Enzymes are classified using a four-digit EC number system based on their reaction type and function.

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What is an example of an EC number?

The EC number for Hexokinase, an enzyme responsible for glucose phosphorylation, is 2.7.1.1.

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How does substrate concentration affect enzyme activity?

Increasing substrate concentration usually boosts enzyme activity until it reaches a maximum level.

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What is the Michaelis constant (Km)?

Km is the substrate concentration at which the enzyme activity is half of its maximum velocity.

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What other factors affect enzyme activity?

Enzyme activity is also influenced by factors like temperature, pH, and time.

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What are inhibitors?

Inhibitors can interfere with enzyme activity, either temporarily or permanently.

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What do competitive inhibitors do?

Competitive inhibitors compete with the substrate for binding to the active site.

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How do noncompetitive inhibitors work?

Noncompetitive inhibitors bind to a different site on the enzyme, altering its shape and function.

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What are irreversible inhibitors?

Irreversible inhibitors permanently inactivate enzymes by forming strong bonds.

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What is an example of an enzyme inhibitor used in medicine?

Penicillin, an antibiotic, inhibits bacterial enzymes essential for cell wall synthesis.

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Why is understanding enzyme kinetics important in biotechnology?

Understanding enzyme kinetics is crucial for optimizing enzyme usage in biotechnology.

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How do kinetic parameters help in biotechnology?

Kinetic parameters like Km and Vmax guide the selection of enzymes for efficient substrate conversion.

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What are some applications of enzymes in industry?

Enzymes can be isolated and used in various industrial processes, such as food production and bioremediation.

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Give an example of enzyme application in detergents.

Enzymes are used in detergents to break down stains and improve cleaning efficiency.

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What is the role of enzymes in green chemistry?

Enzymes, acting as catalysts, can be used to synthesize new products in a more sustainable way.

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How are enzymes involved in bioremediation?

Enzymes contribute to various aspects of bioremediation, such as breaking down pollutants in the environment.

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Study Notes

Enzyme Function and Characteristics

  • Enzymes are highly efficient biological catalysts, operating at up to one million reactions per minute.
  • Enzymes bind specific substrates, exhibiting a high degree of specialization for substrates and reactions.
  • Enzymes return to their original state after reactions, distinguishing them from other chemical cofactors.

Reactions Catalyzed by Enzymes

  • Various enzymes catalyze the hydrolysis of glycosidic, ester, and peptide bonds in carbohydrates, lipids, and proteins.
  • The process typically involves breaking bonds through the addition of water, leading to chemical changes.

Roles of Enzymes

  • Enzymes are crucial in metabolism, diagnostics, and therapeutics within living organisms.
  • Enzyme concentration in blood can be diagnostically significant, aiding in medical diagnoses.
  • Example: Glucose interacts with ATP in enzyme active sites, with structural changes facilitating product release.

Enzyme Nomenclature

  • Most enzyme names end in "-ase"; sucrase, for instance, catalyzes sucrose hydrolysis.
  • Enzyme names often reflect their function or substrate; e.g., oxidases for oxidation reactions.
  • Common names are used for digestive enzymes, like pepsin and trypsin.

Enzyme Classification System

  • Enzymes are categorized using a four-digit EC number system, indicating class, subclass, and specific function.
  • Example: EC (2.7.1.1) for D-Hexose-6-Phosphotransferase (Hexokinase).

Factors Influencing Enzyme Activity

  • High substrate concentration increases enzyme activity until saturation occurs, reaching a maximum velocity (Vmax).
  • Km (Michaelis constant) represents substrate concentration at half of Vmax, indicating enzyme affinity for the substrate.
  • Enzyme activity is affected by temperature, pH, substrate concentration, enzyme concentration, product concentration, and time.

Inhibition of Enzyme Activity

  • Inhibitors can be reversible or irreversible, impacting enzyme functionality.
  • Reversible inhibitors can be competitive (compete for the active site) or noncompetitive (bind elsewhere).
  • Irreversible inhibitors, such as certain heavy metals and penicillin, permanently deactivate enzymes by forming covalent bonds.

Application in Medicine and Biotechnology

  • Antibiotics like penicillin inhibit bacterial enzymes vital for cell wall synthesis, halting bacterial infection.
  • Understanding enzyme kinetics is essential for optimizing enzymes in biotechnology applications.
  • Proper knowledge of kinetic parameters allows for the selection of enzymes that can maximize substrate conversion rates.

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Description

Explore the fascinating world of enzymes and their crucial role in biological reactions. This quiz delves into the specific characteristics of enzymes, including their unique substrates and how they enhance reaction speeds immensely. Test your understanding of the principles of enzymatic action and its significance in living organisms.

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