Biochemistry Chapter 1: Enzymes
49 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are enzymes?

Biological catalysts that speed up biochemical reactions in living cells.

What is a characteristic of enzymes?

  • They are only found in animal cells.
  • They are consumed in biochemical reactions.
  • They speed up reactions without being changed. (correct)
  • They can catalyze any type of reaction.
  • Which of the following is an example of a biochemical pathway?

  • Photosynthesis
  • Glycolysis (correct)
  • Fermentation
  • Cellular respiration
  • Enzymes are found in both bacterial and animal cells.

    <p>True</p> Signup and view all the answers

    What is an apoenzyme?

    <p>The protein part of a conjugated enzyme.</p> Signup and view all the answers

    A complete active enzyme system containing one or more cofactors is called a ______.

    <p>holoenzyme</p> Signup and view all the answers

    What are the two distinct types of proteins mentioned?

    <p>Fibrous and globular</p> Signup and view all the answers

    What is the primary structure of a protein?

    <p>A sequence of amino acids linked by peptide bonds.</p> Signup and view all the answers

    Most enzymes are fibrous proteins.

    <p>False</p> Signup and view all the answers

    What distinguishes globular proteins from fibrous proteins?

    <p>Globular proteins are tightly folded into spherical shapes.</p> Signup and view all the answers

    What is the molecular weight of proteins expressed in?

    <p>Daltons</p> Signup and view all the answers

    Which of these statements correctly describes the role of enzymes in living organisms?

    <p>Enzymes perform functions that depend on their shape and structure.</p> Signup and view all the answers

    What elements are typically included in the composition of an enzyme?

    <p>Metal ions and coenzymes</p> Signup and view all the answers

    What is the significance of peptide bonds in proteins?

    <p>They link amino acids together.</p> Signup and view all the answers

    How many common amino acids are generally found in proteins?

    <p>22</p> Signup and view all the answers

    Which protein structure is characterized by coiling into an alpha helix?

    <p>Secondary structure</p> Signup and view all the answers

    What happens to proteins when the need arises for energy or raw materials?

    <p>They are broken down.</p> Signup and view all the answers

    What role do enzymes play in biochemical reactions?

    <p>They increase the reaction rate without changing themselves.</p> Signup and view all the answers

    Which of the following statements accurately describes enzyme specificity?

    <p>Each enzyme is specific to a single substrate or reaction.</p> Signup and view all the answers

    What is the main distinction between an apoenzyme and a cofactor?

    <p>Apoenzymes are the protein component, while cofactors are the non-protein component.</p> Signup and view all the answers

    Which of the following reactions illustrates the function of enzymes in metabolic processes?

    <p>The conversion of glucose to pyruvate during glycolysis.</p> Signup and view all the answers

    What is a holoenzyme?

    <p>A complete and active enzyme system with cofactors.</p> Signup and view all the answers

    How do enzymes affect the activation energy of biochemical reactions?

    <p>They stabilize the transition state and decrease activation energy.</p> Signup and view all the answers

    Which of the following is NOT a function of enzymes?

    <p>Maintaining structural integrity of cells.</p> Signup and view all the answers

    In what type of environments do enzymes typically operate optimally?

    <p>In controlled conditions with specific pH and temperature ranges.</p> Signup and view all the answers

    What distinguishes oligomeric enzymes from monomeric enzymes?

    <p>Oligomeric enzymes are composed of two or more polypeptide chains.</p> Signup and view all the answers

    Which statement is true regarding metal ions in enzymes?

    <p>Metal-activated enzymes retain metal in equilibrium with surface binding groups.</p> Signup and view all the answers

    What is a characteristic feature of carboxypeptidase A?

    <p>It is a metalloenzyme associated with a metal ion.</p> Signup and view all the answers

    How does feedback inhibition regulate the activity of oligomeric enzymes?

    <p>By affecting the subunits interaction and overall enzyme activity.</p> Signup and view all the answers

    What type of enzyme is classified as a dimeric enzyme?

    <p>An enzyme with two identical or different subunits.</p> Signup and view all the answers

    What is the molecular weight threshold for oligomeric enzymes?

    <p>More than 35,000 Daltons.</p> Signup and view all the answers

    Which of the following enzymes is commonly known to be oligomeric?

    <p>Enolase</p> Signup and view all the answers

    What are protomers in the context of oligomeric enzymes?

    <p>Identical subunits in a oligomeric enzyme.</p> Signup and view all the answers

    What is the significance of quaternary structures in biomolecules?

    <p>They can improve functional roles through assembly.</p> Signup and view all the answers

    What type of enzymes consist of a single polypeptide chain?

    <p>Monomeric enzymes</p> Signup and view all the answers

    Why are proteolytic enzymes produced in an inactive form?

    <p>To prevent damage to cellular proteins.</p> Signup and view all the answers

    Which of the following describes a characteristic of quaternary structures in biological systems?

    <p>They may contain multiple different tertiary structural units.</p> Signup and view all the answers

    What happens to a monomer when it assembles into a quaternary structure?

    <p>It may undergo conformational changes to establish contacts.</p> Signup and view all the answers

    What is the approximate molecular weight range for monomeric enzymes?

    <p>13,000 - 35,000 Daltons</p> Signup and view all the answers

    What process does chymotrypsinogen undergo to become active?

    <p>It is activated by trypsin.</p> Signup and view all the answers

    How do hydrophobic sections of monomers behave in the presence of water?

    <p>They aggregate to minimize exposure to water.</p> Signup and view all the answers

    What best describes the active site of an enzyme?

    <p>A complex 3-dimensional structure that binds the substrate.</p> Signup and view all the answers

    How many amino acid residues typically comprise the catalytic groups of an enzyme's active site?

    <p>12</p> Signup and view all the answers

    Which of the following forces is primarily involved in substrate binding at the active site of an enzyme?

    <p>Hydrogen bonds</p> Signup and view all the answers

    What role does the tertiary structure of an enzyme play in its active site?

    <p>It brings amino acids close together in three-dimensional space.</p> Signup and view all the answers

    What is the typical strength range of the free energy of interaction between an enzyme and its substrate?

    <p>-12 to -36 kJ/mole</p> Signup and view all the answers

    In the context of enzymes, what is a catalytic site?

    <p>A region involved with catalysis within the enzyme.</p> Signup and view all the answers

    Where do the residues that constitute the active site typically occur in an enzyme?

    <p>On connecting loops between helices and sheets.</p> Signup and view all the answers

    What typically allows for the specificity of an enzyme towards its substrate?

    <p>The shape and charge compatibility of the active site.</p> Signup and view all the answers

    Study Notes

    Enzymes Overview

    • Enzymes are primarily proteins that act as biological catalysts, accelerating biochemical reactions in living cells without changing themselves.
    • They increase reaction rates by a factor of 10^2 to 10^8.
    • Enzymes are involved in numerous metabolic processes, such as glycolysis, where glucose transforms into pyruvate.
    • Enzymes are essential for reading genetic information from DNA and synthesizing non-protein cell components.
    • Roughly 2,000 enzymes exist in bacterial cells (e.g., Escherichia coli) and about 10,000 in eukaryotic animal cells.
    • Enzymes have diverse applications in healthcare, food production, and various industries due to their specificity.

    Structure of Enzymes

    • Enzymes are constituted either solely of proteins or in conjunction with non-protein molecules or metal ions.
    • The protein component is termed apoenzyme, and the non-protein part is a cofactor, which can be inorganic (metal ion) or organic (coenzyme).
    • A complete and active enzyme system is referred to as a holoenzyme, derived from the combination of an apoenzyme and its cofactor.

    Protein Structure and Function

    • Most enzymes are proteins, necessitating an understanding of protein structure for enzyme comprehension.
    • Proteins are large macromolecules with molecular weights exceeding several thousand Daltons, constituting more than half the dry weight of cells.
    • Two main protein types exist:
      • Fibrous Proteins: Insoluble in water; provide structural support (e.g., α-keratin in hair, collagen in skin).
      • Globular Proteins: Generally soluble and compact, playing functional roles (most enzymes fall into this category).
    • Each protein has a specific function tied to its structure and shape, differentiating them from polysaccharides and lipids which primarily serve energy storage.
    • Proteins can be degraded for energy or building materials as needed.

    Protein Structure Levels

    • Primary Structure: Sequential arrangement of amino acids connected by peptide bonds, including disulfide bonds.
    • Secondary Structure: Polypeptides can form structures like α-helices, contributing to overall protein functionality.

    Enzymes Overview

    • Enzymes are primarily proteins that act as biological catalysts, accelerating biochemical reactions in living cells.
    • They significantly increase reaction rates, often by 10^2 to 10^8 times.
    • Enzymes are crucial for metabolic processes, such as glycolysis, which converts glucose to pyruvate.
    • Over 2000 enzymes can be found in bacteria, while eukaryotic animal cells contain around 10,000 different enzymes.
    • Enzymes are utilized in various applications, including hospital diagnostics, food manufacturing, and meat tenderization.

    Enzyme Structure

    • Enzymes are categorized as either proteins alone or as proteins combined with cofactors (organic or inorganic).
    • The protein portion is called an apoenzyme, while the complete enzyme structure with cofactors is termed a holoenzyme.
    • Simple enzymes consist solely of proteins, while conjugated enzymes require additional molecules for activity.

    Protein Structure

    • Proteins are macromolecules with molecular weights typically over several thousand Daltons, constituting over 50% of cellular dry weight.
    • Types include fibrous proteins (e.g., keratin, collagen) and globular proteins, the latter being more prevalent among enzymes.
    • Proteins serve specific functions based on their structure but can also provide energy or raw materials when necessary.

    Levels of Protein Structure

    • Primary structure involves the sequence of amino acids linked by peptide bonds.
    • Secondary structures include formations like α-helices and β-sheets arising from hydrogen bonding.
    • Tertiary structure represents the 3D folding of a single polypeptide, affecting functionality.
    • Quaternary structure involves multiple polypeptide chains (subunits) and can form complex functional assemblies.

    Types of Enzymes

    • Monomeric enzymes consist of a single polypeptide chain, found predominantly in hydrolytic reactions (e.g., trypsin, chymotrypsin).
    • Oligomeric enzymes contain two or more polypeptide chains (subunits), can be dimers or tetramers, and generally possess a higher molecular weight than monomeric enzymes.
    • Oligomeric enzymes often demonstrate cooperative properties, which are absent in isolated units, and are regulated by feedback inhibition.

    Cofactors

    • Cofactors are necessary small molecules or ions that assist enzyme function.
    • Metal ions play crucial roles, leading to classifications such as metalloenzymes (tightly bound metal) and metal-activated enzymes (looser binding).

    Active Site Features

    • The active site is the enzyme region that binds substrates and contains catalytic amino acids, typically around 12.
    • Enzymes are large compared to substrates; only a small portion is directly involved in catalysis.
    • Active sites form intricate 3D pockets designed for substrate interaction.
    • Weak interactions (e.g., electrostatic, hydrogen bonds) facilitate substrate binding within the active site, compared to the strength of covalent bonds.

    Sites Within Enzymes

    • Two key functional sites in enzymes are identified:
      • Catalytic site: Involved in the catalytic process.
      • Regulatory site: Modulates enzyme activity and interaction (not detailed in the text provided).

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Enzyme Study Guide PDF

    Description

    This quiz covers Chapter 1 on the structure and function of enzymes. It explores the role of enzymes as biological catalysts that significantly increase the rate of biochemical reactions. Test your understanding of enzymes and their importance in cellular processes.

    More Like This

    Enzyme Structure and Function Quiz
    10 questions

    Enzyme Structure and Function Quiz

    AppreciatedSerpentine4950 avatar
    AppreciatedSerpentine4950
    Enzyme Structure and Function
    10 questions

    Enzyme Structure and Function

    InspirationalSanctuary9859 avatar
    InspirationalSanctuary9859
    Introduction to Enzymes
    13 questions

    Introduction to Enzymes

    DedicatedSard3010 avatar
    DedicatedSard3010
    Enzymes and Catalysts Quiz
    18 questions

    Enzymes and Catalysts Quiz

    MesmerizingPerception5366 avatar
    MesmerizingPerception5366
    Use Quizgecko on...
    Browser
    Browser