3.1 Enzyme Structure

• What are enzymes and their biological role?

  Biological catalysts that speed up reactions
• Enzymes are consumed during chemical reactions.

  False
• Cofactors can be organic (coenzymes) or inorganic ions
• What is the role of cofactors in enzymes?

  Assist in substrate binding
• The active site of an enzyme is located on the apoenzyme.

  True
• The protein component of an enzyme that provides the active site is called the apoenzyme
• What is the fully functional form of an enzyme called?

  Holoenzyme
• The enzyme-substrate complex facilitates the chemical reaction.

  True
• The active site lowers the activation energy
• What are allosteric sites on enzymes and what do they bind to?

  Regulatory molecules
• Allosteric inhibitors increase enzyme activity.

  False
• Enzymes are biological catalysts that speed up chemical reactions without being consumed
• The apoenzyme is the protein component of an enzyme that provides the active site
• Match the enzyme component with its type:

  Apoenzyme ↔️ Protein

  Cofactor ↔️ Non-protein
• The active site of an enzyme is complementary in shape and charge to the substrate.


  True
• Allosteric regulation is crucial for maintaining metabolic homeostasis.


  True
• Order the levels of protein structure from simplest to most complex:

  1️⃣ Primary

  2️⃣ Secondary

  3️⃣ Tertiary

  4️⃣ Quaternary
• Match the enzyme class with its function:

  Hydrolases ↔️ Hydrolyze chemical bonds

  Ligases ↔️ Join molecules using ATP

  Isomerases ↔️ Rearrange molecules

  Transferases ↔️ Transfer functional groups
• The induced-fit model enhances reaction specificity and catalytic efficiency.

  True
• Enzymes lower the activation energy
• What is the protein component of an enzyme called?

  Apoenzyme
• Apoenzymes provide the main protein structure of an enzyme.


  True
• Together, the apoenzyme and cofactor form a fully functional holoenzyme
• What are enzymes known as in biological terms?

  Biological catalysts
• A cofactor can be an organic molecule or an inorganic ion.


  True
• The active site of an enzyme binds to the substrate
• What is the active site of an enzyme complementary to in shape and charge?

  Substrate
• The active site ensures substrate specificity in enzymes.


  True
• Allosteric regulation allows cells to maintain metabolic homeostasis
• Why do enzymes lower the activation energy of reactions?

  To speed up reactions
• Enzymes lower the activation energy required for reactions.


  True
• A cofactor can be an organic molecule or an inorganic ion.


  True
• The active site on the apoenzyme binds to the substrate
• Allosteric sites are regions on enzymes, apart from the active site, where regulatory molecules can bind
• Protein folding involves arranging a protein chain into its unique, three-dimensional structure
• Incorrect protein folding can lead to misformed active sites and non-functional enzymes.


  True
• The induced-fit model suggests that the enzyme's shape changes to better accommodate the substrate