IB Biology - Unit 8 Revision

Which statement is true of most metabolic reactions?

• They occur in a sequence of small step catalysed by one enzyme
• They occur in one large step catalysed by many enzymes
• They occur in one large step catalysed by one enzyme
• They occur in a sequence of small step catalysed by many enzymes

What do metabolic pathways consist of?

• Neither chains nor cycles of reactions
• Chains of reactions
• Cycles of reactions
• Chains and/or cycles of reactions

What is the activation energy?

• The energy an enzyme has
• The energy required to start a reaction
• The energy a substrate has
• The energy required to open the active site

What is the effect of enzymes on the activation energy?

• It depends on the enzyme
• They lower it
• They increase it
• They have no effect on it

Where do competitive inhibitors bind to?

• An allosteric site on the enzyme
• An allosteric site of the substrate
• The active site of the enzyme
• The active site of the substrate

Where do non-competitive inhibitors bind to?

• An allosteric site on the enzyme
• The active site of the substrate
• The active site of the enzyme
• An allosteric site of the substrate

What are the two types of enzyme inhibitors?

• Fast & Slow
• Competitive & Non-competitive
• Active & Inactive
• Active & Non-active

Which statement is true about the graph for rate of reaction with a competitive inhibitor?

• The maximum rate of reaction is reached at higher substrate concentrations
• The rate of reaction is the same as for a non-competitive inhibitor
• The maximum rate of reaction is never reached
• The maximum rate of reaction is reached at lower substrate concentrations

Which statement is true about the graph for rate of reaction with a non-competitive inhibitor?

• The maximum rate of reaction is reached at lower substrate concentrations
• The maximum rate of reaction is reached at higher substrate concentrations
• The rate of reaction is the same as for a competitive inhibitor
• The maximum rate of reaction is never reached

Which of the following is the correct example of end-product inhibition?

• Threonine acts as a non-competitive inhibitor preventing a reaction with isoleucine
• Threonine acts as a competitive inhibitor preventing a reaction with isoleucine
• Isoleucine acts as a competitive inhibitor preventing a reaction with threonine
• Isoleucine acts as a non-competitive inhibitor preventing a reaction with threonine