Course review
Review each learning objective in this topic, then open its concept explanation or question set.
Learning objective
• Enzymes are mostly protein biological catalysts, with some RNA examples • They work in small amounts and remain unchanged after catalysis
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Learning objective
• Metabolism is all enzyme-controlled chemical reactions in cells • Specific enzymes control which metabolic reactions occur and when
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Learning objective
• Anabolism builds complex molecules by condensation and requires energy • Catabolism breaks molecules by hydrolysis or oxidation and releases energy
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Learning objective
• Enzymes are usually globular proteins with a small active-site pocket • The active site binds substrate, forms an ES complex, and catalyses reaction
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Learning objective
• Substrate binding induces shape changes in both enzyme and substrate • Induced fit aligns catalytic groups and raises substrate toward transition state
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Learning objective
• Molecular motion brings substrates and active sites into collision • Higher kinetic energy increases successful active-site collisions
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Learning objective
• Active-site amino acid arrangement determines substrate specificity • Denaturation changes tertiary structure and active-site shape, not peptide bonds
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Learning objective
• Temperature increases rate to an optimum, then denaturation lowers activity • pH changes active-site bonding; substrate concentration rises to saturation plateau
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Learning objective
• Measure substrate loss or product formation per unit time • Use initial rate, replicates, controls, and graphs from amylase or catalase assays
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Learning objective
• Enzymes lower activation energy by providing an alternative pathway • They stabilize transition states but do not remove the energy barrier
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Learning objective
• Intracellular enzymes act in cytoplasm, organelles, or membranes • Extracellular enzymes are secreted and act outside cells, such as digestion enzymes
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Learning objective
• Exergonic metabolic reactions inevitably release some energy as heat • Endotherms use metabolic heat to maintain body temperature
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Learning objective
• Linear pathways run from substrate to product, such as glycolysis • Cyclical pathways regenerate an acceptor, such as Krebs and Calvin cycles
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Learning objective
• Non-competitive inhibitors bind away from the active site at allosteric sites • Binding changes enzyme shape and reduces activity despite substrate presence
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Learning objective
• Competitive inhibitors resemble the substrate and bind reversibly to active sites • Increasing substrate concentration can reduce their effect
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Learning objective
• End products inhibit earlier pathway enzymes when product accumulates • Feedback inhibition regulates pathway output, such as isoleucine synthesis
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Learning objective
• Mechanism-based inhibitors become irreversible after active-site reaction starts • Penicillin inhibits transpeptidase and prevents bacterial wall cross-linking
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