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Enzymes: “Helper” Protein molecules

Learn about the crucial role of enzymes in living organisms and how they facilitate the flow of energy through life. Discover how enzymes are proteins that act as biological catalysts, speeding up reactions by breaking down or synthesizing molecules. Explore the importance of enzyme structure, their specific nature, and their ability to be reused. Understand the Lock & Key and Induced Fit models that explain enzyme-substrate interactions. Gain insights into the factors that affect enzyme activity, such as temperature and pH.

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Enzymes: “Helper” Protein molecules

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  1. Enzymes: “Helper” Protein molecules

  2. Flow of energy through life • Life is built on chemical reactions

  3. enzyme + enzyme + Nothing works without enzymes! • How important are enzymes? • all chemical reactions in living organisms require enzymes to work • building molecules • synthesis enzymes • breaking down molecules • digestive enzymes • enzymes speed up reactions • Biological catalysts We can’t live without enzymes!

  4. Enzymes are proteins • Each enzyme is the specific helper to a specific reaction • Must be the right shape for the job • Enzymes are named for the reaction they help • sucrase breaks down sucrose • proteases breakdown proteins • lipases breakdown lipids • DNA polymerase builds DNA Oh, I get it! They end in -ase

  5. active site Enzymes aren’t used up • Enzymes are not changed by the reaction • used only temporarily – like a taxi • re-used again for the same reaction with other molecules • very little enzyme needed to help in many reactions substrate product enzyme

  6. It’s shape that matters! • Lock & Key model • Induced Fit Model • shape of protein allows enzyme & substrate to fit

  7. Enzyme vocabulary • Enzyme • Biological catalyst: helper protein molecule • Substrate • molecule that enzymes work on • Products • what is produced in reaction. • Active site • part of enzyme that substrate molecule fits into

  8. What affects enzyme action • Correct protein structure • Temperature • pH (acids & bases)

  9. Order of amino acids • Wrong order = wrong shape = can’t do its job! foldedprotein chain ofamino acids DNA right shape! foldedprotein chain ofamino acids wrong shape! DNA

  10. Temperature • Effect on rates of enzyme activity • Optimum temperature • greatest number of collisions between enzyme & substrate • human enzymes • 35°- 40°C (body temp = 37°C) • Raise temperature (boiling) • denature protein = unfold = lose shape • Lower temperatures • molecules move slower • fewer collisions between enzyme & substrate

  11. 37° Temperature humanenzymes What’s happening here?! reaction rate temperature

  12. pH (Acids and Bases) • Effect on rates of enzyme activity • changes in pH changes protein shape • most human enzymes = pH 6-8 • depends on where in body • pepsin (stomach) = pH 3 • trypsin (small intestines) = pH 8

  13. pH stomachpepsin intestinestrypsin What’s happening here?! reaction rate 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH

  14. SHAPE! For enzymes…What matters?

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