Unit 4: Enzymes

1. Unit 4: Enzymes

2. It is Just Chemistry…Really FAST Chemistry • All living things require chemistry to exist: • Photosynthesis (making sugars) • Glycolysis (breaking sugars) • Making ATP (energy units) • How long does it take for a chemical reaction to occur in a living thing? • 2.3 billion years • How long does the same reaction take with an enzyme? • Less than 1 second • Life CANNOT exist without enzymes 4.5 billion years

3. What is an Enzyme? • Biological catalysts a catalyst used in biochemistry • Catalyst a substance that speeds up a chemical reaction but is NOT affected by it • Never changed so it cannot be used up • Can reach a limit on how fast they can work • Enzymes are made of proteins • Few made from RNA (ribosome)

4. What do Enzymes do? • 10,000s of enzymes in a cell 1) Anabolic enzymes: • Build complex molecules • Photosynthesis changes CO2 into C6H12O6 (sugar) 2) Catabolic enzymes: • Break apart complex molecules • Glycolysis breaks sugar apart to make ATP (energy units) 3) Transformation enzymes: • Change one substance into another substance • Yeast add H+ to compounds to make alcohol

5. Enzyme Structures • Lock and Key Model: • Substrate substance the enzyme is designed for (Key) • Enzyme binds with substrates to combines them, break them apart, or change them (Lock) • Active site site in enzyme that is designed to match the shape of the substrate (Key Hole) • The Key (substrate) fits in the Lock (enzyme) by entering the Key Hole (active site) • Only if the Key (substrate) fits the Key Hole (active site) will the Lock (enzyme) work

6. Enzymatic Rates • Enzymes can be used over and over; only a few enzymes are needed to react with lots of substrate • How can we increase the reaction rate? • Add more enzymes (share the work) • Why does this rate stop increasing? • Enzyme can only work so fast • It takes time to do each reaction • All enzymes have a maximum efficiency

7. Enzymatic Rates: Temperature • What drives enzymatic rates? • Kinetic energy • Kinetic energy random movement in all atoms • Substrates and enzymes randomly move around and eventually join together • How can we increase kinetic energy in atoms? • Give them more energy by increasing temperature

8. Optimum Temperature • All enzyme reactions slow down at low temps and increase at higher temps • What happens when the temperature gets too high? • Enzyme stops working (denatures) • Protein bonds chemical bonds making holding the enzyme in a specific shape • High temps break these bonds; enzyme unfolds and cant work (denature) • Optimum temperature the temp. an enzymatic rate is highest without denaturing the enzyme • Fungi and plants 40 oC • Humans 37 oC • Some bacteria 90 oC

9. Optimum pH • pH can affect the peptide bonds of an enzyme too • Optimum pH the pH where the enzymatic rate is highest without denaturing the enzyme • Varies greatly in the body • Blood pH = 7.4 • Stomach pH = 2 • If you fix the pH and temp. of a denatured enzyme, can it be used again? • Sometimes. Some proteins can renature. Most proteins cannot.

10. The Properties of Enzymes • 5 Major Properties: • Enzymes are made of proteins • Enzymes catalyze one specific reaction • Enzymes, being catalysts, can be reused many times • Enzymes are influenced by temperatures (all have an optimum temperature) • Enzymes are influences by pH (all have an optimum pH)

11. Using Enzymes • Enzymes from living things can be used in production: • Medicine • Food • Fuel • Materials • General types: • Proteases break apart proteins • Lipases break apart fats • Amylases break down sugars • Cellulous break down cellulose (cell wall)

12. Making Medicine • Penicillin is an antibiotic that can kill many types of bacteria • Fungi Penicilliummakes it through fermentation (breaking down sugar without Oxygen) • Fermentation Process • Penicilliumadded to large vessel full of sugar and nutrients • Stirrer mixes up insides • Water-cooled jacket keeps vessel at 24 oC • Probes keep pH at 6.5 • After 6 days of this, penicillin can be drained from mixture • Cleaned and sent to hospitals

13. Homework • Study to Exam on Units 1-4 on 10/8 • Cell Projects due 10/11 • Quizlets for Units 3 and 4 • Homework papers on Unit 2, 3, and 4