Unit 5 - Enzymes

5.1 Enzymes - What are Enzymes?

• Enzymes are catalysts, speeding up chemical reactions without being consumed.
• Enzymes are proteins.
• They are essential for all living organisms, regulating metabolic reactions at a sustainable rate.
• Without enzymes, digestion of a meal could take 2-3 weeks instead of 4 hours.

5.1 Enzymes - How Do Enzymes Work?

• Enzymes are specific to a particular substrate (molecule in a reaction).
• Enzyme shape complements the substrate's shape for efficient binding.
• The product of the reaction is formed from the substrate(s) and released.

5.2 Enzyme Investigations - Investigating the Effect of Temperature on Amylase

• Starch solution is heated to a set temperature.
• Iodine solution is added to wells on a spotting tile to test for starch presence.
• Amylase is mixed with starch, creating a solution.
• A new well of iodine is added each minute to monitor the reaction.
• The reaction continues until the iodine stops turning blue-black, a sign of the starch being fully broken down.

5.2 Enzyme Investigations - Investigating the Effect of pH on Amylase

• Single drops of iodine solution are placed in rows on a tile.
• A test tube is labelled with the pH to be tested.
• 2cm of amylase, 1cm of buffer solution, and 2cm of starch solution are added to the test tube.
• Start a stopwatch and mix using a pipette.
• After 10 seconds, a drop of the mixture is placed on a drop of iodine.
• This process is repeated every 10 seconds until the iodine remains orange-brown, showing the rate of starch digestion.
• The experiment is repeated for various pH values. A quicker reaction time indicates better enzyme activity at a specific pH.

5.3 Enzyme Action and Specificity

• Enzymes' active site is specific to a substrate(s).
• Enzymes and substrates collide randomly in solution.
• The enzyme-substrate complex forms when the substrate binds to the active site, allowing the reaction.
• Products are released, and the enzyme remains unchanged, ready for another reaction.

5.4 Enzymes and Temperature

• Enzymes are proteins with specific shapes held by bonds.
• Optimum temperature for human enzymes is 37°C.
• Higher temperatures can break bonds, causing denaturation and a loss of enzyme activity.
• Increasing temperatures initially increase enzyme activity because of more collisions, but at higher temperatures the increased activity decreases as the active site is deformed (denaturing).
• Low temperatures decrease enzyme activity by slowing molecule movement.

5.5 Enzymes and pH

• Enzymes have an optimum pH for maximum activity.
• The optimum pH varies depending on the enzyme's location in the body (e.g., stomach enzymes have a lower optimum pH).
• Extreme pH values can cause denaturation and loss of activity.

Explore the fascinating world of enzymes in this quiz covering their roles as catalysts, their structure as proteins, and their imperative functions in living organisms. Test your knowledge on how enzymes interact with substrates and the effects of temperature on enzyme activity, specifically amylase. Get ready to dive into the critical mechanisms that sustain life!