Enzymes

View mindmap
  • The Inside Story - Enzymes
    • ENZYMES are CATALYSTS produced by LIVING THINGS
      • Enzymes make CHEMICAL REACTIONS work
        • You can make a reaction happen faster by RAISING THE TEMPERATURE. This would speed up useful and unwanted reactions.
          • There's also a LIMIT to how far you can raise the temperature inside a living creature before its CELLS start getting DAMAGED
          • Living things produce ENZYMES that act as BIOLOGICAL CATALYSTS. Enzymes reduce the need for high temperatures and we ONLY have enzymes to speed up the USEFUL CHEMICAL REACTIONS in the body.
            • CATALYST -  A subtance which INCREASES the speed of a reaction, without being CHANGED or USED UP in the reaction.
            • Enzymes are all LARGE PROTEINS.
              • Large proteins are made up of CHAINS of AMINO ACIDS. They are folded into UNIQUE SHAPES, which enzymes need to do their jobs.
                • Enzymes have SPECIAL SHAPES so they can CATALYSE REACTIONS
                  • The Inside Story - Enzymes
                    • ENZYMES are CATALYSTS produced by LIVING THINGS
                      • Enzymes make CHEMICAL REACTIONS work
                        • You can make a reaction happen faster by RAISING THE TEMPERATURE. This would speed up useful and unwanted reactions.
                          • There's also a LIMIT to how far you can raise the temperature inside a living creature before its CELLS start getting DAMAGED
                          • Living things produce ENZYMES that act as BIOLOGICAL CATALYSTS. Enzymes reduce the need for high temperatures and we ONLY have enzymes to speed up the USEFUL CHEMICAL REACTIONS in the body.
                            • CATALYST -  A subtance which INCREASES the speed of a reaction, without being CHANGED or USED UP in the reaction.
                            • Enzymes are all LARGE PROTEINS.
                              • Large proteins are made up of CHAINS of AMINO ACIDS. They are folded into UNIQUE SHAPES, which enzymes need to do their jobs.
                                • Enzymes have SPECIAL SHAPES so they can CATALYSE REACTIONS
                                  • EVERY enzyme has an ACTIVE SITE with a unique shape that FITS onto the substance involved in a reaction.
                                    • Enzymes usually only catalyse ONE SPECIFIC REACTION.
                                      • Because for the enzyme to work, the substrate has to FIT into its active site. If it doesn't MATCH the enzyme's active site, then the reaction WON'T be catalysed.
                                        • The LOCK AND KEY MODEL shows a simpler version of how it works. In reality the active site CHANGES SHAPE as the substrate binds to it to get a TIGHTER FIT. This is called the INDUCED FIT model.
                    • ENZYMES need the RIGHT TEMPERATURE and pH
                      • Changing the TEMPERATURE changes the RATE of an enzyme-catalysed reaction.
                        • A higher temperature INCREASES the rate at first.
                        • If it gets TOO HOT, some of the BONDS holding the enzyme together BREAK. This changes the shape of the enzyme's ACTIVE SITE. So the substrate WON'T FIT any more. The enzyme is said to be DENATURED.
                        • All enzymes have an OPTIMUM TEMPERATURE that they work best at.
                          • The pH also effects enzymes. If it's too high or too low, it interferes with the BONDS holding the enzymes together. Thus, changing the SHAPE of the ACTIVE SITE and DENATURES the enzyme.
                            • All enzymes have an OPTIMUM pH that they work best at. Often it's NEUTRAL pH 7 but NOT ALWAYS - e.g. PEPSIN is an enzyme used to break down PROTEINS in the STOMACH. It works best at pH 2, which means it's well suited to the ACIDIC CONDITIONS there.
                              • Rate = 1000/time e.g. pH6, time taken was 90 seconds So rate = 1000/90 = 11 s-1
                                • If how much something changes over time, you calculate the rate of reaction by doing this = Amount changed over time/time taken
                    • Investigating the effect of pH on enzyme activity.
                      • ENZYMES need the RIGHT TEMPERATURE and pH
                        • Changing the TEMPERATURE changes the RATE of an enzyme-catalysed reaction.
                          • A higher temperature INCREASES the rate at first.
                          • If it gets TOO HOT, some of the BONDS holding the enzyme together BREAK. This changes the shape of the enzyme's ACTIVE SITE. So the substrate WON'T FIT any more. The enzyme is said to be DENATURED.
                          • All enzymes have an OPTIMUM TEMPERATURE that they work best at.
                            • The pH also effects enzymes. If it's too high or too low, it interferes with the BONDS holding the enzymes together. Thus, changing the SHAPE of the ACTIVE SITE and DENATURES the enzyme.
                              • All enzymes have an OPTIMUM pH that they work best at. Often it's NEUTRAL pH 7 but NOT ALWAYS - e.g. PEPSIN is an enzyme used to break down PROTEINS in the STOMACH. It works best at pH 2, which means it's well suited to the ACIDIC CONDITIONS there.
                                • Rate = 1000/time e.g. pH6, time taken was 90 seconds So rate = 1000/90 = 11 s-1
                                  • If how much something changes over time, you calculate the rate of reaction by doing this = Amount changed over time/time taken
                      • The emzyme AMYLASE catalyses the breakdown of STARCH to MALTOSE. It's easy to DETECT STARCH using IODINE SOLUTION - if starch is present, the iodine solution will change from BROWN-ORANGE to BLUE-BLACK.
                        • Put a DROP of iodine solution into every well of a SPOTTING TILE.
                          • Place a BUNSEN BURNER on a HEAT-PROOF MAT, and a TRIPOD and GAUZE over it. Put a beaker of WATER on top of the tripod and HEAT the water until 35 degrees C. Try to keep CONSTANT.
                            • Use a SYRINGE to add 1cm cubed of AMYLASE SOLUTION and BUFFER SOLUTION with a pH of 5 to a boiling tube. Use TEST TUBE HOLDERS, put the tube into the beaker of water and wait for 5 minutes.
                              • Use a DIFFERENT SYRINGE to add 5cm cubed of a STARCH SOLUTION to the boiling tube.
                                • MIX THE CONTENTS and start a STOP CLOCK.
                                  • Use CONTINUOUS SAMPLING to record HOW LONG it takes for the amylase to break down all the starch. To do this, use a dropping pipette to take a FRESH SAMPLE from the boiling tube EVERY 30 SECONDS and put a DROP into a WELL. When the iodine solution REMAINS BROWN-ORANGE, starch is no longer present.
                                    • REPEAT with different pH VALUE buffer solutions to see how it AFFECTS the time taken for the starch to be broken down. CONTROL ANY VARIABLES e.g. concentration and volume of amylase solution.
                    • Rate of reaction
                    • Enzymes are needed in the digestion system to catalyse the BREAKDOWN of different food molecules.
                    • Digestive enzymes break down BIG MOLECULES
                      • Starch, proteins, and fats have to be broken down because they are too big to pass through the walls of the digestive system. They are broken down into smaller, SOLUBLE molecules like sugars, amino acids and fatty acids, allowing them to be absorbed into the bloodstream.
                        • CARBOHYDRASES(like amylase) convert CARBOHYDRATES(like starch) into SIMPLE SUGARS. Amylase found in SALIVARY GLANDS, PANCREAS, and the SMALL INTESTINE.
                        • PROTEASES- Convert PROTEINS into AMINO ACIDS. Made in the STOMACH, the PANCREAS and the SMALL INTESTINE.
                        • LIPASES - Convert LIPIDS(fats and oils) into GLYCEROL AND FATTY ACIDS. Made in the PANCREAS and the SMALL INTESTINE.
                  • EVERY enzyme has an ACTIVE SITE with a unique shape that FITS onto the substance involved in a reaction.
                    • Enzymes usually only catalyse ONE SPECIFIC REACTION.
                      • Because for the enzyme to work, the substrate has to FIT into its active site. If it doesn't MATCH the enzyme's active site, then the reaction WON'T be catalysed.
                        • The LOCK AND KEY MODEL shows a simpler version of how it works. In reality the active site CHANGES SHAPE as the substrate binds to it to get a TIGHTER FIT. This is called the INDUCED FIT model.
    • Investigating the effect of pH on enzyme activity.
      • The emzyme AMYLASE catalyses the breakdown of STARCH to MALTOSE. It's easy to DETECT STARCH using IODINE SOLUTION - if starch is present, the iodine solution will change from BROWN-ORANGE to BLUE-BLACK.
        • Put a DROP of iodine solution into every well of a SPOTTING TILE.
          • Place a BUNSEN BURNER on a HEAT-PROOF MAT, and a TRIPOD and GAUZE over it. Put a beaker of WATER on top of the tripod and HEAT the water until 35 degrees C. Try to keep CONSTANT.
            • Use a SYRINGE to add 1cm cubed of AMYLASE SOLUTION and BUFFER SOLUTION with a pH of 5 to a boiling tube. Use TEST TUBE HOLDERS, put the tube into the beaker of water and wait for 5 minutes.
              • Use a DIFFERENT SYRINGE to add 5cm cubed of a STARCH SOLUTION to the boiling tube.
                • MIX THE CONTENTS and start a STOP CLOCK.
                  • Use CONTINUOUS SAMPLING to record HOW LONG it takes for the amylase to break down all the starch. To do this, use a dropping pipette to take a FRESH SAMPLE from the boiling tube EVERY 30 SECONDS and put a DROP into a WELL. When the iodine solution REMAINS BROWN-ORANGE, starch is no longer present.
                    • REPEAT with different pH VALUE buffer solutions to see how it AFFECTS the time taken for the starch to be broken down. CONTROL ANY VARIABLES e.g. concentration and volume of amylase solution.
    • Rate of reaction
    • Enzymes are needed in the digestion system to catalyse the BREAKDOWN of different food molecules.
    • Digestive enzymes break down BIG MOLECULES
      • Starch, proteins, and fats have to be broken down because they are too big to pass through the walls of the digestive system. They are broken down into smaller, SOLUBLE molecules like sugars, amino acids and fatty acids, allowing them to be absorbed into the bloodstream.
        • CARBOHYDRASES(like amylase) convert CARBOHYDRATES(like starch) into SIMPLE SUGARS. Amylase found in SALIVARY GLANDS, PANCREAS, and the SMALL INTESTINE.
        • PROTEASES- Convert PROTEINS into AMINO ACIDS. Made in the STOMACH, the PANCREAS and the SMALL INTESTINE.
        • LIPASES - Convert LIPIDS(fats and oils) into GLYCEROL AND FATTY ACIDS. Made in the PANCREAS and the SMALL INTESTINE.

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Enzymes and digestion resources »