Factors Affecting Enzyme Activity Flashcards
How can you measure enzyme activity?
Measure how fast the product is made.
Measure how fast the substrate is broken down.
What can affect enzyme activity?
Temperature.
pH.
Substrate concentration.
Enzyme concentration.
How does temperature effect the rate of enzyme-controlled reactions?
Increasing temperature increases the rate of reaction. More heat means more kinetic energy, so molecules move faster. This makes the substrate molecules more likely to collide with the enzyme’s active sites. The energy of these collisions also increases, which means each collision is more likely to result in a reaction.
What happens if the temperature gets too high?
The reaction stops. The rise in temperature makes the enzyme’s molecules vibrate more.
What happens when the vibrations get too strong?
The vibration causes some of the bonds that hold the enzyme in shape break. The active site changes shape and the enzyme and substrate no longer fit together.
What is the enzyme said to be when out no longer functions as a catalyst.
Denatured.
What is the temperature called that the rate of reaction is at the highest?
Optimum temperature.
What happens above and below the optimum pH?
The H+ and OH- ions found in acids and alkalis can disrupt the ionic bonds and hydrogen bonds that hold the enzyme’s structure in place. The enzyme becomes denatured, and the active site changes shape.
How does substrate concentration effect the rate of reaction?
The higher the substrate concentration, the faster the reaction. More substrate molecules means a collision between substrate and enzyme is more likely, and so more active sites will be occupied.
What is the saturation point?
When there are too many substrate molecules, as all the active sites are full, adding more makes no difference.
How does enzyme concentration effect the rate of reaction?
The more enzyme molecules there are in a solution the more likely a substrate is to bind. Increasing enzyme concentration increases the rate of reaction.
What happens if the amount of substrate is limited?
There comes a point when there are too many enzyme molecules and no more substrate is available, so adding more enzyme makes no difference.
What are enzyme inhibitors?
Molecules that prevent enzyme activity by binding to the enzyme that they inhibit.
What types of inhibitors are there?
Competitive Inhibitors.
Non-competitive Inhibitors.
What do competitive inhibitors do?
They have a similar shape to the substrate molecule, so they compete for the active site. When they bind to the active site no reaction takes place and they block it soo no substrate molecules can fit in. Increasing the concentration of substrate will make in less likely for a competitive inhibitor to bind.
