2.1.4 Enzymes Flashcards
What are enzymes called?
Biological catalysts
Enzymes can be ___ or ___
Intracellular or extracellular
Structure of an enzyme
Active site which specific substrates bind to to create an enzyme-substrate complex
What can change the shape of an active site?
pH and temperature changes.
What is the lock and key hypothesis?
The idea that the enzyme has a fixed shape and only the right substrate will fit into the active site.
What is the induced fit hypothesis?
When the substrate molecule fits into the enzymes active site, the active site undergoes a conformational change in its shape fit itself around the substrate molecule, enabling a tighter fit.
Factors that affect enzyme activity?
-pH
-Temperature
-Enzyme concentration
-Substrate concentration
What is the affect of a pH on enzyme activity?
All enzymes have an optimum pH which they work best at. At extreme pH’s enzymes are denatured. Below and above an enzymes optimum pH, solutions with an excess of H+ ions and OH- ions can cause these bonds to brisk so enzyme substrate complexes form les easily.
What can we use to investigate the effect of different pH’s on enzyme activity?
Buffer soloutions
What is the affect of low temperature on enzyme activity?
Lower temperatures prevent reactions from proceeding or slow the down as the molecules will have less kinetic energy. Less kinetic energy results in fewer successful collisions so fewer enzyme substrate complexes. Substrates and enzymes will also collide with less energy.
What is the affect of high temperatures on enzyme activity?
Higher temperatures causes molecules to have more kinetic energy so they will move faster and increase the success of collisions so result in more enzyme substrate complexes.
What is the temperature coefficent?
Measure of how much reaction rate increases with a 10 degree temp increase.
What is the affect of enzyme concentration on enzyme activity?
The higher the enzyme concentration, the greater the number of actor sites available for enzyme substrate complex formation. As long as there are sufficient substrates available, the rate of reaction increases.
What is the affect of substrate concentration on enzyme activity?
The greater the substrate concentration, the higher the rate of reaction. As the number of substrate molecules increases,the likelihood of enzyme substrate compels formation increases. If all active sites are saturated,any further increase in substrate concentration will not increase reaction rate.
What is activation energy?
the minimum amount of energy needed to start a chemical reaction
How do enzymes reduce the amount of activation energy needed?
They reduce the stability of bonds in the reactants so the reaction increases.
What are the two types of reversible inhibitors?
Competitive and non competitive.
What is a competitive inhibitor?
Have a similar shape to a substrate molecule and so therefore compete with the substrate for the active site.
What is a non competitive inhibitor?
Binds to the enzyme at an alternative site (not the active site) which alters the shape of the active site so prevents the substrate from binding with it.
What is the affect of inhibitors on enzyme activity?
They slow enzyme activity down or stop it.
What are non reversible inhibirors?
Occupy the active site forever, permenant.
Covalent bonds form between the enzyme and the inhibitor.
What is the result of a non reversible inhibitor?
The enzyme will be completely inactivated.
Non reversible inhibitors can also be called ____
Metabolic poisions.
What is a co-factor?
An inorganic ion or nonprotein organic molecule at the active site that makes the enzyme active.
