Enzymes Flashcards
What are enzymes?
Enzymes are biological catalysts- protein molecules that speed up chemical reactions.
Where does the catalyse chemical reactions take place?
In living cells.
Name three catalyse chemical reactions.
- Respiration.
- Photosynthesis.
- Protein synthesis.
What do active sites do, in an enzyme?
Enzymes have active sites that substrate molecules (the substances involved in the chemical reaction) fit into when a reaction happens.
Why do active sites have to be a specific shape?
The active site has to be the right shape for the substrate - a particular type of enzyme will only work with one or smaller number of substrates.
What is the ‘lock and key’ in an enzyme?
The mechanism involved in the chemical reaction, is called the ‘lock and key’ mechanism. Just as a lock will only accept one key, an enzyme will only accept one substrate.
What happens to enzyme reactions if the temperature is low?
The enzymes reactions slow down.
What happens to enzyme reactions if the temperature is high?
They speed up as the temperature rises until an optimum temperature is reached. After this point, the reaction will slow down and eventually stop.
When do enzymes work fastest?
Different enzymes work best at different pH values, their optimum pH. Many enzymes work fastest in neutral conditions. Making the solution more acidic or alkaline will slow the reaction down. At extremes of pH, the reaction will stop altogether.
How are enzymes used in the stomach adapted?
Enzymes have been adapted to work faster in unusual pH conditions. For example; stomach enzymes have an optimum pH of 2, which is very acidic.
