B3 - Enzymes Flashcards
What are enzymes?
Catalyst produced by living things
What is a catalyst?
A substance that Increases the rate of reaction without being changed or used up in a reaction
Why do the chemical reaction going on inside living things need to be careful controlled?
To get the right amount of substances.
How can you make a reaction happen more quickly?
By raising the temperature. This would speed up the useful reaction as well as the unwanted ones.
How do living things reduce the need for high temperatures in reaction?
They produce enzymes that work as biological catalyst.
We only have enzymes to speed up useful chemical reactions in the body.
Name one reaction, from plants, that needs enzymes?
Photosynthesis
What changes in a chemical reaction?
The substrate is the molecule changed in the reaction.
Chemical reaction involve things being split apart then joined together.
What is an active site on a enzyme?
The part where it joins onto it’s substrate to catalyse the reaction.
Enzymes usually only work with one substrate, they are said to have what?
A high specificity for their substrate.
Why do enzymes have high specificity?
For the enzyme to work the substrate has to fit into the active site.
If the substrate shape doesn’t match the active site shape then the reaction won’t be canalised
What is the lock and key model?
It describes how the substrate fits into the enzyme like a key fits into a lock.
List three things that can effect the rate of reaction.
Temperature
pH
Substrate concentration.
Changing the temperature changes, what?
The rate of an enzymes catalysed reaction
Why does a higher temperature increase the rate of reaction?
The enzymes and substrates have more energy so they move about more and are more likely to collide and form enzyme substrate complexes.
What happens to the reaction when it gets too hot?
Some of the bonds that hold the enzyme together break, changing the shape of the enzyme’s active site, so the substrate won’t fit anymore.
