Enzymes Flashcards
Why do chemical reactions need to be carefully controlled in living things?
To get the right amounts of substances.
What is the problem with raising the temperature to speed up useful reactions?
Unwanted reactions will speed up too. There’s also a limit to how far you can raise the temperature inside a living creature before its cells start getting damaged.
What do living things produce that act as biological catalysts?
Enzymes.
What is good about enzymes relating to reactions?
Enzymes reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body.
What is a catalyst?
A catalyst is a substance which increases the speed of a reaction, without being changed or used up in the reaction.
What are all enzymes?
Large proteins and all proteins are made up of chains of amino acids. These chains are folded into unique shapes, which enzymes need to do their jobs.
Why do enzymes have special shapes?
So they can catalyse reactions.
What do chemical reactions usually involve things being?
Either split apart or joined together.
How do enzymes work?
- Every enzyme has an active site with a unique shape that fits onto the substance involved in a reaction. 2. They usually only catalyse one specific reaction. This is because the substrate has to fit into its active site. If the substrate doesn’t match the enzyme’s active site, then the reaction won’t be catalysed.
What is a substrate?
The substance an enzyme acts on.
What does changing the temperature do to an enzyme-catalysed reaction?
It changes the rate of the reaction.
How can an enzyme be denatured?
If the temperature is too hot, or the pH is too high/low, 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.
What do all enzymes have that they work best at?
An optimum temperature and pH (usually pH 7, however the enzyme pepsin works best at pH 2 because it breaks down proteins in the stomach, which means it’s well-suited to the acidic conditions there.
