Enzymes Flashcards
What are enzymes?
An enzyme is a biological catalyst
What do enzymes do?
Enzymes speed up the rate of a chemical reaction but without themselves being used in it.
Why are enzymes identified as specific?
Enzymes are identified as specific because they only catalyse one type of chemical reaction so if there are 10,000 different chemical reactions occurring then you will need 10,000 different enzymes.
What is an active site?
Enzymes are folded into complex 3D shapes that allow smaller molecules to fit into them. The place where these molecules fit is called the active site close active siteThe part of the enzyme to which a specific substrate can attach or fit on to..
What is a substrate?
A substance on which enzymes act,forming products.
What are the two models in which the way enzymes work are represented?
1) Lock and key model
2) Induced fit model
What is the LOCK-KEY MODEL?
- see diagram on book
The lock and key model is a theory of enzyme action that explains how enzymes fit their substrate. The active site of an enzyme is structured to fit a specifically shaped substrate. Once the substrate binds to the active site, the enzyme will facilitate the reaction and release products of the reaction.
What are factors that could affect the rate of an enzyme catalysed reaction?
1) Temperature
2) pH
3) Substrate concentration
How does temperature affect the rate of an enzyme catalysed reaction?
At a higher temperature both the enzyme and substrate molecules gain more KE so they move faster and they are more likely to meet up and form product. This increases the rate of reaction. At a very high temperature the active site of the enzyme will start to change a and the substrate will no longer fit into the active site so the enzyme is DENATURED or deactivated.
How does pH affect the rate of an enzyme catalysed reaction?
Enzymes are very susceptible to pH ( H+ ions to OH- ions) because the H+ ions/OH- ions will change the active site on the enzyme. They change the 3D structure of the polypeptide chains in active sites. This explains why some enzymes only work in acidic environments and others in alkaline.
How does Substrate concentration affect the rate of an enzyme catalysed reaction?
The higher the substrate concentration is the faster the rate of reaction because there is a greater chance of substrate meeting up and binding to the enzymes active site. Once the active site on the enzymes are full up then further increase in substrate concentration has no effect.
What is specificity?
The idea that enzymes only work with one substrate.
Name on type of reaction catalysed by enzymes that takes place outside cells.
Digestion of food.
Which two products are formed when lipids are broken down?
1) Fatty acids
2) Glycerol
Name the three parts of the human digestive system that produce amylase.
1) Salivary glands
2) Pancreas
3) Small intestine
