Enzymes
Catalyst
A catalyst is a substance which can alter or speed up a chemical reaction, without itself being chemically changed at the end of the reaction.
Enzymes
Proteins that function as a Biochemical catalysts.
Can either break down or build up proteins.
Build up
Break down
building proteins from amino acids into protein
breakdown of glucose during respiration
building glycogen from glucose
breakdown of polysaccharides into monosaccharides. eg : starch into maltose into glucose.
Characteristics Of Enzymes
Enzymes are required in minute amounts
Enzymes are specific in action
Enzymes speed up chemical reactions
Lock and Key hypothesis
Enzyme speed up a chemical reaction by lowering the activation energy needed to start the reaction.
A small amount of enzyme can catalyse a large number of chemical reactions
Each chemical reaction inside a cell is catalysed by a unique enzyme, An enzyme is specific due to its three dimensional shape. The Lock And Key hypothesis explains how the shape of an enzyme affects the way it functions.
According to the Lock And Key hypothesis, enzyme reaction depends the specific size of the active site [ chemical reactions are taken place in the Active Site ] The Active Site is complementary to the enzyme. Just like a lock and a key. The enzyme is the lock and the substrate is the key.
Substrate
The substance where enzyme acts on is called a Substrate
Enzymes are affected by Temperature
Enzymes at suitable temperature are called the Optimum Temperature.
Enzymes are affected by pH level
Enzymes are inactive and has lesser reaction when temperature is too low.
At optimum temperature, the rate of enzyme activity will increase. Thus, the chances of the substrate and the enzyme clashing and fitting will increase. Hence, a chemical reaction will occur.
If the temperature is too high for the enzyme, the enzyme will get denatured. The higher the temperature. The higher the rate of denaturation to occur.
Enzymes are affected by the alkalinity or acidity of the solution. When it is too alkali, the rate of activity is lesser. Thus, the reaction will take place slower or longer.
Denaturation is the change in the three dimensional structure of an enzyme or any other soluble protein.
Enzymes has a specific 3D shape. When denatured, the structure will change drastically. Thus, the substrate will not fit into the enzyme as it is now denatured.
At a suitable ph. It is called as the optimum pH level.
When the solution is too acidic, the enzyme will denature.
The lower the pH level, the higher the acidic the solution is. The higher the pH level, the high the alkali level and the lower the acidic level.
The neutral pH level is 7
The average temperature for most enzymes is between 36-40 degrees.