Chemical reactions in organism’s bodies ( Metabolism & Enzymes )
Living organisms life depends on the occurrence of chemical reactions inside their bodies , these reactions are called metabolism , Metabolism is necessary for growth , repairing the damaged tissues and obtaining the energy .
Metabolism is a group of biochemical reactions take place inside the living cells , in which : Some molecules are broken down to extract the chemical energy stored in their chemical bond , This process is called catabolism .
Complex and macromolecules are being built from simple molecules , This process is called anabolism , Metabolism is divided into the catabolism and the anabolism .
The catabolism is the process of breaking down of macromolecules into simple ones to extract the energy stored in the chemical bonds of these molecules , such as releasing the energy from the glucose oxidation process during cellular respiration .
Anabolism is the process of using simple molecules for building more complex substances throughout a chain of chemical reactions that consume the energy , such as synthesis of proteins from amino acids and Photosynthesis in green plants .
In order to biochemical reactions ( metabolism ) to occur , They need high activation energy to get started , Therefore , There should be a catalyst ( enzyme ) to reduce the activation energy , to reduce the cell consumption of more energy and to ensure the occurrence of the chemical reaction more rapidly .
Activation energy is the minimum energy needed in order for a chemical reaction to occur .
Enzymes are biological catalysts made up of protein molecules and increase the speed of chemical reactions inside the cell .
The origin of word Enzyme : Enzyme is a Latin word means ( in the yeast ) where the enzymes had been discovered at the first in the process of glucose fermentation into alcohol by the yeast .
Properties of Enzymes
Enzymes participates in the chemical reactions inside the cell to speed up them without being affected or consumed ( they are similar to the other chemical catalysts ) .
Enzymes are highly specific than other chemical catalysts where each enzyme is specific to : one reactant substance called substrate and One type or few types of reactions .
Enzymes lower the activation energy needed to get the reaction stared .
Enzymes are affected by hydrogen ion concentration ( pH ) and temperature in their action .
Factors affecting the speed of enzyme action
Temperature , Hydrogen ion concentration ( pH ) , Enzyme concentration , Substrate concentration and Presence of inhibitors .
Enzymes are sensitive to thermal changes because they are made up of protein substances .
Enzymes activity is determined in a narrow range of temperatures ( comparatively to the ordinary chemical reactions ) , Where : Each enzyme has an optimal temperature at which the enzyme is more active and it ranges between 37 : 40 degree Celsius .
Enzyme optimal temperature is the temperature at which the enzyme is more active ( 37 : 40 degree Celsius ) , The enzyme minimal temperature is the temperature at which the enzyme is less active .
The enzyme activity gradually decreases , as the temperature rises more than the optimal temperature until it reaches a certain temperature at which the enzyme activity stops due to the change of its normal composition and the enzyme will not return back to its activity by decreasing temperature .
When the temperature decreases below the optimal temperature , the enzyme activity decreases until the enzyme reaches a minimum temperature at which the enzyme activity is the least and it stops completely at 0 degree Celsius , but the enzyme restores its activity ( reactivated once more by rising the temperature .
Temperatures are recorded on some detergents to use them properly in order to the activity of enzymes they contain do not affected .