The human body is called a biochemical factory for a reason. After all, every minute thousands, tens and hundreds of thousands of processes of oxidation, splitting, reduction and other reactions take place in it. What allows them to flow at such a tremendous speed, providing every cell with energy, nutrition and oxygen?
The concept of catalysts
Both in inorganic and organic chemistry, special substances are widely used that can accelerate chemical reactions by several thousand, and sometimes millions of times. The name of these compounds is "catalysts". In inorganic chemistry, these are metal oxides, platinum, silver, nickel and others.
Their main action is the formation of temporary complexes with the reaction participants, by lowering the activation energy, the process is carried out several times faster. After that, the complex decomposes, and the catalyst can be removed from the sphere in the same quantitative and qualitative composition as before the start of the process.
There are two types of catalytic reactions:
- homogeneous - accelerator and participants in oneaggregate state;
- heterogeneous - accelerator and participants in different states, there is a phase boundary.
In addition, there are compounds that are opposite in action - inhibitors. They are aimed at slowing down the necessary reactions. So, for example, they allow you to reduce the amount of time for the formation of corrosion.
Biological catalysts are inherently different from inorganic ones, and their properties are somewhat specific. Therefore, catalysis is different in living systems.
Enzymes - what is it?
It has been proven that if the action of special substances accelerating the indicated processes were not carried out inside living systems, then an ordinary apple in the stomach would be digested for about two days. For such an amount of time, the processes of decomposition and intoxication with decay products would begin. However, this does not happen, and the fruit is completely processed in an hour and a half. This is carried out by biological catalysts, which are present in large quantities in the composition of each organism. But what are they and what is the basis of such an action?
Biological catalysts of protein nature are enzymes. Their basis is a complex structural organization with a number of specific properties. Simply put, these are unique proteins that can reduce the activation energy of processes in living organisms and carry them out at a speed that exceeds the usual values by several million times.
There are many examples of such molecules:
- catalase;
- amylase;
- oxireductase;
- glucose oxidase;
- lipase;
- invertase;
- lysozyme;
- protease and others.
Thus, we can conclude: enzymes are biological catalysts of protein nature, which act as strong accelerators, allowing thousands of processes to be carried out in living organisms at a very high speed. Digestion, oxidation, restoration are based on their action.
Similarities of inorganic and protein catalysts
Enzymes as biological catalysts have a number of properties similar to inorganic ones. These include the following:
- Speed up only thermodynamically possible reactions.
- Do not affect the shift of chemical equilibrium in equilibrium systems, but equally accelerate both the forward and reverse processes.
- As a result, only products remain in the reaction sphere, the catalyst is not among them.
However, in addition to similarities, there are also distinctive features of enzymes.
Differences according to nature
Biological catalysts have several specific features:
- High degree of selectivity. That is, one protein is able to activate only a certain reaction or a group of similar ones. Most often, the "enzyme - substrate of one process" scheme works.
- Extremely high degree of activity, because some types of proteins can speed up reactions millions of times.
- Enzymes are highly dependent onfrom environmental conditions. They are active only in a certain temperature range. The pH of the medium also strongly influences. There is a curve showing the minimum, maximum and optimum values for each enzyme.
- There are special compounds called effectors that can inhibit the nature of biological catalysts or, conversely, have a positive effect on them.
- The substrate on which the enzyme works must be strictly specific. There is a theory called the key and the lock. It describes the mechanism of action of the enzyme on the substrate. The catalyst, like a key, is embedded in the substrate with its active site, and the reaction begins.
- After the process, the enzyme is partially or completely destroyed.
Thus, it is obvious that the importance of protein catalysts is extremely high for living organisms. However, their action is subject to certain rules and is limited by environmental conditions.
Studying catalysis in school
As part of the school curriculum, catalysts are studied in both chemistry and biology. In chemistry lessons, they are studied from the point of view of substances that allow industrial syntheses to be carried out, to obtain a large number of various products. In biology lessons, it is biological catalysts that are considered. Grade 9 involves the study of molecular biology and the basics of biochemistry. Therefore, it is at this stage of education that students receive the basic knowledge about enzymes as active substances inorganisms of living beings.
Experiments are conducted at the lessons, confirming the chemical activity of these substances in certain temperature ranges and pH of the environment:
- study of the effect of hydrogen peroxide as a catalyst on raw and boiled carrots;
- effect on meat (cooked and raw), potatoes and other products.
Enzymes in the human body
Every schoolchild who is sufficiently educated and who has crossed the line of secondary education knows what biological catalysts are called. Enzymes in the body have a strictly specific specialization. Therefore, for each process, you can name your catalytic substance.
So, all the enzymes of the body can be divided into several groups:
- oxidoreductases such as catalase or alcohol dehydrogenase;
- transferases - kenase;
- hydrolases important for digestion: pepsin, amylase, lipoprotein lipase, esterase and others;
- ligases, e.g. DNA polymerase;
- isomerase;
- lyases.
Since all these compounds are of a protein nature, as well as a complex of vitamins in the composition, an increase in body temperature is fraught with denaturation of the structure, and consequently, the cessation of all biochemical reactions. In this case, the organism is close to death. Therefore, high body temperature is necessarily brought down during illness.
Use of protein catalysts in industry
Often enzymes are used in different industriesindustry:
- chemical;
- textile;
- food.
On the shelves of stores you can see cleaning products and washing powders containing enzymes - these are enzymes that improve the quality of washing clothes.
What are biological catalysts for?
It is difficult to overestimate their importance. After all, they not only allow living organisms to live, breathe, eat, carry out metabolic processes, but also give us the opportunity to destroy industrial waste, obtain medicines, protect and protect our he alth and the environment.
