What are carbohydrates?

This article is about carbohydrates, the most important energy source of humans and other living things, their benefits, types and all their features. If you are interested in the question "what are carbohydrates", this article is for you. Let's start.

Carbohydrates can often be described as simple organic compounds made up of carbon (C), hydrogen (H) and oxygen (O) atoms. However, some varieties may contain nitrogen (N) as well as these three elements. Carbohydrates, the most important energy source of all living things, consist of sugars and polymers.

What Are the Benefits of Carbohydrates?

Living things need nutrients to meet their energy needs and perform their basic functions. Of these, carbohydrates are the food groups that the body uses first. The functions and properties of carbohydrates, both fuel and structural materials of cells, are as follows:

• They are the main energy sources of plants and animals.

• While plants produce their own glucose molecules through photosynthesis, animals and humans take the carbohydrates they need from the outside.

• They are found in the structure of the cell membrane along with oils and proteins.

• They give the cell membrane antigenic properties, that is, they protect the cell membrane against external dangers.

• They keep the water in the body. For this reason, they can cause weight gain when consumed too much by people.

• They participate in the structure of nucleic acids, such as DNA and RNA. They are also used for the formation of ATP, which is considered the main source of energy.

• Plants or animals can be found in the cells of all living things. For example, they join the cell wall in bacteria and fungi and exoskeleton in insects. In plants, they are found in the structure of the cell wall.

What are Carbohydrate Types?

It is important to know which carbohydrates are healthier for a healthy diet. Therefore, it is useful to know the types of carbohydrates and which of them are healthier.

Carbohydrates are grouped by the number of simple sugar molecules they contain. These; They are listed as monosaccharides, disaccharides and polysaccharides.

1.Monosaccharides (Simple Sugars)

It is the first type of carbohydrate that we often use in daily life, but which has a lot of negative effects on health. They cannot be divided into smaller units by hydrolysis and are also called single or simple sugars for this.

Monosaccharides are found in fruits and milk. They are naturally sweet. They dissolve when placed in water. For example, sugar water solution.

The formulas (CH20) are shown as n. The ratio of hydrogen and oxygen in their structures is similar to that of water. The number of carbon atoms they carry can be between 3-7.

Monosaccharides are named according to the number of carbon atoms they carry. For example, fructose contains glucose and sub galactose carbon. Ribose and deoxyribose are simple sugars containing five carbons. The sweetest sugar is fructose, called fruit sugar and it is herbal. Galactose, of animal origin, is sugar in milk.

Glucose is grape sugar and it is the most used carbohydrate type in respiration by living cells. It is the most important fuel of cells. It can come together to form disaccharides and polysaccharides from other types of carbohydrates. It can also participate in the structure of the cell membrane in the form of glycoproteins and glycolipids.

In the context of healthy eating rules, they should not be consumed daily above a certain value. Because the excess glucose taken into the body is converted into fat and stored. When they are consumed for a long time, they can disrupt the blood sugar balance.

Normally, every healthy person has 75 to 110 mg of glucose in 100 ml of blood sample. If the amount of glucose is more than this value, the risk of diabetes and obesity may be increased.

2.Disaccharides

Disaccharides are formed by the combination of simple sugars. If two molecules of monosaccharide are combined, the sugars formed are called disaccharides. This phenomenon is called dehydration synthesis, since water is produced during the assembly of monosaccharides. These reactions are anabolic since larger molecules are formed from smaller molecules. Disaccharides, like monosaccharides, are water-soluble.

While two simple sugars bind with the glycoside bond, as a result of dehydration, a water molecule is exposed and a disaccharide molecule is formed. (It should be noted that the glycoside bonds are covalent bonds.)

• Simple organic molecules combine with various chemical bonds to become larger molecules and water is released. These reactions are called “dehydration synthesis”. The formation of disaccharides from monosaccharides is an example of this event. Also, the combination of amino acids and the formation of proteins is dehydration synthesis.

Formations of disaccharides can be expressed by the following equations.

Glucose + Glucose → Maltose + H2O

Glucose + Fructose → Sucrose + H20

Glucose + Galactose → Lactose + H2O

As seen from the equations above, two glucose combine to form a maltose molecule and 1 molecule of water. Maltose is called barley sugar. They are synthesized in plant cells.

If a glucose molecule and a fructose molecule combine, a molecule sucrose, that is, tea sugar and a molecule of water. Sucrose, like maltose, is formed in plant cells. It is the most abundant disaccharide type in the world.

If a glucose molecule and a galactose molecule combine, a molecule lactose and a molecule water are formed. Lactose is milk sugar. They are synthesized in animal cells. These formations are examples of dehydration.

Equations can also occur from the reverse side. These events, which are the opposite of dehydration synthesis, are called hydrolysis. The process of decomposition of large molecules formed as a result of dehydration into smaller molecules or building blocks with water is called "hydrolysis".

Maltose + H2O → Glucose + Glucose

Sucrose + H20 → Glucose + Fructose

Lactose + H2O → Glucose + Galactose

In the first of the hydrolysis events seen in equations, maltose decomposes into glucose with the help of water. Sucrose is divided into glucose and fructose with the help of water. Lactose decomposes into glucose and galactose.

3.Polysaccharides

Polysaccharides are larger molecule compounds formed by the combination of monosaccharides. In other words, they are formed by connecting a large number of monosaccharides with a glycoside bond. The fusion of a polysaccharide molecule can be represented by the following equation.

(n) Monosaccharide → Polysaccharide + (n - 1) water

Looking at the polysaccharide formation equation from monosaccharides, it is seen that when n monosaccharide molecules come together, (n-1) water molecules are formed.

This process is a dehydration synthesis as it forms large molecules from small molecules. We have already mentioned that water is released in dehydration synthesis.

The number of water molecules formed is as much as the number of glycoside bonds between monosaccharides. For example, 1 bond is formed between 2 simple sugars. There are 2 bonds between 3 simple sugars.

If there are as many (n) monomers in the medium (n-1) as glycoside bonds, which means that (n-1) water molecules are formed.

Cells synthesize polysaccharides for two main purposes.

The first task; to ensure the storage of sugar and energy. For storage, starch and glycogen are used.

The second task of the polysaccharides is to provide mechanical support. For example, they support cells as cellulose and chitin structure molecules.

They are synthesized as starch and cellulose in plant cells, glycogen and chitin in animal cells. Polysaccharides are found in fungal cells as glycogen and chitin. If you wonder what is starch, glycogen, cellulose and chitin, what are its functions, you can read the section below.

What is Starch? What does it do?

The storage polysaccharides of plants are starch molecules. Thousands of glucose molecules are connected by α - glycoside bonds and form starch. The following equation will be quite guiding for their formation.

(n) Glucose → Starch + (n - 1) water

According to this equation, n glucose combines to form the starch molecule. In addition, as many as the number of bonds, water molecules were exposed. The number of bonds is as mentioned before (n - 1).

Unlike simple sugars, starch molecules do not dissolve in water. When iodine reagent and starch come together, blue color is formed.

Although starch molecules do not dissolve in water, enzymes found in living things such as plants, animals and fungi break down starch molecules. The breakdown of starch results in glucose that forms it. The glucose formed is usually used in breathing.

It is of vegetable origin. For example, potatoes are a complete starch store. Therefore, those who want to gain weight can consume more potatoes. As understood from the example, starch molecules are stored in plants such as roots, stems, leaves, seeds and fruits. However, it is not stored glucose, but starch molecules.

Plants store starch, not glucose, balance the osmotic concentration of the cell. Because glucose can be dissolved in the cell. However, starch does not dissolve in the cell. Thus, plant cells do not swell with excessive water.

What is Glycogen?

Polysaccharides are stored as glycogen in animals, fungi and bacteria. The places where it is stored in humans are the liver and muscles. However, the liver depot is limited. So it needs to be constantly renewed. If food is not eaten for a long time, it will be exhausted within a few hours.

Glycogen is multi-branched. However, unlike starch molecules, they dissolve in water. Its formation is the same as starch. In other words, by connecting thousands of glucose molecules with the α - glycoside bond, glycogen molecules are formed. Their formation can be shown by the following equation.

(n) Glucose → Glycogen + (n - 1) water

According to the equation, when (n) glucose molecules come together, (n - 1) α - glycoside bond is established. In other words, the water molecule is released as much as the α - glycoside bond.

When iodine reagent and glycogen come together, a brown and red color is formed.

What is Cellulose? (What Is The World's Plenty Carbohydrate?)

A large part of the plant mass consists of cellulose. In other words, polysaccharides are found in the structure of plants. Cellulose is insoluble in water and is known as the most abundant carbohydrate on earth.

Cellulose molecules that participate in the structure of the cell wall in plants are formed as a result of binding of thousands of glucose molecules with the β - glycoside bond. They have a linear structure. Their formation can be shown in the equation below.

(n) Glucose → Cellulose + (n - 1) water

As can be seen from the equation, (n) glucose molecules combine to form cellulose molecules and (n - 1) water molecules are released.

If cellulose is added to iodinated zinc chloride solution, its color is painted blue.

Cellulose molecules are insoluble in water, such as starch. So how do herbivores eating excess cellulose digest cellulose?

Herbivorous animals feed on plants and prokaryotic creatures are found in their intestines. The most important task of prokaryotic organisms is to digest cellulose in plants. People who are both carnivorous and herbivorous cannot digest cellulose.

Fiber foods should be consumed for a healthy diet. Water-insoluble cellulose is one of the fiber foods. Cellulose molecules increase the secretion of mucus and allow nutrients to move easily through the intestines. In other words, cellulose prevents wastes from staying in the body for a long time.

Fruits, vegetables and cereals are rich in cellulose. For this, attention should be paid to the consumption of vegetables and fruits 2 -3 meals a day.

What does Chitin mean?

Its structure is similar to cellulose and it is polysaccharide. Its composition contains a side group that carries carbon, hydrogen, oxygen and nitrogen. Their pure state is quite soft.

They are the most used carbohydrates in medicine and industry. For example, they are used for making self-melting surgical thread. However, if calcium carbonate salt is added to the structure of chitins, they will become quite hard.

Chitins join the structure of the cell wall in mushrooms. Insects, spiders and other arthropods are found in the structure of the exoskeleton. However, it is not found in the cell membrane of insects. This is one of the most confused issues.