4 December 2023

Carbohydrates, also known as carbohydrates or carbohydrates, represent one of the main groups of biomolecules present in living beings. They are composed of carbon, hydrogen, and oxygen in different proportions and are classified into monosaccharides, disaccharides, and polysaccharides. Let’s know more about them!

Definition and concept of carbohydrates in chemistry

In chemistry, carbohydrates are organic biomolecules made up of carbon, hydrogen, and oxygen. They are classified as ‘sugars’ and are characterized as polyhydroxyaldehydes or polyhydroxyketones. Carbohydrates act as source of energy in living things and are essential for the proper functioning of the body. These are divided into three categories main:

  • monosaccharideswhich are the simplest carbohydrates and can combine to form disaccharides and polysaccharides.
  • disaccharideswhich are sugars formed by the union of two monosaccharides.
  • polysaccharideswhich are long chains of monosaccharides.

Carbohydrates have several functions in the human body, such as energy production, formation of cell structures and regulation of metabolism. Likewise, carbohydrates are also used in the food industry and in the production of biofuels.

What are the characteristics of carbohydrates?

Carbohydrates, also known as carbohydrates or carbohydrates, are organic biomolecules made up of carbon, hydrogen and oxygen. Some of its main features are:

  • Chemical composition: Carbohydrates are composed of carbon, hydrogen and oxygen, with a general empirical formula of (CH2O)nwhere ‘no‘ represents the number of carbon atoms in the molecule.
  • Solubility: Monosaccharides and disaccharides are soluble in water due to the presence of hydroxyl groups (-OH) in their structure, which allows them to interact with water molecules. Polysaccharides are insoluble in water due to their large size and complexity.
  • Function energetic: Carbohydrates are an important source of energy for the organism, since they are break down into glucose and are used as fuel for cells. Glucose is converted to ATP (adenosine triphosphate), the main source of energy for chemical reactions in the body.
  • Structure molecular: Carbohydrates have a molecular structure that can be linear or branched, depending on the type of carbohydrate. Monosaccharides can have a cyclic structure, while disaccharides and polysaccharides are linear or branched.
  • Polarity: Carbohydrates are polar molecules due to the presence of hydroxyl groups (-OH), which allows them to interact with other polar molecules, such as water. This is important for their function as structural components and as a source of energy in the body.
  • Function structural: Polysaccharides can have an important structural function in living beings, such as in the case of cellulose, which forms the cell wall of plants. Some carbohydrates can also be part of the structure of proteins and lipids.
  • storage function: Polysaccharides can also be used as a source of Energy storage in living beings, as in the case of starch and glycogen. It should be noted that starch is found in plants and glycogen in animals.

What is the function of carbohydrates?

Carbohydrates have multiple functions in the body, the main one being to provide energy to the body. When the carbohydrates are digested and broken down into glucosethis glucose is used by the body’s cells as fuel to carry out their functions, such as muscle contraction, protein synthesis and the transmission of nerve impulses, among others.

In addition to their energy function, carbohydrates may also have other important functions in the body, depending on the type of carbohydrate. Some functions of carbohydrates include:

  • Function structural: Some carbohydrates, such as cellulose, are part of the cell structure and tissues, providing resistance and support.
  • Function of storage: Carbohydrates can be stored in the form of starch in plants, and glycogen in animals, to be used as power source in times of need.
  • Function of protection: Some carbohydrates may have a role in protecting the body, such as glycolipids and glycoproteinswhich are part of the cell membrane and have immunological recognition and protection functions.

How are carbohydrates classified?

The carbohydrates can be classified into different groups based on their chemical structure and size. The main classifications of carbohydrates are described below:

  • monosaccharides: They are the simplest carbohydrates. They cannot be hydrolyzed into smaller carbohydrates and therefore can never be broken down by hydrolysis. They have the general formula (CH2O)n, where ‘n’ can be equal to 3, 4, 5, 6, 7, or 8. Some examples of monosaccharides are glucose, fructose and galactose.
  • disaccharides: They are molecules formed by the union of two monosaccharides thanks to a glycosidic bond, and can be hydrolyzed to obtain two monosaccharides. Some examples of disaccharides are sucrose, made up of glucose and fructose; lactose, made up of glucose and galactose; and the maltymade up of two glucose molecules.
  • OligosaccharidesThey are molecules formed by the union of 3 to 10 monosaccharides through glycosidic bonds. They are found in cell membranes and may have cell signaling and recognition functions.
  • polysaccharidesThey are molecules formed by the union of more than 10 monosaccharides. They have structural and storage functions in living beings. Some examples of polysaccharides are cellulose, starch, and glycogen.
  • Carbohydrate derivatives: They are molecules that are derived from carbohydrates and have specific functions, such as amino sugars, glucuronic acids and neuraminic acids.
  • reducing carbohydrates: Are those carbohydrates that have the ability to reduce chemicals, like Benedict’s reagent, due to the presence of an aldehyde or ketone group in its structure. Some examples of reducing carbohydrates are glucose, maltose and lactose.
  • carbohydrates No reducers: They are those carbohydrates that they do not have the capacity to reduce chemical substances due to the absence of an aldehyde or ketone group in its structure. Some examples of non-reducing carbohydrates are sucrose, oligosaccharides and polysaccharides that do not contain aldehyde or ketone groups.
  • carbohydrates simple: They are those carbohydrates that are not hydrolyzed into smaller molecules, such as monosaccharides and disaccharides.
  • carbohydrates complex: They are those carbohydrates that are hydrolyzed into smaller molecules, such as oligosaccharides and polysaccharides.

What is a cyanogenic carbohydrate?

A cyanogenic carbohydrate is a type of carbohydrate that can release hydrocyanic acid or cyanide when hydrolyzed. These compounds are toxic and can cause poisoning if consumed in great quantities.

Cyanogenic carbohydrates are found in certain plants, especially those belonging to the families Rosaceae, Legumes, and Apiaceae. Some examples of plants that contain cyanogenic carbohydrates are apple seedsapricot kernels, cherry seeds, cassava, flax and bitter almonds.

In some cultures, cassava is used as a food source but must be properly processed to remove toxic compounds. It is important to exercise caution when consuming these plants and follow proper processing recommendations to minimize the risk of cyanide poisoning.

What is a non-assimilable carbohydrate?

A non-assimilable carbohydrate is a type of carbohydrate that cannot be digested or absorbed by the human digestive system. In other words, these carbohydrates are not used as a source of energy by the body.

Unassimilable carbohydrates are commonly found in foods such as fruits, vegetables, grains, and legumes, and a common example is dietary fiber, a form of carbohydrate that cannot be digested. Dietary fiber is divided into two categories:

  • The Soluble fiberwhich dissolves in water and forms a gel in the intestine.
  • The insoluble fiberwhich does not dissolve in water and helps to increase the volume of stool.

Although non-assimilable carbohydrates do not provide the body with energy, they do have health benefits. Dietary fiber, for example, helps prevent constipation, reduces the risk of heart disease, improves glycemic control, and promotes a healthy intestinal tract. For all this, it is important include non-assimilable carbohydrate sources in the diet to maintain good digestive and general health.

What is the structure of carbohydrates?

Carbohydrates are organic molecules composed of carbon (C), hydrogen (H) and oxygen (O). Its structure may vary, but in general are made up of basic units called monosaccharideswhich are simple sugars.

The monosaccharides, in turn, are made up of a carbon skeleton that has an aldehyde or ketone group on one end and several hydroxyl (-OH) groups on the other carbons.

The most common monosaccharides are glucose, fructose, and galactose, each with a slightly different structure. More complex molecules can be formed from monosaccharides, such as disaccharides, which are composed of two monosaccharides joined by a glycosidic bond. Some examples of disaccharides are sucrose, lactose, and maltose. In addition, larger and more complex molecules such as polysaccharides can also be formed from monosaccharides.

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