Biomolecules and Water: Essential Life Components

Inorganic and Organic Biomolecules

Inorganic biomolecules can also be found in mineral matter, such as water and mineral salts. Organic biomolecules are exclusive to living things and include carbohydrates, nucleic acids, proteins, and lipids.

The Properties and Composition of Water

Each water molecule contains two atoms of hydrogen (H) and one atom of oxygen (O) joined together by covalent bonds. Water presents polarity, and there are two distinguished zones with different charge signs. Because of this, water molecules are considered dipoles.

One molecule of water and those that surround it establish attraction forces to unite opposite charges. These bonds are called hydrogen bridges.

The Biological Influence of Water

Water constitutes the majority of the cytoplasm and acts as a temperature moderator.

Understanding Carbohydrates

Carbohydrates are organic biomolecules formed by carbon, oxygen, and hydrogen. Chemically, they are polyhydroxyaldehydes or polyhydroxyketones. They are divided into three main groups:

1. Monosaccharides

These are the simplest carbohydrates. They consist of a chain containing between 3 and 7 atoms of carbon (trioses, tetroses, pentoses, hexoses, etc.).

• Aldose: A monosaccharide with an aldehyde group.
• Ketose: A monosaccharide with a ketone group.

Characteristics include being sweet, white, and soluble in water. Their primary function is for energy. When chemical reactions occur, the rupture of links happens alongside the formation of new ones. If the new links have more energy than those that broke, the reaction releases energy (exergonic); if the opposite occurs, it is an endergonic reaction.

2. Disaccharides

This union is formed by two monosaccharides. The bond occurs between a carbon and an OH group, and the aldehyde or ketone group of another, creating a glycosidic link. The reverse reaction (to obtain free monosaccharides) is called hydrolysis.

Characteristics: Sweet, crystallizable, and soluble. Function: Energetic contribution to cells.

3. Polysaccharides

These consist of many monosaccharides joined by glycosidic links. Characteristics: Not sweet, do not crystallize, and are generally insoluble.

Energy Reserve Functions

• Starch: The reserve substance in plants.
• Glycogen: The animal equivalent of starch. The difference lies in the frequency of the chain branching.

Structural Functions

• Cellulose: Forms the cell walls of plant cells.
• Chitin: The main component of the exoskeleton of insects.