Water

• A polar molecule with the necessary properties for life on Earth Dissolves various substances, facilitating numerous chemical reactions.

• Allows the transport of substances between cells or through the body.

• Water has high specific heat.

• Helps animals maintain body temperature, participates in perspiration.

Glycides

• Are the carbohydrates

• Monosaccharides: Glucose, Fructose, and Galactose

• Disaccharides: maltose, sucrose, and lactose.

• Polysaccharides: Starch, Glycogen, Cellulose, and Chitin.

• Energetic compounds (fuels cellular respiration).

• Structural compounds.

Lipids

• Insoluble in water, they form an adipose layer that acts as an energy reserve and helps in thermal insulation. They also participate in the formation of the plasma membrane, besides constituting some hormones and vitamins.

• Glycerides: alcohol and fats acids.

• Waxes: present in animals and vegetables.

• Steroids: hormones, bile salts, and vitamin D.

Proteins

• Main functions: Structural, enzymatic, contractile, hormonal, defense (antibodies), transport, and protection.

• Formed by the union of amino acids.

• Plants synthesize all amino acids from carbon and nitrogen sources.

• In animals, the so-called essential amino acids are not produced, so they must come from external sources and are present in the diet.

• The process of breaking the bonds that form the structures of proteins is called denaturation.

• Heat and pH variation can cause denaturation, resulting in loss of protein function.

Enzymes

• They are catalysts, providing the activation energy for chemical reactions to occur.

• Their form has an active site that allows them to bind to specific reactants.

• The enzymatic reactions are altered by some factors and are accelerated according to the increase in enzyme or substrate concentration, temperature, and acidity (each enzyme has an optimum working pH).

Nucleic acids

• In eukaryotic cells, DNA is found in the nucleus, forming the chromosomes, and also in the Mitochondria and chloroplasts.

• RNA is found in the nucleus, ribosomes, cytosol, mitochondria, and chloroplasts.

• DNA and RNA are formed by the chaining of nucleotides.

DNA (double helix model)

1. This molecule is formed by two chains of nucleotides linked by the nitrogenous bases, forming the double helix model.

2. The strands of the double helix are complementary to each other.

3. Thymine (1) binds to adenine (A), and cytosine (C) binds to guanine (G) Replication of DNA At first, enzymes unwind the double helix and break the bonds between the bases.

4. On each exposed strand, new nucleotides fit together, obeying the A-T and C-G pairing.

5. Each strand serves as the base for another.

6. That is complementary to it, so the two resulting molecules are the same as the original. This replication is called semiconservative.

RNA

• This molecule is taken up by a single strand of nucleotides.

• The bases present in this molecule are adenine (A), guanine (G), cytosine (C), and uracil (U).

Types of RNA

• RNA messenger: carries the formation that determines the sequence of amino acids of the proteins that are formed.

• RNA transporter: carries the amino acids to the site of protein synthesis.

• Ribosomal RNA: participates in the structure of ribosomes.

Protein synthesis

• The synthesis of proteins depends on DNA in interaction with RNA. Different cells will produce distinct sets of proteins.