Essential Characteristics and Components of Living Beings

Posted on Dec 13, 2024 in Biology

Defined Functions of Living Beings

  • Nutrition: Exchange of matter and energy with the outside
  • Reproduction: Leaving offspring, keeping the species
  • Engaging: Layers respond to stimuli

Bioelements

All living things have a restricted group of parent chemical elements (C, H, N, P, S) that have special properties to build molecules of living beings. They constitute 98% of its weight.

Children (Ca, K, Mg, Cl, I, Cu, Zn) – some do not reach 0.1% and receive the name “trace” due to their low proportion (Fe), but are indispensable.

Biomolecules

It’s the combination of the bioelements atoms between them or with others by chemical bonds, resulting in molecules +/- complex. They can be organic (lipids, carbohydrates, nucleic acids, proteins) or inorganic (water and mineral salts).

Inorganic Biomolecules: Water and Minerals

Formed by two atoms of H and one of O, it has a high electronegativity, which produces an excess of negative charge on the O and positive charge on the H. Although the molecule is neutral, it is polar. Between the molecules are electrostatic attraction forces that hold them together by hydrogen bridges. It has very high specific heat, is the principal biological solvent, reaches maximum density, and is ionized.

  • Precipitated Salts: They have a structural function and give substance to the bones or shells.
  • Dissolved Salts: They are in ionic form and can alter the pH. They have regulatory and specific functions, helping to maintain fluid balance through osmotic phenomena (water passes through a semipermeable membrane from a region of low solute concentration to a higher concentration).

In two solutions of different concentrations, the net movement of the particles is directional, from the region of higher to lower concentration.

Carbohydrates

These are ternary compounds (C, H2, and O2).

  • Monosaccharides: Formed by a single molecule, they may have from 3 to 7 atoms of C. They can be aldose (aldehyde) or ketose (ketone).
  • Disaccharides: Groups of two monosaccharide molecules that have been detached from molecules of H2O. Sugars are simply a result of the union of two monosaccharides. They are usually solid, and their product is a molecule of H2O. They can result from the union of an anomeric C (that carries the functional group) and another anomeric or not.
  • Polysaccharides: Result from the union of many monosaccharide molecules.

Functions of carbohydrates: Fuel cell (sugar used as an energy source), storage of energy reserves, structural components.

Lipids

These are compounds formed by H, C, and O. They are composed of a nonpolar or low polarity, are insoluble in water but soluble in organic solvents. According to the presence of double bonds or simple, they can be saturated when there are double bonds or unsaturated when they do not exist.

  • Fats: Are formed by the union of a tri-alcohol, glycerol, to one to three fatty acids, ester-type covalent bonds. They can be saturated (abound in animals, solid at room temperature) or unsaturated (abound in plants, liquid at room temperature).
  • Waxes: They have instead of a tri-alcohol, a long-chain mono-alcohol that is attached by an ester bond to a fatty acid. They serve to protect.
  • Phospholipids: Consist of an alcohol molecule that has a nonpolar end (hydrophobic) and a polar one (hydrophilic). When put together, the polar and nonpolar are associated (lipid bilayers). They form the basis of the cell membrane.
  • Steroids: Several rings are derived from hydrocarbons. They are totally insoluble in water (cholesterol, vitamin D, and sex hormones).

Functions of lipids: Energy reserve for animals, structural protective coating function, structural basis for cell membranes, regulator of life processes.

Proteins

Organic biomolecules formed by C, H, O, and N. They are polymers formed by peptide bonds of a certain number of amino acid subunits (they have an amino and a carboxyl group). Amino acids are amphoteric substances because they can behave as an acid.

Functions of proteins:

  • Structural: As collagen fibers form resistance.
  • Transport: As hemoglobin transports oxygen in blood or cholesterol.
  • Regulatory: Such as the hormone insulin that regulates blood sugar.
  • Contractility: As actin and myosin form filaments whose interaction is derived from muscle contraction.
  • Immune Defense: Antibodies are produced to neutralize foreign substances that enter the body.
  • Catalytic or Bioenzymatic: Enzymes are biological catalysts that increase the speed of metabolic reactions.

Hydrolases

These are a group of enzymes that catalyze the breakage of covalent bonds by incorporating a molecule of water (hydrolysis).

Properties of enzymes:

  • Specificity: An enzyme can only act on a particular substrate and catalyzes only one type of reaction.
  • Efficient: A single molecule can catalyze the transformation of many molecules of substrate per minute.

Nucleic Acids

Biomolecules are formed by C, H, N, and P. They are polymers whose subdivisions are called nucleotides. Polynucleotides are formed by covalent bonds between groups of the phosphodiester phosphate type.

Nitrogenous Bases

Nitrogenous bases are cyclic organic compounds, which include two or more N atoms.

  • Pyrimidine Bases: Are derived from the pyrimidine ring and have a unique structure. They are cytosine, thymine, and uracil.
  • Purine Bases: Derived from purine and are formed by two rings. They are adenine and guanine.

Types of Nucleic Acids

  • DNA: Nitrogenous bases are adenine, cytosine, guanine, and thymine. It is located in the nucleus and part of the chromosomes. It is also found in small amounts in the mitochondria and chloroplasts. It has a double helix structure with two antiparallel strands. The nitrogenous bases are directed towards the interior of the double helix while the pentose and the phosphate groups form an external skeleton. The structure is stable because hydrogen bonds are formed between the complementary nitrogenous bases (A=T and C≡G).

Functions of DNA:

  • Carrier of hereditary information. This information is coded and makes the base sequence. If the sequence changes, so does the hereditary information.
  • Has double layers and allows your information to be inherited.
  • The cell uses information from DNA to elaborate proteins responsible for its own functioning.
  • RNA (C, U, A, G):
  • Messenger RNA: Is responsible for copying DNA information and taking it to the ribosomes, where it assists in protein synthesis.
  • Ribosomal RNA: Part of ribosomes.
  • Soluble or Transfer RNA: Formed by tiny molecules that transport amino acids to ribosomes so that the protein chain is built.