Chemical classes of hormones

As hormones are defined functionally, not structurally, they may have diverse chemical structures. Hormones occur in multicellular organisms (plants, animals, fungi, brown algae and red algae). These compounds occur also in unicellular organisms, and may act as signaling molecules, but there is no consensus if, in this case, they can be called hormones.

37. Nucleic acids are polymolecules, or large biomolecules, essential for all known forms of life. Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides. Each nucleotide has three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base. If the sugar is deoxyribose, the polymer is DNA. If the sugar is ribose, the polymer is RNA.Together with proteins, nucleic acids are the most important biological macromolecules; each are found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information—in other words, information is conveyed through the nucleic acid sequence, or the order of nucleotides within a DNA or RNA molecule. Strings of nucleotides strung together in a specific sequence are the mechanism for storing and transmitting hereditary or genetic information via protein synthesis.Nucleic acids were discovered by Friedrich Miescher in 1869. Experimental studies of nucleic acids constitute a major part of modern biological and medical research, and form a foundation for genome and forensic science, as well as the biotechnology and pharmaceutical industries. Deoxyribonucleic acid (DNA) is a nucleic acid containing the genetic instructions used in the development and functioning of all known living organisms (with the exception of RNA viruses). The DNA segments carrying this genetic information are called genes. Likewise, other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information. Along with RNA and proteins, DNA is one of the three major macromolecules that are essential for all known forms of life. DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. Ribonucleic acid (RNA) functions in converting genetic information from genes into the amino acid sequences of proteins. The three universal types of RNA include transfer RNA (tRNA), messenger RNA (mRNA), and ribosomal RNA (rRNA). Messenger RNA acts to carry genetic sequence information between DNA and ribosomes, directing protein synthesis. Ribosomal RNA is a major component of the ribosome, and catalyzes peptide bond formation. Transfer RNA serves as the carrier molecule for amino acids to be used in protein synthesis, and is responsible for decoding the mRNA. In addition, many other classes of RNA are now known.

38 Theme: fundamentals of analytical chemistry.The role of analytical chemistry.

Analytical chemistry is one of the chemical disciplines. Analytical chemistry is united with other chemical sciences with common chemical laws and based on studying of chemical properties of substances. Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample, and quantitative analysis determines the amount of certain components in the substance. The separation of components is often performed prior to analysis. Analytical chemistry is the chemical science about: – theoretical base of chemical analysis of substances;

– method of detection and identification of chemical elements;

– methods of qualitative determination of substances;

– methods of selection (separation) of chemical elements and its compounds;

– methods of establishing the structure of chemical compounds.

Subjects of analytical chemistry are: chemical elements and its compounds and processing of transformation of substances in run chemical reactions.

The main tool of chemical analysis is chemical reaction as a source of information about chemical composition of substances using for qualitative and quantitative analysis.

Aims of analytical chemistry are:

1. Establishing the chemical composition of analyzed object (isotopic, elementary, ionic, molecular, phase) – qualitative analysis.

Qualitative analysis consist from

– identification – establishing of identity of researched chemical compounds with well-known substance due to compare its physical and chemical properties

– and detection – checking the presence in analyzed objects some components, impurities, functional groups etc.

2. Determination of content (amount and concentration) some components in analyzed objects – quantitative analysis.

3. Determination (establishing) of structure of chemical compound – nature and number of structural elements, its bonds one to another, disposition in space.

4. Detection of heterogeneity on surface or in volume of solids, distribution of elements in layers.

5. Research process in time: establishing character, mechanism and rate of molecular regrouping.

6. Developing of present analytical methods theory, working out the new methods of analysis.