Bioelements - Lecture notes 1 PDF

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in this class we saw everything about the bioelements...

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BIOELEMENTS: ESSENTIAL ELEMENTS FOR LIFE Chemicals that are part of living things. Attending to its abundance (non-importance) can be grouped into three categories: Primary or main bioelements: C, H, O, N They are the majority elements of living matter, constituting 95% of the total mass. The physical-chemical properties that make them suitable are the following 1. They form among them covalent bonds, sharing electrons 2. Carbon, nitrogen and oxygen, can share more than one pair of electrons, forming double and triple bonds, which gives them a great versatility for the chemical bond 3. They are the lightest elements with the ability to form covalent bond, so these links are very stable. 4. Because of the tetrahedral configuration of the carbon bonds, the different types of organic molecules have different three-dimensional structures. This spatial conformation is responsible for biological activity. 5. Carbon combinations with other elements, such as oxygen, hydrogen, nitrogen, etc., allow the emergence of a wide variety of functional groups that give rise to the different families of organic substances. These present different physical and chemical characteristics, and give to the organic molecules specific properties, which increases the possibilities of CRandation of new organic molecules by reaction between the different groups. 6. The bonds between the carbon atoms can be simple (C-C), double (C = C) or triple, allowing more or less long, linear, branched chains and rings to form. Secondary bioelements S, P, Mg, Ca, Na, K, Cl we find them as part of all living beings, and in a proportion of 4.5%. Sulfur: It is found in two amino acids (cysteine and methionine), present in all proteins. Also in some substances such as coenzyme A Phosphorus: It is part of the nucleotides, compounds that form nucleic acids. They are part of coenzymes and other molecules such as phospholipids, fundamental substances of cell membranes. It is also part of phosphates, abundant mineral salts in living things. Magnesium: It is part of the chlorophyll molecule, and in ionic form it acts as a catalyst, along with enzymes, in many chemical reactions of the organism. Calcium: It is part of calcium carbonates of skeletal structures. In ionic form it intervenes in the muscular contraction, blood coagulation and transmission of the nerve impulse. Sodium: abundant cation in the extracellular medium; necessary for nerve conduction and muscle contraction. Potassium: A more abundant cation inside the cells; necessary for nerve conduction and muscle contraction. Chlorine: more frequent anion; necessary to maintain the balance of water in the blood and interstitial fluid.

Trace elements They are thus called to the set of chemical elements that are present in the organisms in vestigial form, but that they are indispensable for the harmonic development of the organism. Some 60 trace elements have been isolated in living beings, but only 14 of them can be considered common for almost all, and these are: iron, manganese, copper, zinc, fluorine, iodine, boron, silicon, vanadium, chromium, cobalt, sElenio, molybdenum and tin . The functions they play are reflected in the following table: Iron Fundamental for the synthesis of chlorophyll, catalyst in chemical reactions and forming part of cytochromes that are involved in cellular respiration, and in the hemoglobin that intervenes in Oxygen transport. Manganese It intervenes in the photolysis of the water, during the process of photosynthesis in the plants. Iodine Necessary for the synthesis of thyroxine, hormone that intervenes in metabolism Fluoride It is part of the tooth enamel and the bones. Cobalt It is part of the vitamin B12, necessary for the synthesis of hemoglobin. Silicon It provides resistance to connective tissue, hardening plant tissues as in the Grass. Chrome It is involved with insulin in the regulation of blood glucose. Zinc It acts as a catalyst in many reactions of the organism. Lithium It acts on neurotransmitters and cellular permeability. In adequate doses can prevent Depression States. Molybdenum It is part of the plant enzymes that act in the reduction of nitrates by The plants.

The water Water, a simple and strange molecule, can be considered as the liquid of life. It is the most abundant substance in the biosphere, where we find it in its three states and is also the majority component of living beings, since between 65 and 95% of the weight of most living forms is water. The water was also the support where life arose. Molecule with a strange behavior that makes it a different substance to most liquids, has a manifest rationabilityand possesses extraordinary physical and chemical properties that will be responsible for its importance Biological. During the evolution of life, organisms have adapted to the aqueous environment and have developed systems that allow them to take advantage of the unusual properties of water. Water structure The water molecule consists of two atoms of H attached to an atom of O by means of two covalent bonds. The tetrahedral disposition of the oxygen SP3 orbitales determines an angle between the H-O-H bonds approximately 104 '5 º, in addition the oxygen is more electronegative than the hydrogen and draws more strongly to the electrons of each link. The result is that the water molecule, although it has a neutral total load (equal number of protons that of electrons), presents an asymmetric distribution of its electrons, which converts it into a polar molecule, around the oxygen concentrates a density of Negative charge, while the hydrogen nuclei are stripped bare, partially deprived of their electrons and thus manifest a positive charge density. So in practice the water molecule behaves like a dipole. Thus, dipoledipole interactions are established between the water molecules themselves, forming hydrogen bonds or bridges, the negative partial oxygen load of a molecule exerts electrostatic attraction over the positive partial loads of the atoms of Hydrogen from other adjacent molecules. Although they are weak unions, the fact that around each molecule of water are disposed four other molecule joined by bridges of hydrogen allows to form in the water (liquid or solid) a structure of type reticular, responsible in large part of its Abnormal behavior and the peculiarity of its chemical physical properties. Water properties 1. Solvent action Water is the liquid that more substances dissolves, so we say it is the universal solvent. This property, perhaps the most important for life, is due to its ability to form hydrogen bridges with other substances that may present polar or ionic-laden groups (alcohols, sugars with R-OH groups, amino acids and proteins with groups that They present loads + and-, which gives rise to molecular dissolutions. Also water molecules can dissolve saline substances that dissociate forming ionic dissolutions. In the case of Ionic dissolutions (Fig. 6), salts ions are attracted by the water dipoles, being "trapped" and coated with water molecules in the form of hydrated ions or solvated. The solvent capacity is responsible for two functions: 1. Medium where metabolism reactions occur 2. Transportation Systems 2. High cohesion Force Hydrogen bridges keep the water molecules tightly bonded, forming a compact structure that makes it an almost incomprehensible liquid. By not being able to compress it can work in some

animals like a hydrostatic skeleton, as it happens in some perforating worms able to pierce the rock by means of the pressure generated by its internal liquids. 3. High adhesion strength This force is also related to the hydrogen bridges that are established between the water molecules and other polar molecules and is responsible, along with the cohesion of the socalled capillarity phenomenon. When a capillary is inserted in a container with water, it ascends through the capillary as if it climbs clutching the walls, until reaching a level higher than that of the vessel, where the pressure exerted by the water column, is balanced with the capillary pressure. This phenomenon is partly due to the ascent of the crude sap from the roots to the leaves, through the woody vessels. 4. High specific heat This property is also related to the hydrogen bridges that are formed between the water molecules. Water can absorb large amounts of "heat" that it uses to break the p.de H. So the temperature rises very slowly. This allows the aqueous cytoplasm to protect against temperature changes. This keeps the temperature constant. 5. High Heat vaporization It serves the same reasoning, also the p.de H. are responsible for this property. To evaporate the water, first you have to break the bridges and then provide the water molecules with enough kinetic energy to move from the liquid phase to the soda. To evaporate one gram of water, 540 calories are required, at a temperature of 20 º C. Water functions Water functions are intimately related to the properties described above. They could be summarized in the following points: 1. Support or medium where metabolic reactions occur 2. Thermal Shock Absorber 3. Transport of substances 4. Lubricant, rubbing cushion between organs 5. Promotes circulation and Turgor 6. Gives flexibility and elasticity to tissues In general, it must be said that life is developed at pH values close to neutrality. Living organisms do not support variations of pH greater than a few tenths of unity and therefore have developed over the course of the evolution buffer or buffer systems, which maintain the pH constant through homeostatic mechanisms. Buffer systems consist of a conjugated acidbase pair that act as protons giver and acceptor respectively. Bicarbonate buffer is common in intercellular fluids, maintaining the pH in values close to 7.4, thanks to the balance between the bicarbonate ion and carbonic acid, which in turn dissociates into carbon dioxide and water; If the concentration of hydrogenies in the medium is increased by any chemical process, the balance is shifted to the right and the excess of CO2 produced is eliminated to the outside. If on the contrary decreases the concentration of hydrogenies of the medium, the equilibrium moves to the left, for which it is taken CO2 of the external medium.

Osmosis 1. Osmosis and osmotic pressure If we have two aqueous dissolutions of different concentration separated by a semipermeable membrane (let the solvent pass but not the solute), the phenomenon of osmosis is produced which would be a type of passive diffusion characterized by the passage of water (solvent) to Through the semipermeable membrane from the most diluted (hypotonic) to the most concentrated (hypertonic) solution, this racking will continue until the two solutions have the same concentration (isotonic or isoosmotic). And it is understood by osmotic pressure the pressure that would be necessary to stop the flow of water through the semipermeable membrane. The plasma membrane of the cell can be considered as semipermeable, and therefore the cells must remain in osmotic equilibrium with the liquids that bathe them. When the concentrations of extracellular and intracellular fluids are the same, both dissolutions are isotonic. If the extracellular fluids increase their concentration of solutes become hypertonic with respect to the cell, and this one loses water, they dehydrated and die and if on the other hand the extracellular means are diluted, they become hypotonics with respect to the cell, the water tends to Enter and the cells swell, they become perky, even coming to burst. 2. Diffusion and Dialysis The fluids present in the organisms are dispersions of various substances in the water. Depending on the size of the particles, molecular dispersions or True dissolutions are formed, as is the case with the mineral salts or organic substances of small molecules, such as sugars or amino acids. The dispersed particles can also provoke the movement of osmosis, these other two: Dialysis. In this case, they can cross the membrane in addition to the solvent, low molecular weight molecules and they pass through the membrane from the most concentrated solution to the most diluted. It is the foundation of hemodialysis that attempts to replace deteriorated renal filtration. Diffusion would be the phenomenon by which dissolved molecules tend to distribute themselves evenly within the water. It can also occur through a membrane if it is sufficiently permeable. This is how the gas exchanges and some nutrients are made between the cell and the environment in which it lives. Mineral salts In addition to water there are other inorganic biomolecules such as mineral salts. Depending on its solubility in water, two types are differentiated: insoluble and water-soluble. 1. Water-insoluble salts. They form solid structures, which usually have a supporting or protective function, such as: Internal vertebrate skeleton, in which we find phosphates, chlorides, and calcium carbonates. Shells of calcium carbonate from crustaceans and molluscs. Hardening of plant cells, as in grasses (impregnation with silica). Otoliths of the inner ear, formed by crystals of calcium carbonate equilibrium. 2. Water-soluble salts.

They are dissociated in their ions (cations and anions) that are responsible for their biological activity. They perform the following functions: Catalytic functions. Some ions, such as Cu +, Mn2 +, Mg2 +, Zn +,... They act as enzymatic cofactors. Osmotic functions. They intervene in the processes related to the distribution of water between the cellular interior and the medium where the cell lives. The ions of Na, K, Cl and Ca, participate in the generation of electrochemical gradients, essential in the maintenance of membrane potential and the potential of action and neuronal synapse. Capping function. It is carried out by the carbonate-bicarbonate systems, and also by the monophosphate-bisphosphate. CARBOHYDRATE CONCEPT Carbohydrates are biomolecules basically formed by carbon (C), hydrogen (H) and oxygen (O). Carbon atoms are attached to alcoholic groups (-OH), also called radicals Hydroxyl and hydrogen radicals (-H). In all carbohydrates there is always a carbonyl group, ie a carbon attached to an oxygen Using a double link (C = O). The carbonyl group can be an aldehyde group (-CHO), or a Cetónico Group (-CO-). Thus, carbohydrates can be defined as Polihidroxicetonas. Monosaccharides Monosaccharides are simple carbohydrates, consisting only of a chain. They are named adding The end-OSA to the number of carbons. For example, in the drawing are represented a TRIOA, a pentose and a hexose. 1. The Triosas, are abundant inside the cell, because they are intermediate metabolites of glucose degradation 2. The pentoses, are carbohydrates of 5 carbons and among them are: Ribose and deoxyribose , which are part of the nucleic acids and the ribulose that plays an important role In photosynthesis, because it is fixed CO2 atmospheric and thus It incorporates carbon into the cycle of living matter. 3. The hexoses are carbohydrates with 6 carbon atoms. They have an interest in biology, the Glucose and galactose between the Aldohexosas and the fructose between the Cetohexosas. In aqueous solution, the monosaccharides are closed forming a 5 or 6-sided ring, Furans and Pirans, respectively. Here is represented the linear and cyclic formula of fructose, forming a ring of five sides that Corresponds to the Furano when the molecule is closed the group-OH (marked in red), can occupy two positions,

With respect to the group-CH2OH of the C5. They are two new isomers, called Anómeros alfa (in trans position) and Beta (CIS position) These formulas represent glucose in its linear and cyclic form, in this case the formed ring has 6 sides And it corresponds to the Pirano skeleton. It is the most abundant carbohydrate, called grape sugar; In the blood is found In concentrations of one gram per litre when cured, it gives rise to polysaccharides with energetic function (starch and glycogen) or with structural fusion, such as plant cellulose. Monosaccharides Cycling In this scheme can be seen as the molecule closes a monosaccharide, in this case a hexose. The group Carbonyl of C1 is close to C5 and between them react their radicals in an intramolecular reaction between a group Aldehyde (C1) and an alcohol group (the C5), forming a hemiacetal. Both carbons will be joined by a Of this group, two Anómeros (alpha and beta) originate. The study of the cycle was performed by Haworth and is known as Haworth's screening name Disaccharides Disaccharides are formed by the Union of two monosaccharides, which is done in two ways: 1. By link between the C1 anomeric of a monosaccharide and a C no Anomeric of another monosaccharide, as seen in the formulas of lactose and maltose. These Disaccharides retain the reducing character. Lactose Maltose 2. By link if set between the two carbons anomeric of the two Monosaccharides, so the disaccharide loses its reducing power, for example as it happens In the sucrose Sucrose Home Page Polysaccharides The polysaccharides are formed by the Union of many monosaccharides (may vary between 11 and several thousand), by Bond O-glycosidic, similar to that seen in disaccharides, with loss of a

molecule of water for each link. They have very high molecular weights, they do not have reducing power and they can perform energy reserve functions or structural function. STARCH-FORMING POLYMERS AMYLOSE Amylopectin 2. Glycogen is the polysaccharide of the animals. It is abundantly found in the Liver and muscles. Molecule very similar to amylopectin; But with greater abundance of ramifications. Among the structural polysaccharides, stresses cellulose, which forms the cell wall of cells Vegetable. This wall constitutes a case in which the cell is enclosed, which persists after the death of this one. Cellulose is constituted by units of B-glucose, and the peculiarity of the B-link (beta) makes the cellulose unassailable by human digestive enzymes, therefore, this polysaccharide does not have Food interest for man.. Lipids Lipid concept Lipids are organic biomolecules basically formed by carbon and hydrogen and usually also oxygen; But in much lower percentages. They can also Contain also phosphorus, nitrogen and sulfur. It is a group of very heterogeneous substances that only have in common these two Features: 1. They are insoluble in water 2. They are soluble in organic solvents, such as ether, chloroform, benzene, etc. Home Page Lipid classification Lipids are classified into two groups, taking into account their own Composition fatty acids (saponificable lipids) or do not possess (insaponificable lipids). Fatty acids Fatty acids are molecules formed by a long hydrocarbon chain of linear type, and with an even number of carbon atoms. They have at one end of the chain a carboxyl group (-COOH). Some 70 fatty acids are known to be classified into two groups:

Saturated fatty acids have only simple bonds between the carbon atoms. Examples of this type of acid are myristic (14C); The Palmitic (16C) and the Stearic (18C). Unsaturated fatty acids have one or several double bonds in their chain and their molecules present elbows, with changes of direction in the places where a double bond appears. Examples are oleic (18C, a double bond) and Linoleic (18C and two double bonds). Properties of fatty acids solubility. The fatty acids have a hydrophilic zone, the carboxyl group (COOH) and a Lipófila zone, the hydrocarbon chain that presents methylene groups (-CH2-) and methyl groups (-CH3) terminals. Esterification. A fatty acid binds to an alcohol through a covalent bond, forming an ester and releasing a water molecule. Saponification. It is a typical fatty acid reaction, in which they react with alkalies and give rise to a fatty acid salt, which is called soap. The SOAP molecules simultaneously present a lipófila or hydrophobic zone, which shuns the contact with water, and a hydrophilic or polar zone, which is oriented towards it, which is called amphipathic behavior. Simple lipids They are saponificable lipids in whose chemical composition only carbon, hydrogen and oxygen intervene. Acilglicéridos They are simple lipids formed by the esterification of one, two or three fatty acid molecules with a molecule of glyceri...