1. Bioelements O biogenic elements.
Are the chemical elements that are part of living matter. We found about 70 chemical elements forming part of living matter, these are in various proportions and not all are present in all living things. In accordance with its wealth divide:
- Bioelements Primary: These are found in greater proportion, are present in all biomolecules. Represents around 95% by weight of living matter. They are the C, O, H, N and to a lesser extent P and S.
These items have been selected among all those who constitute the Earth's crust to form living matter, although except oxygen are the most abundant, possessing features among which are the following:
1-have incomplete outer electron shells. This can easily form covalent bonds and give rise to biomolecules.
2 º "They have small size, since they have a low atomic number, so that when combined, form very strong bonds difficult to break causing very stable molecules.
3 º-Because the oxygen and nitrogen are very electronegative elements, many biomolecules are polar and therefore soluble in water, which is important since most of the chemical reactions that occur in the body occur in the water.
* Molecules are polar molecules that have an asymmetric distribution of electrical charges.
4 º-Carbon has 4 electrons in its outer shell, which allow you to form 4 covalent bonds that are directed toward the corners of an imaginary tetrahedron. Has ability to bind to other carbon atoms by single bonds, double or triple in chains more or less long, branched or not, that constitute the backbone of all organic molecules, some of great complexity.
5th-The C can be connected by covalent bonds with the N, H, O and S, thus entering the skeleton of organic molecules a variety of functional groups that provide physical properties of molecules and chemical characteristics.
6 º-Sulfur and phosphorus are links that can be hydrolyzed easily, therefore, are suitable for high-energy bonding.
7 th-The majority bioelements can be easily incorporated into living organisms from the external environment, as found in molecules (CO 2, H 2 O, nitrates) that can be captured easily.
· Bioelements side: They are all the other elements that form living matter. They represent about 5% by weight of living matter. They are in smaller proportion than the previous ones but are also important, to the point that some are indispensable.
"Some are found in all living things as: Ca, Na, K, Mg, Cl, Fe, Si, Cu, Mn, B, E, F,
"Others are only present in some living things such as Pb, Br, Zn, Co, etc.
Bioelements those found in living matter in a lower rate of 0.1% is also called trace elements or trace elements. Generally play a catalytic part of enzymes, vitamins, hormones.
2.FUNCIÓN OF bioelements.
- Bioelements primary
Among the primary functions of bioelements (C, H, O, N, P and S) should be noted the following:
- Carbon, hydrogen and oxygen. They belong in different proportions of all biomolecules.
- Nitrogen. Part of important biomolecules such as proteins and nucleic acids.
- Phosphorus. It is found in nucleic acids, phospholipids, ATP, skeletal structures, etc.
- Sulfur. It is part of many proteins (those with cysteine) of some enzymes and vitamins, etc..
· Side Bioelements
¨ The most abundant secondary bioelements:
- Chlorine, sodium and potassium. In ionic form and maintain osmotic balance involved in nerve impulse transmission.
- Calcium. In the form of carbonate skeletal structures is part of many animals (bones, teeth, shells, etc.), in ionic form is involved in many processes such as muscle contraction, blood clotting, neurotransmitter release at the synapse, mitotic spindle formation etc..
- Magnesium. Part of many enzymes in the composition of chlorophyll, and so on.
¨ Among the trace elements:
- Iron. It participates in oxidation-reduction processes giving or taking electrons. Part of important proteins such as hemoglobin and myoglobin involved in oxygen transport, cytochromes involved in cellular respiration.
-Iodine: It is necessary for the production of thyroid hormone.
-Fluoride is part of the tooth enamel and bone.
- Cobalt: Part of vitamin B 12 and nitrogenase used by some bacteria to fix atmospheric nitrogen.
- Silicon: In the form of silicon oxide gives stiffness to the stems of many plants (grasses, horsetails, etc.) and is part of the carapace of microorganisms such as diatoms.
-Copper and Zinc act as cofactors of many enzymes.
- Lithium: increased secretion of neurotransmitters and enhances the stability of mood.
3. Biomolecules: CONCEPT
The bioelements in living matter is not free but unite with each other by chemical bonds forming molecules or so-called complex biomolecules or immediate principles. They are called immediate early because they can be separated from living matter by physical processes such as evaporation, filtration, distillation, electrophoresis, etc..
The biomolecules can be divided into two groups:
-Organic: They are unique to living matter, have a high percentage of carbon. Many of them are very complex and are called macromolecules or polymers being formed by the union of a simpler units called monomers.
-Inorganic: They are present both in living and in lifeless.
¨ Water is essential for life because it has chemical properties that allow you to perform very important functions. It is so important that it is free from any organism dies, only some lower organisms such as protozoa and certain organs such as seeds can significantly reduce the amount of water, but then move into a dormant life considerably reducing their activities.
4.2. STRUCTURE OF WATER
Water has a very distinctive structure that determines its properties.
• The water molecule is made up of 2 atoms of hydrogen and oxygen, each hydrogen atom is attached to the oxygen atom through a single covalent bond (sharing a pair of electrons). These atoms are arranged in space at an angle of 105 º with oxygen at the apex.
• The water molecule is dipolar, it is because, although the net charge is 0, when oxygen more electronegative than hydrogen, more strongly attracts the bonding electrons and are therefore closer to the oxygen atom that of the hydrogen atoms, this makes it appear 2 zones with different charges: one with negative charge, where the electron density (d -) is greater in the region with the oxygen atom and, another positively charged, where electron density (d +) is lower in regions occupied by hydrogen atoms.
• The polar character of the water molecule is of great importance as it allows water molecules can join together with other polar molecules and ions through weak electrostatic attractions called hydrogen bonds (*). This link is established between the oxygen atom of a molecule (negative) and the hydrogen atoms of other (positive). Each water molecule can form up to 4 hydrogen bonds, although these links are much weaker than covalent (1 / 20), break and are constantly being created allowing water to form polymers consisting of up to 8 or 9 water molecules are arranged to form a lattice-type structure. This explains many of the properties held by the water
*) The hydrogen bonds are intermolecular electrostatic attractions that occur between an electronegative atom of a molecule and a hydrogen atom from another molecule that is linked by covalent bond to another electronegative atom (O, N, etc). They are about 20 times weaker than covalent.
4.3. PHYSICAL-CHEMICAL PROPERTIES OF WATER
Because of its polar water has a very characteristic set of properties primarily:
1-A T is ambient temperature in the liquid state, contrary to what occurs with other molecules of similar molecular weight as CO 2, NO 2 etc.. This is due to the dipole, since the molecules to form polymers are held together.
2 º-links through hydrogen bonds lasting a very short time, break and are constantly being created that makes it non-sticky but smooth.
3 º-has a high cohesive force due to hydrogen bonds that exist between molecules, this makes it almost incompressible liquid having a high surface tension is that its free surface to form a laminate hard to break.
4 º-has a high bond strength is strongly can be attached to the vessel walls, through hydrogen bonds that occur between water molecules and other polar molecules. This commitment together with cohesion are responsible for the phenomena of capillarity that allow water to ascend through very thin tubes which is very important in the transport of crude sap through the wood vessels.
5 º-has a high specific heat. Much heat is required to vary the T th grade as part of the energy is spent not on increasing T ª but in breaking the hydrogen bonds.
6 º-has a high heat of vaporization.Much heat is required to go from liquid to gas, this is because to pass the gaseous state must first break all hydrogen bonds and it spent some energy.
7 º-has a great capacity of solvent is the liquid that dissolves more substances, therefore it is considered as the universal solvent. This is because their polarity can be interposed between the ions in the crystal lattices of ionic compounds and reduce the attraction between them leading to their separation and therefore its dissolution. Also due to the ability of forming hydrogen bonds with polar substances dissolve those substances with polar groups
8 th-The solid water is less dense than liquid, so ice floats on liquid water. This allows the aquatic environment, in cold weather, the existence of life beneath the ice sheets.
4.4. WATER FEATURES
Due to the properties they have, water plays many important roles among which include:
1 - Metabolic Function: It is the means which produce the majority of metabolic reactions, since the substances to react must be dissolved. Moreover, in many of these reactions, water acts as a reagent such as in the hydrolysis reactions that occur in digestion. It is also the source of hydrogen in plant photosynthesis
2 - Function Conveyor Water acts as a vehicle for transport of substances within the body and between outside and inside of it, because it is liquid and is an excellent solvent, substances are transported dissolved in it.
3 - Structural function: Because of the high strength adhesive and cohesive shapes the cells lacking rigid membrane regulating the changes and deformations of the cytoplasm.
4 - Function Buffer and lubricants: Due to the low viscosity, acts as a lubricant to facilitate sliding between the bodies and the frictional damping.
5 - thermoregulatory function: Due to the high specific heat and the high heat of vaporization, regulates body temperature of the softening the abrupt changes in the external ª T and helps maintain constant body temperature of the animals or endothermic homeotherms.
It is the physical process by which equalizes the concentration of two solutions having different concentration if they are separated by a semipermeable membrane, which only passes through it solvent molecules (water) and not of solute. Through this process moves water more dilute solution to the more concentrated until the concentration of both solutions are equal. The amount of water passing depends only on the concentration of solutions and not the nature of the solute, thus contribute equally to osmotic phenomena salts and organic substances.
The solution that has a higher concentration is called hypertonic or hyperosmotic, while the more dilute it is called or hypoosmotic hopotónica if both have the same concentration are called isotonic or isoosmotic.
Osmotic pressure (p) would be the pressure that must be done to stop the flow of water through the semipermeable membrane due to osmosis.
Cell membranes act as semipermeable membranes, so it is important that the cells are in osmotic equilibrium with the extracellular fluid that bathes them.
§ The cell is in a hypertonic medium on the intracellular environment, then loses water. Animal cells decrease their volume, shrivel and become dehydrated and may even die. In plant cells the membrane off the wall which can cause breakage of the cell. This phenomenon is called plasmolysis
§ The cell is in a hypotonic medium on the intracellular environment, then enter the water within it, resulting swell increasing the volume and internal pressure, this phenomenon is called turgor. In the case of animal cells can reach burst in the absence of cell wall, this fact is called hemolysis. In the case of plant cells and bacteria do not explode due to the cell wall.
§ The cell is in an isotonic medium compared to the cell water enters and leaves the same amount.
8. IONIZATION OF WATER: pH SCALE
Pure water behaves as a weak electrolyte and is partially dissociated into H + and OH - according to the following equation:
¾¾¾¾® H 2 O H + + OH --
In the water dissociation is very weak, meaning that most of the water is as undissociated H 2 O and only a small part is decoupled.
The product of the concentrations of H + and OH - is constant and is called the ion product in water at 25 º C is:
[H +]. [OH -] = 10 -14
In pure water for each H + is formed, it forms an OH - what causes the concentration of both ions is the same.
[H +] = [OH -] = 10 -7
If one increases the concentration of ions reduces the other to keep constant the product.
There are substances that when dissolved in water, increases the concentration of hydrogen ions are called acids. Others do decrease the concentration of hydrogen ions are called bases.
The acidity of a solution is determined by the [H +], Sorensen devised the pH scale to express the hydrogen ion concentration of a solution and therefore the acidity.
PH = - log [H +]. The value ranges from 0 to 14.
· If the pH of a solution is 7 as in pure water, the solution is neutral. H + = OH --
· If the pH is <7, the solution is acidic. H +> OH -.
· If pH is> 7, the solution is basic. H + <OH -.
The pH scale is logarithmic, meaning that if it increases or decreases in one unit means that the concentration of H + will be 10 times lower or higher.
9. SYSTEMS buffer or buffering
The liquids that form the internal environment have a constant pH near neutrality. For biological processes taking place in the internal environment to develop normally, it is necessary that there are no abrupt changes in pH.
In the metabolic processes are continuously emitting acidic and basic pH vary. To avoid this living beings have evolved chemical mechanisms whose function maintain the pH of the internal environment. These mechanisms are the buffer solutions, regulatory, buffer or buffer
These solutions consist of a mixture of two substances that act as one and the other as acid base and which are kept in balance. By and large they are a weak acid and salt of this acid.
The operation essentially consists of the following:
AH ¬ ¾ ¾ ® A - + H +
· If there is an increase of H + in the medium pH decreases, the equilibrium shifts to the left, serving the basic component of the regulator, which reacts with them and lowers the concentration of H + and pH increases.
· If there is a decrease in pH increases the H + -, the equilibrium shifts to the right, acting the acid component of the regulatory and releasing H + by increasing its concentration and decreasing pH.
The most important springs in living things are: phosphates and carbonates
Carbohydrates are organic biomolecules that consist primarily of C, H and O.
Its general empirical formula is C n H 2n O n = n (CH 2 O), some may vary slightly, which suggested they were composed of hydrated carbon atoms and therefore are known carbohydrate or carbohydrates, we now know that it does not and therefore this name is not correct but is still used.
From a chemical standpoint carbohydrates are sugar alcohols (alcoholic or have multiple hydroxyl groups-OH) and a carbonyl group (-C = O) which can be aldehyde or ketone. Therefore we can say that they are polihidroxialdehídos or polihidroxiacetonas.
The term carbohydrates that these compounds are known from the Greek "glykos" which means sweet, this can lead to confusion because not everyone has a sweet taste.
Carbohydrates are classified according to their structure. into two main groups:
· Bears or monosaccharides: They are simple carbohydrates that exist are not hydrolyzable, they can have from 3 to 9 carbons, although the most common are between 3 and 6. They are the units or monomers from which they originate other carbohydrates.
Among them as the basis of the carbonyl group is divided into two groups:
¨ aldose. The carbonyl group is an aldehyde.
¨ Ketoses. The carbonyl group is a ketone.
· Osity: They are more or less complex carbohydrates formed by the union of several monosaccharides or monosaccharide derivatives exclusively (Holósidos) either by monosaccharides or monosaccharide derivatives and other compounds glucidic (glycosides). These compounds are decomposed by hydrolysis into constituent monomers.
Within this group are different in turn two groups:
¨ Holósidos. Osity are composed entirely of monosaccharides or derivatives thereof. Depending on the number of monosaccharides is divided into two groups:
Oligosaccharides. Contain between 2 and 10 monosaccharides. The most important are the disaccharides
Polysaccharides. They consist of more than 10 monosaccharides. Among them is divided into two groups according to their composition.
Ñ homopolysaccharides. They consist of a single type of monosaccharides.
Ñ heteropolysaccharide. They consist of more than one type of monosaccharide.
¨ Glycosides. Osity are composed of monosaccharides or monosaccharide derivatives and other molecules glucidic not different in nature. According to these differ several groups: glycolipids, glycoproteins, and so on.
3.1. FEATURES AND CLASSIFICATION
They are also called bears. They are simple carbohydrates that exist can not be hydrolyzed into simpler ones.
Solid, white, water soluble, sweet and crystallizable.
Strictly conform to the chemical definition of polyols with an aldehyde or ketone group, ie are polihidroxialdehídos or polihidroxicetonas. In all but one carbon carry an alcohol group (hydroxyl OH) and the one who does not carry a carbonyl group: aldehyde or ketone.
All monosaccharides due to the presence of the carbonyl group (aldehyde or ketone) with reducing power against certain substances, such as Fehling liquor which reduces and consequently red-making, this serves to recognize their presence.
The general empirical formula is C n H 2n O n where n is the number of carbon atoms can vary between 3-9, although most often ranging from three to six.
Monosaccharides are divided into two groups depending on which carbonyl function: if called aldose aldehyde, if called ketonic ketose. Within each of these groups according to the number of carbons, in turn are different subgroups. They are named by prefixing the completion bear a prefix that indicates the carbonyl function, if aldo keto aldehyde and ketone, and then if another that indicates the carbon number. Ex aldo-tri-osa.
Major groups of monosaccharides
-Aldotetroses: erythrose, threose-aldopentoses: ribose, arabinose
-Aldohexose: glucose, mannose, galactose.
3.4. Important Monosaccharide
· Trioses: The molecular formula is C 3 H 6 O 3. Not usually found free in large quantities in nature. They are important intermediaries in cell metabolism. These include:
D-glyceraldehyde which is a aldotriose
dihydroxyacetone which is a cetotriosa
· Pentoses: Molecular Formula C 5 H 10 O 5. These include:
-D-ribose: A aldose, is presented as furans. It is part of the RNA, ATP, NAD.
-D-2-deoxyribose. It is a monosaccharide derivative is formed to replace the OH of the ribose C-2 by a hydrogen. It is important because it's DNA.
-D-ribulose: It is a ketose. It participates in the Calvin cycle of photosynthesis by fixing CO 2atmospheric.
· Hexoses: They have the molecular formula C 6 H 12 O 6. These include:
-D-glucose: It is an aldose, is presented as a piranha. You can find free in many fruits especially grapes which gives a sweet taste. Also found in the blood of animals, in humans at a concentration of 1 g / l. It is part of other more complex carbohydrates (starch, glycogen, maltose etc.) as can be obtained by hydrolysis thereof. It is the main fuel used for fuel cells, and in the case of the single neurons.
-D-galactose: It is an aldose, is presented as a piranha. It is a component of lactose, is also part of polysaccharides (pectin) and glycolipids (brain).
-D-fructose: A ketose, furanose form is submitted. He is free in many fruits. Part of the sucrose.
Carbohydrates are formed by the union of several molecules of monosaccharides or derivatives of monosaccharides that are joined by 0-glycosidic bonds or O-glycosidic.
The 0-glycosidic bond is a covalent bond formed by reacting two groups alcoholics two different monosaccharides in the composition shows a water molecule and two monosaccharides are joined by an oxygen bridge.
The O-glycosidic bond can be:
· Monocarbonílico: When the link is established between the carbonyl carbon of the first monosaccharide and a carbonyl carbon is not the second, bringing the carbonyl carbon of the second monosaccharide is free and therefore compounds that exhibit this link retain the reducing power. In other words the link is formed by reacting the OH hemiacetal of the first monosaccharide with a second OH but not with the hemiacetal and therefore is free the second monosaccharide hemiacetal OH and therefore the present compounds that retain the reducing power.
· Dicarbonyl: When the link is established between the carbonyl carbon of the two monosaccharides, which is not free either and therefore compounds that have lost the reducing power. In other words the link is formed by reacting the OH hemiacetal of the two monosaccharides, so it is not free either and therefore the present compounds do not retain the reducing power.
The O-glycosidic bond that can be independently mono or dicarbonyl may be at or ß, depending which is the first monosaccharide ao ß anomer.
Under No monosaccharide that form within the two groups differ holósidos: oligosaccharides and polysaccharides.
Carbohydrates are formed by the union of between 2 and 10 monosaccharide hexoses normally, that bind to one another through 0-glycosidic bonds.
No Monosaccharides ¾¾¾¾® oligosaccharide + (n-1) H 2 O
Are split by hydrolysis into monosaccharides that form.
They are sweet-tasting, soluble, crystallizable.
Under the No form of monosaccharides that can differentiate various groups. Each group will be appointed by prepending a prefix (di, tri, tetra, etc.). Who shows us the # of them that they formed the word saccharide.
They are the major oligosaccharides are formed by joining 2 monosaccharides, hexoses usually through an 0-glycosidic bond.
2 monosaccharides (C 6 H 12 O 6) ¾ ¾ ¾ ® disaccharide (C 12 H 22 O 11) + H 2 O
By hydrolysis breaks the O-glycosidic bond and disaccharides are split into monosaccharides that form.
Disaccharides reducing power will or will not depending on whether the link is O'glucosídico mono or dicarbolínilico.
They are named as follows:
"First, indicate the name of 1 monosaccharide finish osil
"Then in brackets indicates between which carbon is given the link
-Finally appointing finished 2nd monosaccharide into a bear, if the link is monocarbonílico and if dicarbonyl osity.
Ex maltose = a D glucopyranosyl (1-4) to D glucopyranose
The main disaccharides are:
· Maltose: Found in sprouted grains of barley. It is obtained by partial hydrolysis of starch and glycogen. This consists of two aD glucopyranose molecules that are joined by a link to monocarbonílico (1-4). The name is: aD glucopyranosyl (1-4) aD glucopyranose.
· Lactose: The sugar in milk. He is free in the milk of mammals. This consists of a molecule of ß-D galactopyranose and a aD glucopyranose that are joined by a link monocarbonílico ß (1-4). The name is: ß-D galactopyranosyl (1-4) aD glucopyranose.
· Sucrose: Is sugar cane or beets we eat regularly. This consists of a molecule of aD glucopyranose and a ß-D fructofuranose that are joined by a link to dicarbonyl (1-2). The name is: aD glucopyranosyl (1-2) ß-D fructofuranose.
· Isomalt: Not found free in nature. Obtained by hydrolysis of the branch points of amylopectin starch and glycogen. This consists of two aD glucopyranose molecules linked by a link to (1-6). The name is: aD glucopyranosyl (1-6) aD glucopyranose.
· Cellobiose: Not found free in nature, comes from the partial hydrolysis of cellulose. This consists of two molecules of ß-D glucopyranose linked by a link ß (1-4). The name is: ß-D glucopyranosyl (1-4) ß-D glucopyranose.
They are more or less complex carbohydrates that are composed of monosaccharides or monosaccharide derivatives and other substances or aglycon aglycone glucidic calls that may be of different types such as proteins, lipids and so on. The main ones are:
· Glycolipids: The aglycone is a lipid called ceramide, gangliosides and cerebrosides stand. They are part of the membranes.
· Nucleosides and nucleotides: Formed by a pentose carbohydrate and other substances (nitrogen bases). Nucleic acids.
· Glycoproteins: The non-carbohydrate molecule is a protein in nature, include:
-Glycoproteins and prothrombin blood involved in clotting, immunoglobulins with defensive function.
Gonadotropin-secreting pituitary as luteotrophic and foliculotropa ..
-Glycoproteins that are present in cell membranes, act as chemical messengers and receptors of infectious microorganisms. They are the signs of identity of the cells.
Carbohydrates have the following functions:
· Energy function: The monosaccharides and disaccharides have energy function, ie to serve the agency that obtains energy through oxidation, energy will be used to conduct business. Glucose is the main fuel used by cells such as neurons and some unique. The energy value of carbohydrate is 4 kcal / gr.
- Function Reserve: Some carbohydrates such as certain polysaccharides such as starch and glycogen, are used by organisms as energy reserve, stored glucose thus, constitute a perfect system to accumulate a large amount of glucose inside the cell, that this will increase in excess osmotic pressure. When you need energy these compounds are hydrolyzed and glucose was obtained, which subsequently oxidize to release energy.
"Structural function: Some carbohydrates are used by living organisms to produce structures, so we have:
-Cellulose, pectin and hemicellulose form the walls of plant cells.
-Chitin forms the exoskeleton of arthropods and the wall of fungi.
Wall-forming bacterial peptidoglycan.
"Chondroitin is part of bone and cartilage.
-Ribose and deoxyribose forms part of the structure of nucleic acids.