Biochemistry of Life | Explaining The Molecular Basis of the Human Body

Title: Biochemistry of Life | Explaining The Molecular Basis of the Human Body

Author: Yinka Okunlola

Subject: Science

Language: English

Introduction

It has been established that just like natural occurrences, Humans are subjected to scientific and natural laws around us. The same theories applying to inanimate or inorganic matters have an equivalent effect on organic (life) matters. However understanding basic chemical principles will go a long way in understanding how human body is put together and how it works as a whole. According to some evolutionary understanding, it is stated that life could have been formed from natural gases which come together to form complex bio-organic molecules that includes the building blocks of life. The chemistry of the cell depends on the reactions of smaller molecules and ions, either organic or inorganic. However let’s study the biochemistry of man.

Chemical basis

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Atoms form the Basis of every living organism

The world contains a variety of physical substances called Matter. Matter is anything that has mass and occupies space. All forms of matter are made of small particles known as Atoms. Atoms are the smallest and basic unit of matter that cannot be broken into simpler form by an ordinary chemical means. These atoms consist of three fundamental particles: Protons (positively charged), neutron (uncharged) and electrons (negatively charged). The proton and the neutron form the nucleus which is surrounded by a spherical cloud of electrons. The chemical identity of an atom is determined by the number of Proton which is known as the Atomic Number. An Element is a pure form of matter containing only one kind of atom. Elements are fundamental substances that make up everything in and on earth. Some atoms of the same element can be found to have the same number of proton but a different no of neutron; however these atoms are called Isotopes Isotopes that are unstable and exhibit radiation emitting properties are called Radioisotopes. Radioisotopes have been of good use in the field of medicine and at the same time dangerous to life. Two or more elements combine to form a substance called Compound. The atoms in these compounds are held to one another by a chemical bond forming a stable association called Molecules.

Chemical Bonding

Compounds which contain the element carbon and hydrogen are classified as organic, and all others are Inorganic. Biochemical processes in the body are based upon how atoms hold to one another; how they bind and break apart. When atoms join together they form a chemical bond; covalent or ionic. Covalent bonds are formed when an atom share its electron with another atom. This bond form a strong and stable link between them e.g H2O. Ionic bond is formed by a complete transfer of electron from an atom to another for both of them to attain a stable octet. Ionic bonds are weaker than the covalent bonds.

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Micromolecules are linked by Chemical Bonds to form macromolecules or polymers

Electrolytes

Ionic compounds in solution are called Electrolytes. They conduct electricity and are essential for muscle and nerve function. Some exert osmotic pressure keeping body fluids proportionate in their right compartments. Some electrolytes function as buffer in acid-base balance to maintain a stable pH range of body fluids. The body regulates electrolytes like Na2+, Hco3-, Cl-, H+, OH- to attain a favorable pH for metabolism.

pH and Buffer Actions

Since the body function in relation to electrolyte activities, then it has a high tendency of building high Acidosis or extreme Alkalinity. In order to maintain a stable internal environment, it creates a Buffer action to regulate this phenomenon. All Body metabolism or mechanism requires specific range of pH either Acidic or Alkaline. For instance, the body demands an acidic pH in the stomach for the activation of gastric enzymes and to kill bacteria. In contrast to this the Duodenum which is an extension of the stomach needs an alkaline pH for the secretion and activation of intestinal enzymes. This phenomenon of variation in pH occurs in many part of the body as needed and is regulated by electrolyte control. The buffer system maintains homeostasis by preventing drastic changes in pH value in the blood. The blood in action with the excretory system work to achieve the acid-base balance so that the pH remains within normal range.

Body Fluids

The body is made up of about 60-75% of fluid, and this fluid is found to be in different proportion in different compartments. The body fluid is regulated across two different compartments; the ECF and ICF. The flow of the body fluid just like any fluid also obeys Diffusion and Osmosis. Diffusion and Osmosis occur in the body to regulate movement of solute and solvent. This phenomenon is responsible for Concentration of Urine, Hardening of stool, and Dryness of the mouth.

Organic Molecules

Organic compounds contain carbon and hydrogen atoms, and some in addition contains oxygen, sulphur, nitrogen and phosphorus. Each carbon atom forms a four valence covalent bond. Carbon atoms has a potential to bind strongly to other carbon and giving it the characteristics of forming long chains, branch chains, rings or any three dimensional shape. In this case, many carbon atoms (monomers) can join together to build very large molecules (polymer). There are four types of organic molecules found in living cells- carbohydrates, proteins, lipids and nucleic acids.

Carbohydrates are molecules with basic constituents of carbon, hydrogen and oxygen. It is commonly known as sugar and starch. It has a major functionality of providing energy. It is categorized into three types based on the complexity of the molecules; they are monosaccharide, Disaccharides and Polysaccharides. Carbohydrate is metabolized to monosaccharide (majorly glucose) which is then absorbed in the intestine or stored as glycogen.
Lipids are organic chemicals that have a major property of being insoluble in water. They are important source of energy having more energy content than carbohydrates or proteins.
Proteins constitute about 18% of the body mass forming all the major structural and functional aspects. Proteins contain Carbon, Hydrogen, Oxygen and Nitrogen as the major components while Sulphur and Phosphorus are minor constituents. Proteins are made by polymerization of amino acids through peptide bonds (CO-NH). Abnormality in protein structure will lead to molecular diseases with profound alterations in metabolic functions.
Nucleic Acids are molecules concerned with the storage and transfer of genetic information. They are polymers of nucleotides whic are monomers made of three components; a ribose sugar, a phosphate group and a nitrogenous base. Nucleic acids are the most important of all biomolecules as they function to create and encode and then store information in the nucleus of every living cell. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

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These Bio-molecules undergo contemporary metabolic reactions to maintain the functionality of the entire organism

Chemical control system

The body consists of two major control systems; the nervous system and the endocrine system. The nervous system is known to control the body through integration of signals and responses around the body while the endocrine system controls the body through secretion of hormones to the target cells to induce an action. These control system doesn’t just function at random but comprehends a chemical-molecular protocol.

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Neurotransmitters convey signals between two neurons

For instance, the nervous system transmits signals by neurotransmitters. The nervous system is characterized by synapse which are junctions between two neurons; one (pre-neuron) transmitting to the other (post-neuron). These neurons are not in end-to-end contact but they exhibit the use of certain chemicals (neurotransmitters) like Noradrenaline, Acetycholine and Gama Amino-Butyric Acid (GABA) to carry and transmit excitatory or inhibitory impulse. On the other hand, hormones are secreted by endocrine glands and carried in the blood to a target tissue, at arrival it binds to a specific area (receptor) where it act to influence chemical and metabolic reactions inside the cells. In addition, Enzymes also alter biochemical reactions by increasing the rate at which they occur. Enzymes are organic catalysts that speed up the rate of chemical reactions in the body. In every cells a number of chemical reactions occurs contemporarily at dispense of temperature and pH factors. These reactions if considered naturally at room or body temperature, they occur very slowly, but in the presence of Enzymes, the rate of reaction is increased without altering temperature or pH in the cytoplasm.

Conclusion

Although an organism might be complex and complicated, but it functions as a result of chemical and molecular interactions; obeying different natural laws and striving to adjust to fit to its environment. Understanding the chemistry of processes in man has really provided a practical knowledge of understanding man as a natural organism. Every occurrence or metabolismin the body takes it root from the molecular basis; Homeostasis, Digestion, Drug actions, Diseases, Disorders, allergies, adaptation, evolution, mutation etc and they all satisfy chemical protocol.

Reference

- Heineman Advanced Science Biology- Ann Fullick - https://www.livescience.com/3505-chemistry-life-human-body.html - https://en.wikipedia.org/wiki/Biochemistry