The chemical composition of human body
To understand the use and function of the nutrients (chemicals) in the metabolic reactions that go on in the body, it will be necessary to show the chemical composition of the human body.
Like I mention in the past the human body is a composition of chemicals reacting with each other all the time.
After laying out the chemicals that make up the human body, we shall also show by the chemical reactions involved in the production of energy, how these chemicals interact with one another.
Six elements, carbon, hydrogen, oxygen, nitrogen, phosphorus and calcium make up about 99 per cent of the weight of the body. Another five elements make up 0.85 per cent of the body.
These elements are potassium, sodium, sulfur, chlorine and magnesium. 0.15 per cent of the weight of the body is made up of trace elements.
These are dietary minerals that are required in very minute quantities in their functions in the body. They function as co-factors in chemical reactions and assist in the physiological function of organs, muscles etc.
Trace elements are also required in the physiological functions of the brain and nerves in the central nervous system.
The composition of the human body can also be expressed by the molecules in it.
For example, the following molecules can be said to be found in the body: water, carbohydrates such as glucose and the glycogen stores, protein, fats and oils etc.
This being the case, these different molecules can be broken down into their elemental components. For example, water is made up of two atoms of hydrogen and a single atom of oxygen.
A carbohydrate is a macromolecule of carbon (C), hydrogen (H) and oxygen (O). The hydrogen: oxygen ratio is 2:1 as in water and the basic chemical formula of carbohydrate is Cm(H2O)n.
The letters m and n may not necessarily be the same but they represent one of the four different groups of carbohydrates. These groups are referred to as saccharides, a synonym of carbohydrate.
The four groups are monosaccharide, disaccharides, oligosaccharides and polysaccharides. Glucose, the most basic form of carbohydrates is a monosaccharide with the chemical formula C6H12O6.
Smaller carbohydrates, monosaccharides and disaccharides are usually referred to as sugars and they commonly end with the prefix “-ose.”
For example, we have glucose (grape sugar monosaccharide), sucrose (cane sugar disaccharide) and lactose (milk sugar disaccharide).
Amino acids are the organic compounds that combine together to form proteins.
They are divided into three groups, which include,
1. Essential amino acids
These are referred to as essential because they cannot be produced in the human body; they have to be supplied from external sources.
The essential amino acids are: histidine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan and valine.
2. Non essential amino acids
These are produced in the body, even though they may not come through external sources. They include: alanine, asparagine, aspartic acid and glutamic acid.
3. Conditional amino acids
Conditional amino acids may not be essential except in times of ill-health when such amino acids may be needed in higher quantities.
In this group are such amino acids as arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline and serine.
Chemical composition of amino acids
Amino acids have a basic amino group (-NH2) and a carboxyl acid group (-COOH).
Attached to this basic group is an organic R group that confers uniqueness to the amino acid.
Carbon, hydrogen, oxygen and nitrogen are the four key elements found in amino acids and after water, amino acids are the most abundant components of proteins found in muscles and cells. They are combined together into peptide chains (polypeptides) which are the building blocks of proteins.
Chemical composition of fats
Fats in the body, otherwise known as triglycerides are compounds formed by three long chain fatty acids and an alcohol, glycerol.
Glycerol is a triol which has three active hydroxyl (-OH) groups which will react with three long chain fatty acids to form triglycerides.
Fats are generally hydrophobic; they are insoluble in water but soluble in certain other solvents.
The shorter chain fatty acids are liquid at room temperature while the longer chain ones are solid.
Because of these different qualities, it is common to refer to those that are liquid at room temperature as oils and the solid ones at room temperature as fat. However, they are all lipids.