Bioinorganic Chemistry

The branch of chemistry which deals with the study of inorganic substance in the biological and biochemical systems in terms of transport, structural support, defence, therapeutic action, enzymatic action, toxicity, nutrition, environment, medicine and pharmacy, etc. is bioinorganic chemistry

Macro and micro nutrients

Carbohydrates, proteins, fats, fibres, vitamins and minerals are the major nutrients required for the normal growth and development of our living systems.
The nutrients which are present in large amount for our body are called macronutrients. eg. carbohydrate, protein, fat, fibre and water.
The nutrients which are present in a small amount for our body are called micronutrient. Vitamins and minerals are examples of micronutrient.

Importance of metal ions in biological systems

Functions of Na

• It helps in maintaining the blood volume and blood pressure.
• It is needed for the transport of sugars and amino acid into the cells.
• It maintains the osmotic pressure of our body.
• It regulates the flow of water across all membranes.

Functions of K

• It helps in muscle contraction, heartbeat and nerve impulse.
• It helps in regulating fluid balance in the body.
• It is important for the synthesis of ribosomes.
• It helps in the waste removal process.

Functions of Mg

• It is present in chlorophyll and helps in photosynthesis.
• It helps in adjusting the proper sugar level.
• It helps in the production of energy.
• It helps in the synthesis and functioning of DNA.

Functions of Ca

• It is essential for building strong teeth and bones.
• It helps in the regulation of heartbeat and blood clotting.
• It is an important constituent of the cell wall.
• It plays an important role in muscle contraction.

Functions of Cr

• It is necessary for the breakdown of carbohydrate and fat.
• It helps to stimulate fatty acid synthesis.
• It is involved in the production of red blood cells.
• It helps in cholesterol synthesis.

Functions of Fe

• It helps in oxygen carrier in the blood of mammals, birds and fishes.
• Haemoglobin, an iron-containing protein, helps to carry oxygen from lungs to tissue.
• Myoglobin, another iron-containing protein, is used for the storage of oxygen.
• It helps in the production of enzymes and hormones.

Functions of Co

• It is an integral part of cobalamin ( vitamin B12) which functions the brain and nervous system.
• It helps in the formation of red blood cells.
• It helps to stimulate the production of thyroxine, a thyroid hormone.
• It helps in fatty acid and amino acid metabolism.

Functions of Ni

• It helps in electron transfer.
• It is mostly found in nucleic acid.
• It helps to improve bones strength.
• It helps in metabolizing urea and in nitrogen fixation.

Functions of Cu

• It is used as metalloenzymes which catalyse the various biochemical reaction.
• It helps in electron transfer and oxygen storage.
• It helps in the formation of melanin pigment in the skin and for healthy hair.
• It helps in the synthesis of phospholipids.

Functions of Zn

• It is needed for the proper growth of infants.
• It helps in the regulation of gene.
• It helps in cell division and cell growth.
• It helps in wound healing.

Ion pump

It is a special protein that moves across the membrane. The protein that transport ions across a biological membrane from a region of low concentration to higher concentration are called an ion pump. They are active transport. The proteins that transport ions require energy. These transporters can be primary transporters that transport ions like Na⁺, K⁺, Ca⁺⁺ using ATP as a source of energy and secondary transporters that transports ions using potential energy created by the primary transporters. The sodium-potassium pump is an example of primary active transport protein and the sodium-glucose pump is an example of secondary active transport protein. They are discussed below:

Sodium potassium pump

The concentration of Na+ inside the animal cell is less whereas the concentration of K⁺ inside the animal cell is more. Sodium potassium pump releases Na+ out from the cell and releases K⁺ inside the cell. The energy required for the transport is obtained by the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP).
It participates in the transmission of nerve signals.

Sodium glucose pump

This is an example of secondary active transport which allows glucose to enter into cells. These pumps are active in intestinal and kidney cells. In both the cells, glucose moves from low concentration to high concentration. Here energy required for this transport comes from sodium ion which is created by the sodium-potassium pump.
It helps in the transport of glucose.

Metal toxicity

The toxic effects of metals in their certain forms and certain doses on the life of organisms are called metal toxicity or metal poisoning.
The toxic effects of some metals are given below:

Toxicity due to iron (Fe)

• Excess iron in the body may catalyse some reactions causing the formation of free radicals that can damage biomolecules, cells and tissue.
• Excess iron can cause the corrosion of the lining of the gastrointestinal tract that causes stomach pain and also damages the liver and brain.

Toxicity due to arsenic (As)

• The simple symptoms of arsenic poisoning are headache, diarrhoea and drowsiness.
• Excessive poisoning causes malfunctions like vomiting of blood, loss of blood in urine, cramping muscles, hair loss and stomach pain.
• Its poisoning may cause cancer of the lungs, skin, kidney and liver. It may even cause coma or death.

Toxicity due to mercury (Hg)

• Mercury poisoning causes memory loss, emotional instability and insomnia.
• During 1950, mercury poisoning killed more than 600 people in Minamata, Japan that took place due to the industrial discharge of mercury into the river. This is called Minamata disease.
• Mercury mainly attacks the brain, kidney and muscles.

Toxicity due to lead (Pb)

• Lead poisoning causes the formation of reactive oxygen species which results in health problems related to stress, a decrease in the number of antioxidants, cell damage and damage of protein.
• It also causes a headache, loss of appetite, hypertension, abdominal pain, dizziness and arthritis.

Toxicity due to cadmium

• Cadmium gets bound with some proteins and amino acids that causes deficiency of iron.
• It can cause several bone problems. Compounds of cadmium are carcinogenic.

Some Important Questions

1. What are macro and micronutrients?
2. Discuss the importance of metal ions (Na, K, Ca and Mg) in the biological system.
3. What is metal toxicity? What is the toxic effect of arsenic and mercury?
4. What do you mean by sodium-potassium and sodium-glucose pump?