Chemistry in Everyday Life Test 3

Drugs are chemicals of low molecular masses (~100u–500u) They interact with macromolceular targets and product a biological response. When the biological response is therapeutic and useful. Mize chemicals are called medicines and arc used in diagnosis. prevention and treatment of diseases. If taken in doses higher than those recommended, most of the drugs used as medicines arc potential poisons. Use of chemicals for therapeutic effect is called chemotherapy. Note : Medicine is a chemical substance which cures the disease and is safe to use it does not cause any addiction whereas drug is a chemical substance which cures disease but it causes addiction and has serious side effects. 

Pathology as a medical specialty is the branch of medicine that deals with the study of diseases and the morphologic, physiologic changes produced by them. As a diagnostic specialty, pathology can be considered the basis of modern scientific medical knowledge and plays a large role in evidence-based medicine.The branch of science that deals with the treatment of diseases using suitable chemicals is known as Chemotherapy.

Narcotics are habit forming or addictive analgesic drugs. Analgin is a non addictive analgesic.

Neurotransmitters are often referred to as the body's chemical messengers. They are the molecules used by the nervous system to transmit messages between neurons, or from neurons to muscles. Communication between two neurons happens in the synaptic cleft (the small gap between the synapses of neurons).

Aspirin (Acetyl salicylic acid) is a chemical substance which lowers body temperature and reduces pain as well. Therefore it acts both as analgesic and antipyretic.

Drugs that mimic the natural messenger by switching on the receptor, these are called agonists. These are useful when there is lack of natural chemical messenger.

An enzyme inhibitor is a molecule that binds to an enzyme and decreases its activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used in pesticides.

Drugs classified according to their chemical structure share common structural features and often have similar pharmacological activity.

Ex: All sulphonamides have a common structural feature. 

Sulphonamides are anti-bacterial drugs used to treat bacterial infections.

Drugs usually interact with bio-molecules like carbohydrates, lipids, protein and nucleic acids. These bio-molecules are called drug targets (or) simply target molecules. Drugs with similar structures have similar mechanisms of action on bio-molecular targets.

Drugs that bind to the receptor site and inhibit its natural function are called antagonists. These are useful when blocking of message is required. There are other types of drugs that mimic the natural messenger by switching on the receptor, these are called agonists. These are useful when there is lack of natural chemical messenger.

Chloramphenicol is a broad spectrum antibiotic that is derived from the bacterium Streptomyces venezuelae it interferes with mitochondrial protein synthesis and is active against a variety of organisms including salmonelloses not responsive to ampicillin.