Chemistry in Everyday Life
Study Materials and Qs n And:
Drugs: Drugs are chemicals of low molecular masses (~100 – 500u). These interact with macromolecular targets and produce a biological response. When the biological response is therapeutic and useful, these chemicals are called medicines.
Drugs
Analgesics
Relieve or decreases the pain without causing unconsciousness. These are also known as “Pain Killers”. Asprin, Analgin, seridon, (morphine and codeine are narcotics). etc.
Tranquizers/ Antidepressants Chemical substances used for the treatment of stress, anxiety, irritability and mild or even severe mental diseases, are known as tranquilizers.
Equanil, Calmpose, Tofranil, Barbituric Acid, Cocaine and Iproniazids etc.. Noradrenaline is one of the neurotransmitter that plays a role in mood change.
Antiseptics They are applied on living tissues to kill or prevent the growth of micro-organisms. Dettol (mixture of chloroxylenol and terpineol), Savlon and Acriflavin etc.
Disinfectants These are applied on floor, instruments or wall etc. to kill microorganisms but are not safe for application on living tissues. Phenol, SO2, formaldehyde
Antimicrobial These are use to either kill (bactericidal) or stop the growth of diseases causing microorganisms. (bacteriostatic). Salvarsan, Prontosil, Sulphanilamide,
Bacteriostatic Drugs: Erythromycin, Tetracycline, Chloramphenicol
Bactericidal Drugs: Ofloxacin, Aminoglycosides.
Antipyretics These drugs bring down the body temperature during fever. Paracetamol, Analgin and Novalgin.
Antifertility Drugs Prevent pregnancy in women by controlling menstrual cycle and ovulation. Norethindrone & Mestranol
Antacids Used for the treatment of acidity.
Metal hydroxides are generally used as antacids. Eno, & Milk of magnesia [Mg(OH)2]
Antibiotics These are the chemical substances which are produced by micro –organisms like bacteria and fungi and are able to kill or stop the growth of pathogenic microorganisms. Penicillin, Amoxicillin and Ampicillin.
Antihistamins These drugs compete with histamine for finding sites of receptors and thus interfere with the natural action of histamine. Brompheniramine & Terfenadine
Food preservatives:
These are the chemical substances which prevent undesirable changes in flavor, colour, texture of the food during processing and storage of food.
Examples, Table salt, sugar, vegetable oils, sodium benzoate (C6H5COONa) etc
Questions
Q1. Explain the term target molecules or drug targets as used in medicinal chemistry.
Ans. In medicinal chemistry, drug targets refer to the key molecules involved in certain metabolic pathways that result in specific diseases. Carbohydrates, proteins, lipids, and nucleic acids are examples of drug targets. Drugs are chemical agents designed to inhibit these target molecules by binding with the active sites of the key molecules.
Q2. Low level of noradrenaline is the cause of depression. What types of drugs are needed to cure this problem? Name two drugs.
Ans. Anti-depressant drugs are needed to counteract the effect of depression. These drugs inhibit enzymes catalysing the degradation of the neurotransmitter, noradrenaline. As a result, the important neurotransmitter is slowly metabolised and then it can activate its receptor for longer periods of time.
Two anti-depressant drugs are:
(i) Iproniazid
(ii) Phenelzine
Q3. What is meant by the term ‘broad spectrum antibiotics’? Explain.
Ans. Antibiotics that are effective against a wide range of gram-positive and gram-negative bacteria are known as broad spectrum antibiotics. Chloramphenicol is a broad spectrum antibiotic.
Q4. How do antiseptics differ from disinfectants? Give one example of each.
Ans. Antiseptics and disinfectants are effective against micro-organisms. However, antiseptics are applied to the living tissues such as wounds, cuts, ulcers, and diseased skin surfaces, while disinfectants are applied to inanimate objects such as floors, drainage system, instruments, etc. Disinfectants are harmful to the living tissues.
Iodine is an example of a strong antiseptic. Tincture of iodine (2 – 3 percent of solution of iodine in alcohol – water mixture) is applied to wounds. 1 percent solution of phenol is used as a disinfectant.
Q5. Name a substance which can be used as an antiseptic as well as disinfectant.
Ans. Phenol can be used as an antiseptic as well as a disinfectant. 0.2 percent solution of phenol is used as an antiseptic, while 1 per cent of its solution is used as a disinfectant.
Q6. What is tincture of iodine? What is its use?
Ans. Tincture of iodine is a 2 – 3 percent solution of iodine in alcohol – water mixture. It is applied to wounds as an antiseptic.
Q7. Why is use of aspartame limited to cold foods and drinks?
Ans. Aspartame becomes unstable at cooking temperature. This is the reason why its use is limited to cold foods and drinks.
Q8. What are artificial sweetening agents? Give two examples.
Ans. Artificial sweetening agents are chemicals that sweeten food. However, unlike natural sweeteners, they do not add calories to our body. They do not harm the human body. Some artificial sweeteners are aspartame, saccharin, sucrolose, and alitame.
Q9. How are synthetic detergents better than soap?
Ans. Soaps work in soft water. However, they are not effective in hard water. In contrast, synthetic detergents work both in soft water and hard water. Therefore, synthetic detergents are better than soaps.
Q10. Can you use soaps and synthetic detergents to check the hardness of water?
Ans. Soaps get precipitated in hard water, but not in soft water. Therefore, soaps can be used for checking the hardness of water.
However, synthetic detergents do not get precipitated either in hard water or in soft water. Therefore, synthetic detergents cannot be used for checking the hardness of water.
Q11. Explain the cleansing action of soaps.
Ans. Soap molecules form micelles around an oil droplet (dirt) in such a way that the hydrophobic parts of the stearate ions attach themselves to the oil droplet and the hydrophilic parts project outside the oil droplet. Due to the polar nature of the hydrophilic parts, the stearate ions (along with the dirt) are pulled into water, thereby removing the dirt from the cloth.
Q12. Why do soaps not work in hard water?
Ans. Soaps are sodium or potassium salts of long-chain fatty acids. Hard water contains calcium and magnesium ions. When soaps are dissolved in hard water, these ions displace sodium or potassium from their salts and form insoluble calcium or magnesium salts of fatty acids. These insoluble salts separate as scum.
This is the reason why soaps do not work in hard water.
Q13. Why the receptors embedded in cell membrances show selectivity for one chemical messenger over the other?
Ans : The active site of receptor has specific shape and specific functional groups which can bind only specific messenger which fits in.
Q14. With reference to which classification has the statement ‘ranitidine is an antacid’ been given?
Ans : Classification based on pharmacological effect.]
Q15. Give the name of medicine used for the treatment of syphilis.
Ans : Salvarsan.
Q16. How does aspirin act as analgesic?
Ans: Aspirin inhibits the synthesis of prostaglandins which cause pain.
Q17. What are barbiturates? What is the action of barbiturates on human body?
Ans : Barbaturic acid derivatives are called barbiturates. They are highly effective pain relieving agents.
Q18. Name the antiseptic agents present in dettol.
Ans : Chloroxylenol and Terpineol.
Q19. What precaution should be taken before administrating penicillin to a patient?
Ans : To confirm, beforehand that the patient is not allergic to penicilin.
Q20. Explain why aspirin finds use in prevention of heart attacks?
Ans : Due to anti blood clotting activity.
Q21. Mention one use of drug meprobamate.
Ans : Antidepressant drug.
Q22. Why synthetic detergents are preferred over soaps for use in washing machines?
Ans : They work well even with hard water and not form any scum.
Q23. How is acidity cured with cimetidine?
Ans: Cimetidine prevents the interaction of histamines with the receptors present in stomach wall.
Q24. While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?
Ans: Antacids and antiallergic drugs bind to the different receptor sites. Therefore, they do not interfere with the function of each other.
Q25. If water contains dissolved calcium hydrogencarbonate, which out of soap and detergent, will you prefer to use? Why?
Ans: We will use detergent because it will not form insoluble precipitate with Ca2+.
Q26. Pick out the odd one amongst the following on the basis of their medicinal properties. Give suitable reason.
(i) Luminal, seconal, terfenadine, equanil.
(ii) Chloroxylenol, phenol, chloamphenicol, bithional.
(iii) Sucralose, aspartame, alitame, sodium benzoate.
Ans :(i) Terfenadine is antihistamine other three are used as tranquilisers.
(ii) Chloramphenicol is a broad spectrum antibiotic. Other three have antiseptic properties.
(iii) Sodium benzoate is a food preservative. Other three are artificial sweetners.
Q27. How do enzyme inhibitors work? Distinguish between competitive and noncompetitive enzyme inhibitors.
Ans : An enzyme inhibitor either blocks the active site of enzyme or changes the shape of the active site by binding at an allosteric site. They are of two types.
(i) Competitive enzyme inhibitor – It competes with natural substance for their attachment on the active sites of enzymes.
(ii) Non-competitive enzyme inhibitor binds at allosteric site and changes the shape of the active site in such a way that the substrate cannot recognise it.
Some Other Questions with Answers
Q. 1. When a mixture of salicylic acid, acetic anhydride and acetic acid is refluxed, what is the product obtained and what is its use in everyday life ?
Ans. Aspirin used as analgesic.
Q. 2. Distinguish between a narrow spectrum and broad spectrum antibiotic.
Ans. A narrow spectrum antibiotic works against a limited range of microbes whereas a broad spectrum antibiotic works against a large variety of microbes.
Q. 3. What is Salvarson ? To which class of drugs does it belong ? For what disease is it used ?
Ans. Antimicrobial agent.
Used for the treatment of STD called Syphilis.
Q. 4. How does apirin act as an analgesic ?
Ans. It inhibits the synthesis of prostaglandins which stimulates inflammation of the tissue and cause pain.
Q. 5. What are barbiturates ? To which class of drugs do they belong ?
Ans. 5, 5-derivatives of barbituric acid are called barbiturates. They belong to the class of tranquilizers. They also act as sleep producing agents.
Eg. Luminal, Veronal.
Q. 6. What is tincture iodine ? What is its use ?
Ans. 2-3% solution of iodine in alcohol, which is a powerful antiseptic for wounds.
.
Q. 7. To what class of medicines does chloramphericol belong ? For what disease can it be used ?
Ans. Broad spectrum antibiotic
Used to cure typhoid, dysentry, acute fever.
Q. 8. Pick the odd one amongst the following on the basis of their medicinal properties mentioning the reason.
(i) Luminal, seconal, phenacetin, equanil
(ii) Chloroxylenol, phenol, chlorampherical, bithional
Ans. (i) Phenacetin is an antipyretic while all the rest are tranquilisers.
(ii) Chlorampherical is an antibiotic while all the remaining are antiseptics.
Q. 9. Why is bithional added to soap ?
Ans. Acts as an antiseptic and reduces the odours produced by bacterial decomposition of organic matter on the skin.
Q. 10. Why are cimetidine or ranitidine better antacids than sodium bicarbonate or magnesium or aluminium hydroxide ?
Ans. If excess of NaHCO3 or Mg(OH)2 or Al(OH)3 is used, it makes the stomach alkaline and thus triggers the release of even more HCl. In contrast, cimetidine or ranitidine prevent the interaction of histamine with the receptor cells in the stomach wall and thus release lesser amount of HCl.
Q. 11. Why is the use of aspartame limited to cold foods and drinks ?
Ans. It decomposes at baking or cooking temperatures and hence can be used only in cold foods and drinks.
Q. 12. What problem arises in using alitane as artificial sweetener?
Ans. It is a high potency artificial sweetener. Therefore it is difficult to control the sweetness of the food to which it is added.
Q. 13. What is the purpose of adding antioxidants to food ? Give two examples of antioxidants.
Ans. They are added to prevent oxidation of fats and oils present in food thus preventing food from becoming rancid.
Eg. BHA (Butylated hydroxy anisole), BHT (Butylated hydroxy toluene)
Q. 14. Give an example of a chemical substance which can act both as an antiseptic and disinfectant.
Ans. Phenol.
Q. 15. What is the chemical name of antiseptic chloroxylenol ?
Ans. 4-Chloro-3, 5-dimethyl phenol.
Q. 16. Which alkaloid is used to control hypertension ?
Ans. Reserpine.
Q. 17. Which alkaloid is used to treat malaria ?
Ans. Quinine.
Q. 18. Which artificial sweetner has the lowest sweetness value ?
Ans. Aspartame.
Q. 19. Which artificial sweetner has the highest sweetness value ?
Ans. Alitame.
Q. 20. What kind of a drug is Chlorpheniramine maleate ?
Ans. Anti histamine drug.
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