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Biology · Class 10 · Chapter 18: Pharmacology

8 min

Key points

Pharmacology is the branch of biology that deals with the study of drugs, their sources, properties, effects on living organisms and their therapeutic uses
Drugs are chemical substances that affect the structure and function of living organisms when introduced into the body
Drug sources include plants (digitalis from foxglove), animals (insulin from pancreas), minerals (iron supplements), and synthetic sources
Drug classification includes stimulants (increase nervous system activity), depressants (decrease nervous system activity), hallucinogens (alter perception), and therapeutic drugs
Antibiotics are substances produced by microorganisms that kill or inhibit the growth of other microorganisms — discovered by Alexander Fleming
Drug abuse refers to the excessive and harmful use of drugs that leads to physical and psychological dependence
Tolerance occurs when the body requires increasingly larger doses of a drug to achieve the same effect
Withdrawal symptoms appear when a drug-dependent person stops taking the drug suddenly

Definitions

Pharmacology: The branch of biology that deals with the study of drugs, their sources, properties, effects on living organisms and their therapeutic uses
Drug: A chemical substance that affects the structure and function of living organisms when introduced into the body
Antibiotic: A substance produced by microorganisms that kills or inhibits the growth of other microorganisms
Drug Abuse: The excessive and harmful use of drugs that leads to physical and psychological dependence
Tolerance: A condition in which the body requires increasingly larger doses of a drug to achieve the same effect

Worked example

Define pharmacology. Classify drugs on the basis of their action and give one example of each type. (5 marks)

Pharmacology is the branch of biology that deals with the study of drugs and their effects on living organisms. Classification: (1) Antibiotics - drugs that kill or inhibit the growth of bacteria, e.g., Penicillin (2) Analgesics - drugs that relieve pain, e.g., Aspirin (3) Vaccines - biological preparations that provide immunity against diseases, e.g., Polio vaccine

Common mistakes

Students often confuse drug tolerance with drug resistance
Writing incomplete definitions without mentioning 'effects on living organisms'
Forgetting to mention Alexander Fleming when discussing antibiotic discovery
Confusing stimulants with depressants - remember caffeine is stimulant, alcohol is depressant
Not writing sources of drugs with proper examples in answers

Quick recap

Pharmacology studies drugs and their effects on living organisms. Drugs are classified as antibiotics (kill bacteria - Penicillin), analgesics (relieve pain - Aspirin), and vaccines (provide immunity - Polio vaccine). Sources include plants (Digitalis), animals (Insulin), and minerals (Calomel). Always write textbook-exact definitions for full marks.

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