Diseases and Nutrition
Subject: General Science — Biology | Topic: Diseases and Nutrition Exam: AP Group 2 (APPSC) | Sources: NCERT Class IX, Lucent's GS
Introduction
This is one of the highest-yield topics — expect 3-4 questions. Disease-pathogen matching, vitamin deficiency diseases, and vector-borne diseases are APPSC staples. Memorise the vitamin table and disease-vector table for guaranteed marks.
Classification of Diseases
| Type | Cause | Spread | Examples |
|---|---|---|---|
| Infectious (Communicable) | Pathogens | Person to person | TB, Malaria, COVID-19 |
| Non-infectious | Not pathogens | Cannot spread | Diabetes, Cancer, Heart disease |
| Acute | — | Short duration, sudden | Cold, Flu, Cholera |
| Chronic | — | Long duration, slow | Diabetes, TB, Cancer |
Disease-Causing Organisms
| Pathogen | Diseases |
|---|---|
| Bacteria | Cholera (Vibrio cholerae), TB (Mycobacterium), Typhoid (Salmonella typhi), Plague, Leprosy, Pneumonia, Tetanus, Diphtheria |
| Viruses | Common cold, Influenza, Dengue, COVID-19 (SARS-CoV-2), AIDS (HIV), Rabies, Polio, Measles, Hepatitis, Chickenpox |
| Protozoa | Malaria (Plasmodium/Anopheles mosquito), Amoebic dysentery, Kala-azar (sandfly), Sleeping sickness (tsetse fly) |
| Fungi | Ringworm, Athlete's foot |
| Worms | Roundworm (Ascaris), Tapeworm, Filariasis/Elephantiasis (Culex mosquito) |
Modes of Transmission
| Mode | Examples |
|---|---|
| Air-borne | Cold, TB, Influenza, COVID-19 |
| Water-borne | Cholera, Typhoid, Hepatitis A, Dysentery |
| Vector-borne | Malaria (Anopheles), Dengue (Aedes), Plague (rat flea), Kala-azar (sandfly) |
| Contact/Sexual | AIDS, Syphilis, Gonorrhoea |
| Animal bites | Rabies (dog/bat bite) |
Immunity and Vaccination
| Type | Mechanism | Duration |
|---|---|---|
| Innate/Natural | Present from birth; skin, mucus, WBCs | Permanent |
| Active (Acquired) | Body produces own antibodies (infection or vaccine) | Long-lasting |
| Passive (Acquired) | Ready-made antibodies given (mother's milk, anti-venom) | Short-term |
Important vaccines: BCG (TB), OPV (Polio), DPT (Diphtheria, Pertussis, Tetanus), MMR (Measles, Mumps, Rubella), Hepatitis B. COVID-19: Covishield, Covaxin (Bharat Biotech — India's indigenous).
Antibiotics kill bacteria, NOT viruses. Antibiotic resistance from overuse is a major health concern.
Vitamins
| Vitamin | Chemical Name | Sources | Deficiency Disease |
|---|---|---|---|
| A | Retinol | Carrot, liver, eggs | Night blindness, Xerophthalmia |
| B1 | Thiamine | Whole grains, legumes | Beriberi |
| B2 | Riboflavin | Milk, eggs | Cheilosis (cracked lips) |
| B3 | Niacin | Meat, peanuts | Pellagra (3 Ds: Dermatitis, Diarrhoea, Dementia) |
| B12 | Cobalamin | Meat, fish, dairy | Pernicious anaemia |
| C | Ascorbic acid | Citrus, amla, guava | Scurvy (bleeding gums) |
| D | Calciferol | Sunlight, fish oil | Rickets (children), Osteomalacia (adults) |
| E | Tocopherol | Vegetable oils, nuts | Sterility, muscle weakness |
| K | Phylloquinone | Green leafy vegetables | Excessive bleeding (needed for clotting) |
Fat-soluble: A, D, E, K. Water-soluble: B-complex, C.
Minerals
| Mineral | Function | Deficiency | Sources |
|---|---|---|---|
| Iron | Haemoglobin formation | Anaemia | Spinach, liver, jaggery |
| Calcium | Bones and teeth | Osteoporosis | Milk, cheese, ragi |
| Iodine | Thyroid hormones | Goitre, Cretinism | Iodised salt, seafood |
Macronutrients
| Nutrient | Energy | Function | Sources |
|---|---|---|---|
| Carbohydrates | 4 kcal/g | Primary energy | Rice, wheat, potato |
| Proteins | 4 kcal/g | Body building, repair | Pulses, eggs, milk |
| Fats | 9 kcal/g | Concentrated energy | Oil, butter, nuts |
Protein deficiency: Kwashiorkor (swollen belly), Marasmus (severe wasting).
Likely Exam Questions
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Malaria is caused by ___ and spread by ___: Ans: Plasmodium (protozoa); female Anopheles mosquito
-
Dengue fever is spread by: Ans: Aedes aegypti mosquito
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Vitamin C deficiency causes: Ans: Scurvy (bleeding gums, weakness)
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Rickets in children is caused by deficiency of: Ans: Vitamin D
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India's indigenous COVID-19 vaccine is: Ans: Covaxin (by Bharat Biotech)
-
The disease caused by deficiency of iron is: Ans: Anaemia
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Pellagra is caused by deficiency of: Ans: Vitamin B3 (Niacin)
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Antibiotics are effective against: Ans: Bacteria (NOT viruses)
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Kwashiorkor is caused by deficiency of: Ans: Protein
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Fat provides how many kilocalories per gram? Ans: 9 kcal/g