| Nutrient | Energy / gram | Composition | Examples / Sources | Deficiency |
|---|---|---|---|---|
| Carbohydrate | 4.1 Kcal | C : H : O = 1:2:1 | Glucose, Starch, Lactose, Fructose — Honey, Potatoes, Wheat, Fruits | Low energy |
| Protein | 4.3 Kcal | C + H + O + N + S/P | Keratin, Collagen, Haemoglobin, Casein (milk), Insulin, Gluten (wheat) — Pulses, Meat, Eggs | Marasmus & Kwashiorkor |
| Fat | 9.3 Kcal | Fatty acid + Ester of Glycerol (C, H, O) | Phospholipids, Cholesterol — Coconut, Mustard oil, Ghee, Butter, Meat | — |
| Vitamin | Chemical Name | Deficiency Disease / Effect |
|---|---|---|
| Vitamin A | Retinol [β-Carotene] | Night blindness, Xerophthalmia, stunted growth, sealing of cornea |
| Vitamin D | Calciferol | Rickets (children), Osteoporosis (adults), weakening of teeth, bones, muscles |
| Vitamin E | Tocopherol | Sterility (infertility), weak genitals and muscles |
| Vitamin K | Naphthoquinone / Phylloquinone | Excess bleeding (failure of blood clot formation) |
| Vitamin | Chemical Name | Deficiency Disease / Effect |
|---|---|---|
| B₁ | Thiamine | Beri-Beri (polished rice), carbohydrate metabolism affected |
| B₂ | Riboflavin | Cheilosis |
| B₃ | Nicotinic Acid / Niacin | Pellagra (3D) |
| B₅ | Pantothenic Acid | Skin diseases, reduced growth, graying of hair, reduced fertility |
| B₆ | Pyridoxine | Anaemia, skin disease, muscle cramps, mental illness |
| B₇ | Biotin | Skin diseases, hair loss |
| B₉ | Folic Acid | Anaemia, stunted growth, neural tube defects in newborn |
| B₁₂ | Cobalamin | Destructive anaemia, nervous system disorder, impaired RBC formation & DNA synthesis |
| C | Ascorbic Acid | Scurvy, Fe absorption affected |
| Part | Length / Shape | Key Function |
|---|---|---|
| Pharynx | 12 cm | Common passage for food and air; epiglottis prevents food entering trachea |
| Oesophagus | 22–24 cm | Peristaltic movement (pushes food down) |
| Stomach | 25 cm, J-shaped | Protein digestion, Chyme formation (pH 2.0) |
| Small intestine | Duodenum (25cm) + Jejunum (2.4m) + Ileum (3.5m) | Complete digestion + absorption by microvilli |
| Large intestine | Caecum (6cm) + Colon (1.3m) + Rectum (12–15cm) | Water absorption, faeces formation & disposal |
| Location | Gland | Key Enzymes | Acts on |
|---|---|---|---|
| Buccal cavity | Salivary gland | Ptyalin / Amylase | Starch |
| Stomach (pH 2.0) | Gastric gland (HCl + mucus) | Pepsin, Rennin, Gastric lipase | Protein, Milk protein, Fat |
| Duodenum (pH 7.5–8.2) | Pancreas | Trypsin, Chymotrypsin, Amylopsin, Carboxypeptidase, Lipase | Protein, Starch, Complex sugar, Polypeptide, Fat |
| Small intestine | Intestinal glands | Enterokinase, Erepsine, Maltase, Sucrase, Lactase, Lipase, Nuclease | Trypsinogen, Maltose, Sucrose, Lactose, Fat, Nucleotides |
| Feature | Aerobic | Anaerobic |
|---|---|---|
| O₂ | Required | Not required |
| Oxidation | Complete | Partial breakdown |
| Energy | 36 ATP (673 Kcal) | 2 ATP (27 Kcal) |
| Location | Cytoplasm + Mitochondria | Cytoplasm only |
| Products | CO₂ + H₂O | Ethanol + CO₂ (in yeast) |
| Occurs in | All autotrophic plants, most animals | Yeast, many bacteria, human muscles during exercise |
| Organism | Respiratory Surface |
|---|---|
| Amoeba and Planaria | Cell membrane |
| Earthworm and Leech | Moist skin |
| Fish, Prawns, Tadpole | Gills |
| Frog | Moist skin + Lungs (both!) |
| Mosquito and Housefly | Trachea and Spiracles |
| Birds, Lizards, Terrestrial animals | Lungs |
| Feature | RBC (Erythrocytes) | WBC (Leucocytes) | Platelets (Thrombocytes) |
|---|---|---|---|
| Number/mm³ | 4.5–5 million | 6,000–8,000 | 1,50,000–3,50,000 |
| Shape | Biconcave, round | Round or irregular | Irregular, disc-like |
| Size | 7–8 µm diameter | 12–20 µm | 2–3 µm |
| Lifespan | ~120 days | Hours to months | 8–10 days |
| Formation | Liver/Spleen (before birth), Bone marrow (after birth) | Bone marrow, lymph nodes, spleen, thymus, tonsils | Megakaryocytes of bone marrow |
| Function | O₂ & CO₂ transport | Immunity / Protection | Blood clot formation |
| Waste Type | Method of Excretion |
|---|---|
| Liquid waste | Excess water released by Transpiration through stomata |
| Gaseous waste | CO₂ and O₂ expelled through stomata and lenticles |
| Solid waste | Stored in cell vacuoles and dead cell tissues; removed by shedding leaves |
| Useful plant waste | Volatile oils, perfumes, gums, resins, natural rubber, tannin |