Nutrition — Telangana (SSC) Class 10 Science Solutions (Free)

Nutrition: Process of intake and utilization of food for energy, growth, and maintenance. Classification of nutrients: 1. Carbohydrates (glucose, starch) - energy source 2. Proteins (amino acids) - growth, enzymes, antibodies 3. Lipids/Fats - energy storage, insulation 4. Vitamins - regulating metabolic processes 5. Minerals - building bones, enzymes 6. Water - solvent, temperature regulation 7. Fiber - digestion aid Autotrophs vs Heterotrophs: Autotrophs: Produce their own food (plants, algae); require only inorganic materials + sunlight/chemicals Heterotrophs: Cannot produce food; consume other organisms (animals, fungi); require organic nutrients Plants = autotrophs (photosynthesis); animals = heterotrophs

Photosynthesis: Process by which plants convert light energy into chemical energy (glucose) using CO₂ and water. Balanced equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in presence of chlorophyll and sunlight) Raw materials (inputs): 1. Carbon dioxide (CO₂) - from air, enters through stomata 2. Water (H₂O) - from soil, absorbed by roots 3. Sunlight - energy source Products (outputs): 1. Glucose (C₆H₁₂O₆) - organic food, stored in plant 2. Oxygen (O₂) - released during light reactions, used by plants and animals Two stages: 1. Light reactions (thylakoids): Light energy → ATP + NADPH + O₂ 2. Dark reactions (stroma): ATP + NADPH + CO₂ → Glucose

Significance of photosynthesis: For plants: 1. Produces glucose → energy for growth, maintenance, reproduction 2. Produces oxygen as byproduct 3. Stores solar energy in chemical bonds (sustainable energy source) 4. Basis of all plant tissues and biomass For animals and ecosystems: 1. Produces oxygen → essential for respiration of all aerobic organisms 2. Produces food (glucose) → primary energy source for food chains 3. Creates biodiversity: plants → herbivores → carnivores 4. Food chains depend on photosynthetic capacity For Earth: 1. Maintains atmospheric oxygen levels (~21%) 2. Removes CO₂ → reduces greenhouse gases 3. Produces fossil fuels (coal, oil, gas) from ancient plants 4. Supports all life on Earth

Heterotrophic nutrition: Organisms cannot synthesize food; must consume organic matter from plants/animals. Human digestive system organs and functions: 1. Mouth: Mechanical digestion (teeth chew); chemical digestion (saliva contains amylase → breaks starch) 2. Esophagus: Transports food via peristalsis 3. Stomach: Secretes HCl + pepsin → breaks proteins into peptides; churns food 4. Small intestine (duodenum, jejunum, ileum): Main site of digestion; bile + pancreatic enzymes; nutrient absorption via villi 5. Pancreas: Secretes enzymes (amylase, protease, lipase) + bicarbonate 6. Liver: Produces bile → emulsifies fats 7. Large intestine: Absorbs water + minerals; stores waste 8. Rectum + Anus: Expels feces

Enzymes in digestion: Carbohydrate digestion: 1. Salivary amylase (saliva) → breaks starch into maltose (mouth) 2. Pancreatic amylase (small intestine) → starch to maltose 3. Maltase (intestinal enzyme) → maltose to glucose Protein digestion: 1. Pepsin (stomach) + HCl → proteins to peptides 2. Trypsin (pancreas) → peptides to smaller peptides 3. Peptidases (intestinal) → peptides to amino acids Fat digestion: 1. Bile salts (liver) → emulsify fats into smaller droplets (not enzyme, but important) 2. Lipase (pancreas) → breaks triglycerides into fatty acids + glycerol 3. Phospholipase (pancreas) → breaks phospholipids Location of main digestion: Small intestine (duodenum)

Structure of villus: • Small finger-like projection (0.5-1.5 mm) from small intestine wall • Contains: epithelial cells, blood capillaries, lymph vessel (lacteal) • Brush border: microscopic microvilli on epithelial cells Adaptations for absorption: 1. Large surface area: • Many villi (30,000+) in small intestine • Microvilli on villus cells → total area ~200-400 m² (like tennis court!) 2. Rich blood supply: • Capillary network brings away absorbed nutrients • Oxygen for active transport 3. Single cell layer: • Epithelial cells thin → short diffusion distance • Facilitates rapid nutrient passage 4. Lacteal vessel: • Absorbs fatty acids + glycerol (fats) • Transports to bloodstream via lymphatic system 5. Active transport cells: • Mitochondria provide ATP for active absorption

Nutrition in plants: Plants are autotrophs → produce organic food via photosynthesis But require minerals (inorganic nutrients) for healthy growth How plants obtain nitrogen: 1. From soil (nitrates NO₃⁻, ammonium NH₄⁺) → absorbed by roots 2. Nitrogen fixation: Some plants (legumes) host nitrogen-fixing bacteria in root nodules • Bacteria convert atmospheric N₂ → NH₃ → plant-usable form • Example: Pea, bean, clover 3. Animal manure, fertilizers → decomposed to nitrates Mineral deficiency symptoms: 1. Nitrogen deficiency: Yellowing of older leaves first; stunted growth; pale color 2. Phosphorus deficiency: Purple/reddish color; poor root development 3. Potassium deficiency: Yellow leaf margins; weak stems; poor fruit quality 4. Iron deficiency: Yellowing of young leaves (chlorosis); interveinal yellowing 5. Magnesium deficiency: Interveinal chlorosis; pale color