Life Processes — Karnataka (SSLC) Class 10 Science Solutions (Free)

Life processes = vital activities that define living organisms. Five major processes: 1) Nutrition: intake and processing of food for energy/growth. 2) Respiration: breakdown of food to release energy (aerobic/anaerobic). 3) Circulation/Transport: movement of nutrients, oxygen, waste. 4) Excretion: removal of metabolic waste products. 5) Growth: increase in body size/complexity using nutrients. These processes maintain homeostasis and support all activities of life.

Nutrition = process of obtaining and utilizing food for energy and building material. Autotrophic: organisms synthesize own food using CO2 + H2O + light energy (photosynthesis in plants, chemosynthesis in bacteria). Heterotrophic: organisms cannot make food; consume ready-made organic food (animals, fungi, parasites). Autotrophs are producers (base of food chain), heterotrophs are consumers. All life depends on autotrophs for food.

Aerobic respiration = oxidation of glucose in presence of O2 to release energy (ATP). Equation: C6H12O6 + 6O2 = 6CO2 + 6H2O + energy (2830 kJ/mol). Occurs in: 1) Glycolysis: cytoplasm (glucose split into pyruvate, 2 ATP). 2) Krebs cycle: mitochondrial matrix (pyruvate oxidized, energy released). 3) Electron transport: inner mitochondrial membrane (ATP synthesized). Produces 36-38 ATP per glucose. Essential for life; occurs in most organisms.

Respiration: breaks down organic food (glucose) using O2, releases energy (exergonic, catabolic). Occurs in all living cells. Photosynthesis: builds organic food (glucose) from CO2 using light energy (endergonic, anabolic). Occurs only in green plants, algae, photosynthetic bacteria. Opposite processes: photosynthesis stores energy, respiration releases energy. Together they regulate atmospheric O2 and CO2. Plants do both; animals only respire.

Circulatory system: heart pumps blood through arteries, capillaries, veins. Three main functions of blood: 1) Transport: carries O2 from lungs to cells, CO2 from cells to lungs. 2) Nutrition: carries glucose, amino acids to cells. 3) Excretion: carries urea, excess water to kidneys for elimination. Blood also regulates body temperature, fights infection (white cells), clots (prevent bleeding). Single circulation in fish, double in mammals (pulmonary + systemic).