This chapter explains how living organisms carry out essential activities that are necessary to maintain life. It describes life processes such as nutrition, respiration, transportation, and excretion, which continue even when an organism is at rest. The chapter highlights how these processes provide energy, maintain internal balance, and remove waste materials. It explains differences in life processes among plants and animals, unicellular and multicellular organisms, and shows how specialised organs and tissues work together to keep the body alive and functioning efficiently.
Key Points
Life processes are activities needed to maintain life.
Living organisms show internal molecular movement, even if no visible movement is seen.
Nutrition provides energy and raw materials for growth and repair.
Autotrophic nutrition occurs in green plants through photosynthesis.
Photosynthesis uses carbon dioxide, water, sunlight, and chlorophyll to make food.
Heterotrophic nutrition depends on other organisms for food.
Animals show different feeding methods such as holozoic, parasitic, and saprophytic nutrition.
Digestion in humans occurs in the alimentary canal, with the help of enzymes.
Respiration releases energy from food.
Aerobic respiration uses oxygen and releases more energy.
Anaerobic respiration occurs without oxygen and releases less energy.
Transportation moves food, oxygen, hormones, and wastes in the body.
The heart, blood, and blood vessels form the human transport system.
Plants use xylem to transport water and minerals.
Plants use phloem to transport food by translocation.
Excretion removes harmful metabolic wastes from the body.
Kidneys filter blood and form urine using nephrons.
Plants remove wastes through transpiration, storage, and shedding leaves.
👉 👉Life depends on continuous and well-coordinated processes. Understanding life processes helps us appreciate how our body and plants function efficiently and reminds us to maintain a healthy lifestyle and protect living systems responsibly.