life processes

• Life processes are the processes that perform maintenance functions in living organisms even when they are not actively doing anything
• Energy is needed for these maintenance processes to prevent damage and breakdown
• Energy for life processes comes from outside the body of the organism
• The process of transferring energy from outside the body to the inside is called nutrition
• Additional raw material from outside is needed for the growth of the body size of organisms
• Most food sources for organisms are carbon-based
• Different organisms use different nutritional processes depending on the complexity of the carbon sources
• Outside sources of energy need to be broken down or built up in the body and converted to a uniform source of energy for various molecular movements and growth
• Chemical reactions in the body, such as oxidising-reducing reactions, are necessary to break down molecules
• Many organisms use oxygen sourced from outside the body for oxidising-reducing reactions
• The process of acquiring oxygen from outside the body and using it in the breakdown of food sources for cellular needs is called respiration
• In multi-cellular organisms, specialised tissues are needed for the uptake of food and oxygen
• A transportation system is required in multi-cellular organisms to carry food and oxygen from one place to another in the body
• Waste byproducts created from chemical reactions in the body need to be removed and discarded outside the body by a process called excretion