ENERGY USE IN LIVING THINGS



The relationship between life and energy is complex--from cells to entire populations! Energy flows through the environment beginning with energy from sunlight. This energy is transformed and moved from one location to another, BUT it does NOT disappear! Plants capture the sunlight energy and use it to power the process of photosynthesis. Through the process of photosynthesis energy rich food molecules are made. These food particles serve as energy sources for the producers, and ultimately, the consumers.

The chemical process of photosynthesis converts light energy from the sun into the bond energy of food particles (carbohydrates--sugars, fats / lipids, and proteins). Only organisms with chlorophyll--the green chemical that can use the sunlight's energy--are capable of completing the process of photosynthesis. All living things are dependent upon these chlorophyll containing cells for the first step in the flow of energy from the sun.

The light energy which has been converted into rich, chemical food particles needs to be converted again into small energy molecules. IMAGINE trying to pay for a taco at TACO BELL by giving the cashier your car, and then asking for change! Certainly, the cashier would be glad to receive your car, BUT your car is too large a monetary asset for such an exchange! AND if you pulled up to the drive through window, how would you get the car inside??? It is probably NOT going to fit. Like wise, the cells of consumers and producers need to have the rich, complex food particles made in the process of photosynthesis, broken down small enough to enter their cell membranes for the next energy conversion. Many organisms use the process of digestion to break down food particles that result from photosynthesis.

Once the rich, food particles are broken down, they enter the cells of consumers and producers. A chemical process called respiration releases stored molecular energy so that it can be used for the life processes of the cell. Both producers and consumers respire. As a result, multicellular organisms maintain stable internal body systems--circulatory, excretory, endocrine, immune to name a few...