All organisms use energy to carry out the functions of life. Originally, this energy usually comes from the sun. Photosynthetic autotrophs, such as plants and algae, absorb sunlight energy and convert it into chemical energy (organic compounds).
Most foods contain usable energy, stored in organic molecules such as proteins, carbohydrates and fats. All cells break down these organic molecules into simpler molecules, releasing energy that can be stored in ATP. ATP is used to power all cellular activity.
Objective: Identify the reactants, products, and basic purposes of photosynthesis and cellular respiration. Explain the interrelated nature of photosynthesis and cellular respiration in the cells of photosynthetic organisms. Std. 2.4
Objective: Explain the important role that ATP serves in metabolism. Std. 2.5