How Do Biological Organisms Use Energy? The Importance of ATP All organisms use a two-step process to provide the energy needed for most of their biological activities: First, chemical energy from organic molecules like glucose is used to make ATP. This process is called cellular respiration. Then, ATP provides the energy for most biological processes. These two steps are illustrated in the figures. First, energy from cellular respiration is used to make ATP (adenosine triphosphate, with 3 phosphates) from ADP (adenosine diphosphate, with 2 phosphates) plus a phosphate. (Figures from Belk and Borden, Biology: Science for Life, 2007) The reverse reaction (breakdown of ATP to ADP and a phosphate) releases energy which is used for many different cellular processes. Questions 1. Explain why the reaction, ADP + phosphate -- > ATP, requires energy (Hint: Review the top figure on the previous page and remember that opposite charges repel each other.) 2. Explain why all biological organisms need to carry out the reaction, ATP -- > ADP + phosphate. How is this reaction useful? Using Energy from Organic Molecules to Make ATP -- Cellular Respiration Cellular respiration is the process that transfers some of the chemical energy in glucose or another organic molecule to chemical energy in ATP molecules. Cellular respiration is a complex process with many steps. The following two chemical equations give a simplified overview of the cellular respiration of glucose to produce ATP. C6 H12O6 + 6 O2 --------> 6 CO2 +6 H2O \/ energy \/
How Do Biological Organisms Use Energy? The Importance of ATP All organisms use a two-step process to provide the energy needed for most of their biological activities: First, chemical energy from organic molecules like glucose is used to make ATP. This process is called cellular respiration. Then, ATP provides the energy for most biological processes. These two steps are illustrated in the figures. First, energy from cellular respiration is used to make ATP (adenosine triphosphate, with 3 phosphates) from ADP (adenosine diphosphate, with 2 phosphates) plus a phosphate. (Figures from Belk and Borden, Biology: Science for Life, 2007) The reverse reaction (breakdown of ATP to ADP and a phosphate) releases energy which is used for many different cellular processes. Questions 1. Explain why the reaction, ADP + phosphate -- > ATP, requires energy (Hint: Review the top figure on the previous page and remember that opposite charges repel each other.) 2. Explain why all biological organisms need to carry out the reaction, ATP -- > ADP + phosphate. How is this reaction useful? Using Energy from Organic Molecules to Make ATP -- Cellular Respiration Cellular respiration is the process that transfers some of the chemical energy in glucose or another organic molecule to chemical energy in ATP molecules. Cellular respiration is a complex process with many steps. The following two chemical equations give a simplified overview of the cellular respiration of glucose to produce ATP. C6 H12O6 + 6 O2 --------> 6 CO2 +6 H2O \/ energy \/
clarification_on_misconceptions_about_cellular_respiration-1.docx