 What is metabolism? The sum of all chemical reactions occurring in the body.  Why do we need all those chemical reactions? There are lots of jobs that must be done to keep us alive! Breathing, digestion, movement, thinking, immunity, growth, etc.  All those reactions require energy. Where do we get the energy from?

(stored in glucose) (wasted energy) (wasted) (Used for Movement)

 1 st Law: Energy cannot be created or destroyed, but it can change from one form to another. Solar, chemical, mechanical, heat energy, etc.  2 nd Law: When energy changes forms, some of the energy is wasted or lost as… HEAT!

Spot the Dog Chemical energy is stored in each of these covalent bonds.

 Solar energy + 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 (carbon (water) (glucose) (oxygen) dioxide)  Photosynthesis transforms solar energy into the chemical energy of a carbohydrate.  The photosynthetic process takes place with organelles called chloroplasts.

 Energy for cells is stored in the chemical bonds of organic molecules (lipids, proteins and carbohydrates)  These are the “fuels” that power organisms  The carbohydrate “glucose” is the primary source of energy for the cell  C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O +ATP (Cellular Respiration)

 Adenosine Triphosphate nucleotideVery high energy bonds between phosphate groups

 ATP directly supplies the energy necessary for nearly all chemical reactions in the body.  Chemical energy is stored in the high energy bonds that hold the phosphate groups together in the ATP molecule.  When ATP is broken down, a phosphate group is released along with free energy that can be used for metabolism.

 ATP is the energy-carrier molecule in all cells  Think of ATP like a rechargeable battery  The battery “releases” its energy to run a radio/flashlight. (ATP ADP)  When its energy has been used the battery has to be recharged by adding energy to it (ADP + P ATP)

 What are carbs and why do we always refer to them when discussing Cellular Respiration?!?!  How do we go from eating a sandwich to using the glucose to create usable energy for our cells?

 Chemical work: ATP supplies the energy needed to build organic molecules in the cell.  Transport work: ATP supplies the energy to pump substances across the cell membrane.  Mechanical work: ATP provides energy for movement. (muscle contraction, flagella, chromosome movement during mitosis, etc.)

 Organisms require energy for metabolism.  That energy ultimately comes from the sun’s energy stored in the chemical bonds of glucose, produced by photosynthesis. (We eat plants/glucose)  Mitochondria within cells have the machinery necessary to turn that glucose into ATP that the cell can use for energy.

The products of photosynthesis (sugar and oxygen) are used by cells during respiration. The by-products of respiration (carbon dioxide and water) are used by cells performing photosynthesis. And so it continues, with sunlight being put in as energy at the photosynthesis stage, and cellular energy (ATP) derived from glucose at the respiration stage.

and water Cellular Respiration Photosynthesis and water In process of making ATP for cow

 Given a hundred trillion cells in the average male, about or one sextillion ATP molecules normally exist in the body. For each ATP “the terminal phosphate is added and removed 3 times each minute” (Kornberg, 1989).