Renascent Systems, teaching about NADH - Life's Energy Source
   |
| + + + Renascent Systems, teaching about NADH - Life's Energy Source |
|
 |
|
|
|
|
|||||||||||||||||||
|
Glucose is changed into Energy . . . to the previous page  The amount of energy in each chemical bond is not the same. Some
bonds have more energy packed into them than others. The cell gets its warmth and its
energy for work from the breaking of the bonds of glucose molecules. Cells have a
complicated set of enzymes and coenzymes for the step-by-step whittling of bonds
of the glucose molecule and the step-by-step release of energy from these bonds. NADH is
the coenzyme that plays the primary role in the release of energy.Some of these steps are well known, and the overall picture is clear. The bonds in glucose are broken one at a time, and phosphates (salts containing phosphorus) play an important role in the process. Phosphate molecules store much of the released energy in a form more useful to the cell. The howling wind has a lot of energy. The farmer's windmill catches some of that energy and at once puts it to work pumping water from a well. But some of that energy is also stored by the charging of batteries. The wind cannot light up the farmer's house, but the battery can. The heat from a crumbling glucose molecule does not make our legs move. It is the energy in the phosphate bond that supplies the energy that makes the muscles move. Phosphate bonds are our batteries. They are the stored energy for life's every need. How does it work, this marvelous battery to which we owe our lives? The battery is a molecule - a molecule called adenosine triphosphate - abbreviated as ATP. Onto one molecule of ATP are lashed two, special phosphate groups. Ten calories of energy are packed into each of those bonds which hold these phosphates to the ATP. These phosphate cementing calories are the main form of energy the cell can use for its many tasks. |
|||||||||||||||||||||
 |
How stored phosphate-bond energy is used in
our body's muscles This stored phosphate-bond energy is used in a remarkable manner. Suppose a muscle cell needs ten calories of energy to set off a muscle contraction. A unit of ATP is alerted to act by an agent, called a coenzyme, which splits off one phosphate unit and then delivers the required ten calories. In the process, the ATP is reduced to ADP (adenosine diphosphate). If the energy set free by the splitting off of phosphate units is not used for muscle contraction, it can be transferred to the other compounds in the muscle such as creatine and glucose. In so doing, the glucose is taken from a glycogen storage depot and begins to be broken down. The energy flowing from the crumbling glucose is used to furnish heat, convert some of the broken-down glucose back to glucose, and attach the liberated phosphate units to ADP to reform ATP. When this cycle is completed, the ATP units are ready for any new emergency. The ready supply of the stored ATP energy for movement is marvelously useful to all animals in emergencies. Sometimes an animal needs enormous amounts of energy when there is not enough time to break down glucose. After a vigorous sprint to the bus a person may pant for minutes before they can settle down to the calm reading of the morning paper. The panting is the body's way of taking in large amounts of oxygen needed for the burning of glucose to build back the ATP used up by the exertion of hurrying to the bus. . . . continued on the next page |
|
|
|
|
|
|
 |
|
|
 |
©1996-2008_Renascent_Systems_Inc_All_rights_reserved_Rev01/2008 |