Energy charge
Encyclopedia
Energy charge is an index used to measure the energy status of biological cells
. It is related to ATP
and ADP
concentrations and its value effects rates of metabolism
.
From Stryer:
A high energy charge signals the slow down of metabolism.
A low energy charge signals up regulation of metabolism.
this text helps me for my class test thangs.
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
. It is related to ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
and ADP
Adenosine diphosphate
Adenosine diphosphate, abbreviated ADP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside adenosine. ADP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase adenine....
concentrations and its value effects rates of metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
.
From Stryer:
"Many reactions in metabolism are controlled by the energy status of the cell. One index of the energy status is the energy charge, which is proportional to the mole fraction of ATP plus half the mole fraction of ADP, given that ATP contains two anhydride bonds whereas ADP contains one. Hence the energy charge is defined as:
The energy charge can have a value ranging from 0 (all AMP) to 1(all ATP). Daniel Atkinson showed that ATP-generating (catabolic) pathways are inhibited by a high energy charge. In plots of the reaction rates of such pathways versus the energy charge, the curves are steep near an energy charge of 0.9, were they usually intersect. It is evident that control of these pathways has evolved to maintain the energy charge within rather narrow limits. In other words the energy charge like the pH of a cell is buffered. The energy charge of most cells range from 0.8 to 0.95."
A high energy charge signals the slow down of metabolism.
A low energy charge signals up regulation of metabolism.
this text helps me for my class test thangs.