A "rák" nevű programhiba:
In many types of tumor cells, this interlocking
coordination appears to be defective: glycolysis proceeds
at a higher rate than required by the citric acid cycle.
As a result, cancer cells use far more blood glucose than
normal cells, but cannot oxidize the excess pyruvate
formed by rapid glycolysis, even in the presence of O2.
To reoxidize cytoplasmic NADH, most of the pyruvate is
reduced to lactate (Chapter 14), which passes from the
cells into the blood. The high glycolytic rate may result
in part from smaller numbers of mitochondria in tumor
cells. In addition, some tumor cells overproduce an
isozyme of hexokinase that associates with the cytosolic
face of the mitochondrial inner membrane and is
insensitive to feedback inhibition by glucose-6phosphate
(p. 432). This enzyme may monopolize the ATP produced in
mitochondria, using it to produce glucose-6-phosphate and
committing the cell to continue glycolysis.
Lehninger-Nelson-Cox: Principles of Biochemistry, 568.o.
homeostasis : The maintenance of a dynamic steady state by regulatory mechanisms that compensate for changes in external circumstances. ___...
A dalai láma felhívása a világhoz. Az etika fontosabb a vallásnál Ez nagy mondás. A láma urat is meg kell hívnunk a rendünkbe !
"Some proteins endow cells and organisms with the ability to contract, to change shape, or to move about. Actin and myosin function...
We begin in each case by considering the covalent structure of the simple subunits (amino acids, fatty acids, monosaccharides, and nucleoti...