Energy Reactions In Cells Flashcards
What are the high energy signals within a cell?
ATP, NADH, NADPH, FAD2H
What are the low energy signals within a cell?
ADP, AMP, NADP+, NAD+, FAD
What is the role of creatine phosphate within the cell?
When there is high atp in the cell, it is used to drive the reaction of creatinine to form creatine phosphate. This can act as a small store of energy for the cell, used in the first few minutes of exercise.
What are the two enzymes involved in the metabolism of galactose?
Galactokinase (1st step to galactose 1-P) and galactose 1-P uridyl transferase .
What is the importance of UDP galactose 4 epimerase?
It catalyses a reversible reaction from UDP glucose to UDP galactose, and so can allow galactose to be produced from glucose in the production of breast milk.
What is the most common cause of galactosemia?
Deficiency of the glucose 1P uridyl transferase enzyme.
What are the biochemical consequences of galactosemia?
Galactose and galactose 1P acculmate, which can damage the liver, kidney and brain. This can raise the intraocular pressure, causing glaucoma and potential blindness, as well as non-emzymatic glycoslation of lens proteins which can contribute to the formation of cataracts. Also, galactose is reduced to galictol by aldose reductase, oxidising NADPH. This reduces the amount of NADPH available to tissues, and has consequences such as inapproiate disulphide bond formation.
What is the pentose phosphate pathway?
It is a process that uses glucose 6 phosphate to produce NADPH and 5 carbon sugars (eg riboses)
What does phase 1 of the pentose phosphate pathway do?
Glucose 6 phosphate is oxidised using glucose 6 phosphate dehydrogenase, and decarboxykate using 6- phosphoglucumate dehyrdogenase in a process that requires NADP+, producing NADPH and a five carbon sugar.
What does phase 2 of the pentose phosphate pathway do?
Converts unused 5 carbon sugars back to one of the intermediates of glycolysis.
What is the key control enzyme of the pentose phosphate pathway?
Glucose 6 phosphate dehydrogenase.
What are the consequences of glucose 6 phosphate dehydrogenase defienency?
NADPH is needed to recycle gluthaione back to its reductive form, and with a deficient of NADPH it can not be recycled back to prevent oxidative damage. This particularly effects red blood cells, where the pentose phosphate pathway is the only source of NADPH, where hameoglobin is cross linked by disulphide bonds, leading to heinz bodies and haemolysis .
What can cause acute haemolytic episodes in individuals with G6PD deficiency?
Antimalarials, sulphonamides and glycosides which are found in broad beans.
What is pyruvate converted too?
Acteyl CoA by pyruvate dehydrogenase.
