Biochemistry- Flashcards
Gluconeogenesis takes ___ and turns it into ___
Pyruvate, glucose
Where can carbons come from (for glucose synthesis)?
Pyruvate, Lactate, Amino Acids, Propionate, Glycerol (PLAPG)
What is propionate and what does it have to do with glucose?
Propionate is an odd number chain fats and it can be a source of glucose
What is pyruvate?
It is an end product of glycolysis
How can pyruvate molecules be used by the skeletal muscle?
It can be converted into alanine and this alanine can later travel to liver and converted into glucose
What is the relationship between pyruvate and the cori cycle
The cori cycle is when pyruvate -> lactate (via anaerobic metabolism) in skeletal muscles and RBCs —> secreted into the plasma and reaches the liver to be converted into glucose
What is the fate of the pyruvate that can yield most energy (ATP)?
By converting it into acetyl-COA and sending it to the TCA cycle.
What are the potential pathways pyruvate can take?
Alanine (skeletal muscle-> liver in glucose), acetyl coa and TCA cycle, lactate (skeletal muscle, RBC) then liver glucose, and BACK to glucose by gluconeogenesis.
How does the cell decide between going into acetyl-coa vs gluconeogenesis from pyruvate?
It uses acetyl coa as an indicator of the metabolic activity of the cell
What happens to the metabolism of a cell if there is a lot of ATPs present?
ATP is is an inhibitor of many of the enzymes in the TCA cycle. This means that the ATPs that are created from the TCA cycle stops the TCA cycle and acetyl coa level rises.
Then, acetyl Coa is an important allosteric activator of pyruvate carboxylase
What does the pyruvate carboxylase to in gluconeogenesis?
It helps get around the irreversible step from glycolysis so that it can go back to phosphoenolpyruvate. How does it do that? It take a roundabout way to reach oxaloacetate, by taking carbon from CO2 and use ATP to add COOH (carboxylic acid group) to pyruvate
What are the symptoms have pyruvate carboxylase deficiency?
They mostly show failure to thrive. They can have elevated alanine/ elevated pyruvate into lactate (which would lead to lactic acidosis)
One unique step in which both enzymes (and their relative activity) contributes to determining whether it proceeds to glycolysis or gluconeogenesis
Between Fructose-6-phosphate to F1,6BP (PFK-1 and F1,6 bisphosphatase1) .
The activities of the two enzymes are regulated by the availability of ATP and AMP/ F2,6BP
What is the molecule that the hormone insulin and glucagon use to regulate the direction?
Fructose 2,6, BP Is an on/off switch for glycolysis: when F26BP is high gly is on. (Low, off)
How is acetyl coa important in gluconeogenesis?
It’s very important in the step of turning pyruvate into phosphoenolpyruvate because it is an allosteric activator of pyruvate carboxylase (adding CCOH to yield oxaloacetate)
