The Liver & Gluconeogenesis Flashcards
What is a normal blood glucose level?
3.9 - 6.7 mM
Normal fasting = 4.5 - 5.0 mM
What are the X4 processes that occur in catabolic pathways to add oxygen to a molecule?
(TCA cycle and b-oxidation pathway)
In synthetic reactions how does this differ?
Dehydrogenase, hydrate then dehydrogenate.
In synthetic reactions, we do the reverse process.
What is glucose also a source of, and what is the name of the pathway for synthesising these molecules for further synthetic reactions of DNA and nucleotides?
Glucose = a source of pentode sugars
Pathway = pie rose phosphate shunt
What cofactor is needed for synthetic reactions?
NADPH.
Why is glycogen favoured as a storage molecule over glucose?
Glucose is osmotically active.
What is the name of the blood test which can measure glycosylated Hb?
HBA1C
Where does the glycerol-3-phosphate needed to form triglycerides come from in the:
1) Liver
2) Adipose tissue
1) Directly from glycerol via the enzyme glycerol kinase.
2) from glycolysis of glucose, as the adipocytes do not have the glycerol kinase enzyme. The immediate precursor in this case is therefore dihydroxyacetone phosphate.
Where does gluconeogenesis occur?
In the liver.
Which X3 reactions (irreversible in glycolysis) must be bypassed within gluconeogenesis in order to synthesise glucose?
1) glucose —> glucose-6-phosphate (hexokinase/glucokinase)
2) fructose-6-phosphate —> fructose 1,6-bisphosphate (phosphofructokinase)
3) phosphoenol pyruvate —> pyruvate (pyruvate kinase)
Which enzyme is required to bypass in the reverse direction the reaction:
1) glucose —> glucose-6-phosphate (hexokinase/glucokinase)
…which is the final step of gluconeogenesis?
Glucose-6-phosphatase.
Requires H2O and produces a Pi.
Which enzyme is required to bypass in the reverse direction the reaction:
2) fructose-6-phosphate —> fructose 1,6-bisphosphate
Fructose 1,6-bisphosphatase.
Requires H2O and Pi is produced.
Which X2 enzymes are required to bypass in the reverse direction the reaction:
3) phosphoenol pyruvate —> pyruvate kinase
This bypass is in X2 stages:
1) pyruvate —> oxaloacetate
= via the enzyme pyruvate carboxylase
= requires X2 CO2, X2 ATP & X2 H2O
2) oxaloacetate —> phosphoenolpyruvate
= via the enzyme PEP carboxylase
= requires X2 GTP
What do the cori-cycle and the glucose-alanine cycle do?
Which cycle deals with which molecule?
They transport waste products from the skeletal muscle cells to the liver to synthesis glucose.
Cori cycle = lactate
Glucose alanine cycle = alanine
Which pancreatic cells in the islets of Langerhans secrete glucagon?
Alpha-cells!
