MISC Pathways 3 Flashcards
GLUT 2 + GLUT 4 found where?
GLUT 2: liver, brain
- insulin indep
- constant
GLUT4: muscle
- insul sens. meaning more glucose will transport into the cell following insulin exposure
What is the RLS in glycolysis?
F6P –> F1,6 BP
What does phosphorylation of Glucose to G6P accomplish?
- P gives intermediates a net NEGATIVE charge - preventing diffusion out of the cell.
- glucose is trapped - Phosphorylation conserves metabolic energy
- P lowers activation E and increases the specificity of the enzymatic rxn
1st substrate level phosphorylation in glycolysis is what step?
1,3 BPG –> 3 phosphoglycerate
2nd one is PEP –> pyruvate
In liver and heart what is the NADH/NAD ratio? Why is this important when it comes to regulating the circulatory sys?
The ratio of NADH/NAD is lower than in exercising muscle. This means that they convert lactate to pyruvate.
-Lactic acidosis results when there is an elevated level of lactate in plasma due to collapse of the circulatory sys.
(MI, Ischemic bowel, PE)
In which step of the TCA cycle is CO2 and NADH produced?
Isocitrate –> a-ketoglutarate
and also
a-ketoglutarate –> succinyl coA
Only substrate level P in the TCA
Succinyl coA –> succinate
GTP can be converted to ATP
entrance points for aa in the TCA
a-ketoglutarate
succinyl coa
fumarate
Key mediator of mitochondrial proliferation
PGC1-a
- critical for health outcomes
what two aa are most important to serve as carbon skeletons for the gluconeogenic pathway during protein breakdown
alanine and glutamine
is there a net conversion of FA to glucose?
NO! The 2 Cs that enter the TCA cycle as acetyl CoA (from beta oxidation)leave the TCA as CO2, leaving NO carbons to contribute to glucose synthesis.
- but FA DO provide E for gluconeogenesis via oxidation
Biotin is an imp cofactor for which enzyme?
Pyruvate carboxylase
(binds biotin and moves CO2 remember?) to convert pyruvate –> oxalo
biotin def leads to lactic acidosis via build up of pyruvate
Malate dehydrogenase (mitochondrial vs cytosolic)
Mitochondrial malate dehydrogenase:
catalyzes Malate –> OAA
Cytosolic malate dehydrogenase:
OAA –> PEP
Von Gierkes disease
AR deficiency of G6-phosphatase in liver
–>
Cant convert G6P to glucose –>
indiv have severe fasting hypoglycemia,
ketosis,
lactic acidosis
enlarged liver and kisneys
Depending on prior nutrition, liver glycogen can be depleted in as little as ____ hours
12-24 hours. Glycogen can serve as a buffer to maintain blood glucose levels but only within 1 day of a fast.
