Glycolysis Flashcards
how is insulin release biphasic
1 preformed : within 15 min
2 gene level
name irreversible steps in glycolysis
- hexo/glucokinase
- phosphofructokinase 1
- pyruvate kinase
what fxn as glucose sensor in b cell of pancreas
glucokinase
glut 2
where is glucokinase found. comment on its Km
hepatocytes and b cell of pancreas
higher than hexokinase
effect of arsenate on glycolysis
forms 1arseno3phosphoglycerate which undergo hydolysis preventing atp formation
rate limiting and main control point in glycolysis
PK1
control of Pk1 by insulin and glucagon is indirect via PK2. True/false
true via 2,3 bisphosphoglycerate
mcc genetic cause of hemolytic anemia
G6PD def
2nd:pyruvate kinase def
diff G6PD and PK def
abscence of heinz bodies
inc 2,3-BPG
why aldose B def is severe
because it leads to accumulation of F1P in proximal renal tubules and liver
fructokinasecdef is benign
why no cataract formation in fructosemia
beacause fructose is a ketose
not met by aldose reductase in lens
def of gal 1 p tranferase is more sever2 tjan galactokinase
same reason
diagnosis of lactose intolerance based on
positive H2 breath test
bact breaks lactose to CH4 H2 and osmotically active organic acids
can milk product yoghurt be taken by LI person
yes, unpasteurised because it has lactobacillus to digest lactose
why a high fructose drink supplies quick energy then glucose
fructose 1 p products DHAP and G3P are downstream of the key reg of pathway PK1
it is not so with galactose it gets converted to glucose
can AcetyCoA be converted back to glucose
no
PD is an irreversible enzyme
why thiamine given along with glucose in emergency
to prevent lactic acidosis when glycose/dextrose is given
thiamine lipoic acid CoA FAD NAD
PD
a ketoglutarate dehydrogenase
branched chain ketoacid dehydrogenase
gycogen synthesis inhibited by
m:epinephrine
liver:epi+glucagon
via inhibition of glucagon phosphorylase
and stimaltion of synthase via insulin
how is free glucose produced during glycogenolysis
as a result of debranching enzyme
1.breaks a1.4 bond and attach this oligoglucose to the exposed end of other chain to form new a 1.4 bond
2.hydrolyse the single a1.6 bond releasing the single residue as free glucose
since it is not a phosphorylase so no Pi is added to it
von gierke:severe hypoglycemia
hers:mild
how?
in von gierke glucose cant come from either glycogenolysis or gluconeogenesis
cardiomegaly in
pompe
branching and debranching enz defect
anderson
cori
features of von gierke
- glcogen deposits in liver:G6P inhibits lysis and promotes glycogen syn
- hyperuricemia:dec Pi and inc AMP
- hyperlipidemia and skin xanthoma
- fatty liver
