Carb Metabolism 2 Flashcards
RBCs rely exclusively on what for energy?
glycolysis because they DO NOT HAVE MITOCHONDRIA
All the steps of glycolysis :)
:)
What enzyme do we use to convert Glyceraldehyde 3 phosphate + NAD –> 1,3 bisphosphoglycerate?
glyceraldehyde phosphate dehydrogenase
What enzyme do we use yo convert 1,3 bisphosphoglycerate + ADP –> 3 phosphoglycerate
phosphoglycerate kinase
What are the 3 irreversible steps of glycolysis?
- Glucose + ATP –> hexokinase –> glu 6 phosphate
- Fruc 6 P + ATP –> PFK 1 –> Fruc 1,6 bisphosphate
- PEP + ADP –> pyruvate kinase–> pyruvate + ATP
Fructose can be used in two different ways (in 2 different areas..) explain
LIVER: Fructose –> fructokinase –> fructose 1 p
Fructose 1 p –> aldolase B –> Glyceraldehyde + DHAP (DHAP GOES TO GLYCOLYSIS)
MUSCLE: Fructose –> hexokinase –> fructose 6 P –> Glycolysis
Hexokinase is found where?
muscle
Fructokinase is found where?
liver
What does Galactose ultimately get broken down into?
Glucose 6 phosphate
How do we take UDP-glucose and get it to glucose 1 p? (1 step)
UDP-glucose –> Glu 1 P uridyltransferase–> glucose 1 p
What results from a deficiency of liver fructokinase?
essential fructosuria
Is essential fructosuria harmful?
no, fructose does not get converted to fruc 1 P and will be excreted in the urine
What is hereditary fructose intolerance?
aldolase B defiency, resulting in buildup of fruc 1 P; this can be bad for the liver
What happens if aldolase B is deficient?
hereditary fructose intolernance
How do you treat hereditary fructose intolerance?
fructose-free diet
What are 2 examples of inborn errors of metabolisim?
PKU
Galactosemia
What is galactosemia?
a failure to utilize galactose and can be caused by:
- a mutation in galactokinase
- galactose 1 phosphate uridyltransferase mutation
- UDP galactose epimerase mutation
How do you convert UDP-galactose –> UDP-glucose?
UDPG4-epimerase
What are the 3 regulated enzymes of glycolysis?
- hexokinase
- PFK-1
- pyruvate kinase
Hexokinase regulated by?
+ insulin
- gluc 6 P and acetyl-CoA
What is the rate limiting step of glycolysis?
PFK-1
PFK-1 regulation?
+hormones, ADP, AP
-ATP, citrate
Pyruvate kinase regulated by?
+fruc 1,6 bisphosphate, insulin
-ATP
A high cAMP concentration signals you are in what state?
fasting state; reducing glucose consumption by glycolysis
Draw the fruc 2,6 bisphosphate regulation.
:)
What 2 things activate PFK 2?
fruc 6 P
AMP
What activates cAMP? What inhibits?
+ glucagon
- insulin
PFK 2 is inhibited by what?
PKA
What are two shuttles used for NADH? include location
glycerol phosphate shuttle: muscle and brain
malate-aspartate shuttle: liver and heart
How much ATP do you get from the glycerol phosphate shuttle and from what agent?
you get 2 ATP from 1 FADH
What shuttle is located in the muscle and brain?
glycerol phosphate shuttle
How many ATP do you get from malate-aspartate shuttle and from what?
3 ATP from 1 NADH
What shuttle is located in the liver and heart?
malate-aspartate
Pyruvate gets ______ to lactic acid?
NADH gets ____ to NAD+?
pyruvate gets reduced
NADH gets oxidized
What 2 things produce lactate which must be converted back into glucose by the liver?
RBCS and muscles
Describe the CORI cycle.
- Pyruvate gets reduced to lactate in the RBCs/muscles
2. lactate is shuttled to the liver where it is oxidized to pyruvate and then synthesized into glucose
What is the most common hereditary enzymatic defect in glycolysis?
pyruvate kinase deficiency: lysis of RBCs
Arsenic poisoning?
arsenic mimics phosphate, so when gly 3 p is in the presence of arsenic, it forms a different product and no ATP is produced
