Gluconeogenesis

Question 1

Pyruvate carboxylase

Answer 1

Mitochondrial

Bicarb + pyruvate=oxaloacetate

• uses ATP
• needs biotin (inhib by avidin-raw egg)
• Obligate activator-acetyl COA

aka ABC carboxylase
-C is CO2

Question 2

Phosphoenol carboxylase

Answer 2

PEPCK-both mito and cyto

oxaloacetate+GTP=Phsphoenolpyruvate+CO2+GDP

precursors

• pyruvate/alanine to malate to oxaloacetate
  - malate shuttle=makes NAD+
  - into cyto as malate-make NADH-then oxalo then PEP
• Lactate-made NADH-into mito and becomes PEP in mito

Question 3

Fructose 1,6 bisphosphatase

Answer 3

FBP1

cytoplasmic

fructose 1,6 bisphosphate to fructose 6 P
-changes to glucose 6P right after if gradient favors

hormonally and allosterically regulated
-AMP and fructose 2,6 bisphophosphate are inhibitors

Question 4

Glucose 6 phosphatase

Answer 4

ER bound
-ONLY IN LIVER

glucose 6 P to glucose
-glucose can leave via GLUT2

Question 5

5 reversible reactions occur when and what make/consumed

Answer 5

after making PEP to making fructose 1,6 bisphosphate

-ATP/NADH are used up

Question 6

FBP1 def

Answer 6

lactic acidosis (no clearance by gluconeogenesis)

can’t regulate glucose levels=hypoglycemia
-impair formation of glucose from all gluconeogenic precursors

can get normoglycemia if get enough glucose in, and enough degradation of hepatic glycogen

frequent feeding with carbs=TRX

freq of attacks decrease with age-most children have normal psychomotor dev

Question 7

AA in gluconeogenesis

Answer 7

Leu and Lys are only ketogenic-breakdown limited to acetyl CoA

Tyr is gluco and keto genic

Isoleucine, phenylalanine, and Tryptophan are also gluco and ketogogenic

glucogenic=donate carbon skeleton to somewhere in TCA

Question 8

Cori cycle

Answer 8

liver uptakes lactate and makes glucose

Muscle uptakes glucose and glycolysis to lactate @rapid contraction (or normal)

pyruvate is middle step between two

Question 9

Cahill Cycle

Answer 9

Alanine from active muscle or @fast is converted to glucose in liver

• alanine from skeletal muscle breaking down for energy-also ammonia made
• —can also get AA from diet
• —or from lactate(?)

glucose lyse to pyruvate to get alanine
alanine to pyruvate to glucose

Question 10

Hyperglycemic mom and fat baby that passes out

Answer 10

Mom gives tons of glucose to baby, baby makes tons of insulin

• baby insulin makes all glucose take up-make glycogen
• baby has low blood sugar

Question 11

AA in starving vs fed

Answer 11

AA from muscle breakdown

• gluconeogenesis
• glucose to TAGS to acetyl COA to ketones
• NO TCA!!!!

AA from diet

• TCA cycle running (Most important)
• acetyl COA to TAGs to glucose to glycolysis to acetyl COA