Gluconeogenesis

Question 1

define gluconeogenesis

Answer 1

forming glucose from non carb precursors (pyruvate, lactate, glycerol, amino acids)

Question 2

where does gluconeogenesis occur?

Answer 2

cytosol, liver (also renal cortex to a lesser extent)

Question 3

describe energy obtained from diet, glycogen and gluconeogenesis when starving

Answer 3

first four hours: mainly diet, strong decline.
4 hrs - 2 days: glycogen
from about 4 hours on: gluconeogenesis, very slow but steady rise.

Question 4

describe energy obtained from diet, glycogen and gluconeogenesis between meals

Answer 4

spike for diet immediately after meals
in between meals, lesser spike for glycogenolysis and smallest for gluconeogenesis.
biggest proportion of gluconeogenesis in the night

Question 5

describe bypass one

Answer 5

pyruvate(cyt)–>pyruvate(matrix)–pyruvate carboxylase–>oxaloacetate–>malate(matrix)–malate shuttle–>malate(cytosol)–>oxaloacetate–PEP carboxylase–>phosphoenol pyruvate

ENZYMES/COFACTORS INFERRED FROM CAC

Question 6

describe bypass 2

Answer 6

fructose-1,6-biphosphate+H2O–fructose-1,6-biphosphatase–> fructose-6-phosphate + Pi

Question 7

describe bypass 3

Answer 7

glucose-6-phosphate + H2O –glucose-6-phosphatase–>glucose + Pi

Question 8

overall, glycolysis _________ energy while gluconeogenesis _________ energy.

Answer 8

produces

consumes

Question 9

how does lactate enter GNG

Answer 9

lactate + NAD+—> pyruvate (cytosol) + NADH + H+ —->pyruvate +Co2 (matrix) –> oxaloacetate —> PEP(matrix) +Co2 —> PEP (cytosol) —> GNG

Question 10

describe cori cycle

Answer 10

in muscle, glycogen is converted to lactate, producing ATP.
lactate crosses blood to liver.
in liver, lactate undergoes GNG to become glucose.
glucose crosses through blood to muscle where its converted to glycogen.

Question 11

describe amino acid cycle

Answer 11

glucose coverted to pyruvate in muscles via glycolysis
pyruvate gets converted to alanine.
alanine crosses blood to liver where it is converted to pyruvate agian.
in liver pyruvate is converted to glucose via GNG.
glucose crosses via blood to muscle. cycle continues

Question 12

how is pyruvate converted to alanine.

Answer 12

muscle protein –> aa –> NH4+ –>glutamate

pyruvate + glutamate –alanine aminotransferase–> alanine + alpha ketoglutarate

Question 13

how is alanine converted to pyruvate

Answer 13

alanine + alpha ketoglutarate –alanine aminotransferase–> glutamate + pyruvate