WK1_1 Gluconeogenesis

Question 1

A patient presented with a bacterial infection that produced an endotoxin that inhibits phosphoenolpyruvate carboxykinase. In this patient, then under theses conditions, glucose production from which of the following precursors would be inhibited?

Answer 1

alanine

Question 2

a common intermediate in the conversion of glycerol and lactate to glucose is which of the following?

Answer 2

glucose-6-phosphate

Question 3

gluconeogenesis

Answer 3

synthesis of glucose from non-sugar precursors, including lactate, glycerol and glycogenic aa’s

Question 4

where does gluconeogeneis take place?

Answer 4

in the liver (primary site) & kidneys (lesser extent)

Question 5

gluconeogenesis helps maintain the homeostasis of _____ during _____ and _____ which in turn provides a constant supply of glucose for oxidation by RBCs and the brain.

Answer 5

blood glucose levels; fasting; starvation

Question 6

during fasting, blood glucose is generated by _____ in the liver, and to a lesser extent by _____.

Answer 6

glycogenolysis; gluconeogenesis

Question 7

during starvation, liver glycogen stores are depleted and _____ is the only pathway for glucose production

Answer 7

gluconeogenesis

Question 8

T/F gluconeogenesis is a reversal of glycolysis

Answer 8

FALSE. gluconeogenesis is NOT a reversal of glycolysis

Question 9

do gluconeogenesis and glycolysis have independent or dependent regulation?

Answer 9

independent

Question 10

T/F gluconeogenesis and glycolysis are competing pathways.

Answer 10

TRUE

Question 11

why are gluconeogenesis and glycolysis competing pathways?

Answer 11

since the product of gluconeogenesis (glucose) is the substrate for glycolysis

Question 12

gluconeogenesis is stimulated by _____ and inhibited by _____

Answer 12

glucagon; insulin

Question 13

in the liver, gluconeogenesis and glycolysis are _____ regulated by insulin and glucagon in order to prevent futile cycling of glucose.

Answer 13

reciprocally

Question 14

reciprocal regulation of gluconeogenesis and glycolysis:

1) ?
2) ?

Answer 14

1) prevents the oxidation of glucose generated by gluconeogenesis
2) allows the newly synthesized glucose to be deposited into the circulation

Question 15

insulin and glucagon reciprocally regulate glycogenesis and glycogenolysis in the liver, which prevents:

Answer 15

futile cycling of the glucose produced by glycogenolysis by preventing its incorporation into glycogen

Question 16

when does gluconeogenesis occur?

Answer 16

during the fasting state and starvation

Question 17

where (organelle) does gluconeogenesis start?

Answer 17

mitochondria

Question 18

where does gluconeogenesis go from mitochondria?

Answer 18

cytoplasm

Question 19

where can you find glycerol kinase?

Answer 19

only in the liver

Question 20

what are the 3 ways that glycogenic amino acids enter gluconeogenesis?

Answer 20

1) by conversion to pyruvate which then enters gluconeogenesis
OR
2) conversion to intermediates fo the TCA cycle which are then converted to oxaloacetate which enters gluconeogenesis
OR
3) by conversion to oxaloacetate which enters gluconeogenesis

Question 21

how much % of the glucose produced by gluconeogenesis is derived by glycogenic amino acids produced by the degradation of muscle proteins?

Answer 21

60%

Question 22

how much % of the glucose produced by gluconeogenesis is derived by lactate via the Cori cycle?

Answer 22

28%

Question 23

how much % of the glucose produced by gluconeogenesis is derived by glycerol produced by lipolysis in adipose tissue?

Answer 23

12%