FA/amboss glycolysis and genesis regulation 12/22

Question 1

Glycolysis rate determining enzyme?

Answer 1

Phosphofructokinase-1 (PFK-1)

Question 2

Phosphofructokinase-1 (PFK-1) enzyme in what process?

Answer 2

Glycolysis

Question 3

what 2 enzymes use ATP?

Answer 3

hexokinase/glucokinase;
PFK-1

Question 4

what 1 enzymes produce NADH?

Answer 4

glyceraldehyde-3P dehydrogenase

Question 5

what 2 enzymes produce ATP?

Answer 5

Phosphoglycerate kinase;
Pyruvate kinase

Question 6

what inhibits hexokinase?

Answer 6

G6P (feedback inhibition)

Question 7

what inhibits glucokinase?

Answer 7

Fructose 6-phosphate (feedback inhibition);
glucagon

Question 8

what stimulates hexokinase?

Answer 8

nothing

Question 9

what stimulates glucokinase?

Answer 9

insulin (Upregulates transcription of glucokinase gene)

Question 10

what stimulates PFK-1?

Answer 10

AMP;
Fructose 2,6-bisphosphate;
Insulin (postprandial): indirect stimulation

Question 11

What inhibits PFK-1?

Answer 11

ATP
Citrate
Low pH
Glucagon (fasting, only in the liver): indirect inhibition

Question 12

what stimulates pyruvate kinase?

Answer 12

Fructose 1,6-bisphosphate (feed-forward stimulation)
The higher its concentration, the greater the activity of pyruvate kinase.

Question 13

what inhibits pyruvate kinase?

Answer 13

ATP;
alanine (indicates a sufficient amount of precursors for biosynthesis)

Question 14

glycolysis location?

Answer 14

cytosol

Question 15

gluconeogenesis location?

Answer 15

mitochondria and cytosol

Question 16

gluconeogenesis rate limiting?

Answer 16

Fructose 1,6-bisphosphatase

Question 17

what activates gluconeogenesis?

Answer 17

Glucagon

Question 18

what inhibits gluconeogenesis?

Answer 18

Insulin

Question 19

when occurs gluconeogenesis?

Answer 19

Fasting state

Question 20

when occurs glycolysis?

Answer 20

Stimulated in postprandial state
Occurs independent of postprandial state in some cells (e.g., RBCs)

Question 21

in glycolysis how many ATP are invested, how many produced, what is net ATP per 1 glucose molecule?

Answer 21

In glycolysis, 2 ATP are invested to gain 4 ATP. In total, there is a net gain of 2 ATP per 1 molecule of glucose.

Question 22

what molecule participated in feed-forward regulation (indirect cia bus)?

Answer 22

Fructose 2,6-bisphosphate (feed-forward regulation)

Question 23

function of Fructose 2,6-bisphosphate (Fru-2,6-P2)?

Answer 23

Fructose 2,6-bisphosphate (Fru-2,6-P2) stimulates glycolysis by increasing PFK-1 activity in states of high blood glucose concentrations.

Question 24

What 2 enzymes are in two domains of the same bifunctional enzyme?

Answer 24

Phosphofructokinase-2 (PFK-2) and fructose bisphosphatase-2 (FBPase-2).

Question 25

what substance reverse bifunctional enzyme?

Answer 25

function is reversed by phosphorylation by protein kinase A.

Question 26

PKA. In dephosphorylated state what enzyme?

Answer 26

Dephosphorylated state: ↑ PFK-2 activity results in ↑ fructose 2,6-bisphosphate (conversion of fructose 6-phosphate to fructose 2,6-bisphosphate).

Question 27

PKA. In phosphorylated state what enzyme?

Answer 27

Phosphorylated state: ↑ FBPase-2 activity results in ↓ fructose 2,6-bisphosphate (conversion of fructose 2,6-bisphosphate to fructose 6-phosphate).

Question 28

in fed state?

Answer 28

fructose-6-P --> fructose2,6-BP Enzyme: phosphofructokinase-2 (PFK-2)

Question 29

in fasting state?

Answer 29

fructose2,6-BP --> fructose-6-P --> gluconeogenesis enzyme: fructose bisphosphatase-2 (FBPase-2)

Question 30

in liver fasting state?

Answer 30

Fasting state: ↓ blood glucose → ↑ glucagon → ↑ cAMP → ↑ protein kinase A activity → ↑ phosphorylation of PFK-2/FBPase-2 → ↑ FBPase-2 activity and ↓ PFK-2 activity → ↓ Fru-2,6-P2 → ↓ PFK-1 activity → ↑ gluconeogenesis and ↓ glycolysis

Question 31

in liver fed state?

Answer 31

Postprandial state: ↑ blood glucose → ↑ insulin → ↓ cAMP → ↓ protein kinase A activity → ↓ phosphorylation of PFK-2/FBPase-2 → ↑ PFK-2 activity and ↓ FBPase-2 → ↑ Fru-2,6-P2 → ↑ PFK-1 activity → ↑ glycolysis and ↓ gluconeogenesis

Question 32

in heart glycolysis?

Answer 32

In the heart: epinephrine and/or insulin → ↑ PFK-2 activity → ↑ Fru-2,6-P2 → ↑ PFK-1 activity → ↑ glycolysis provides quick energy, e.g., during stress or physical activity

Question 33

gluconeogenesis rate limiting enzyme?

Answer 33

fructose-1,6-bisphosphatase

Question 34

what activates fructose-1,6-bisphosphatase? gluconeogenesis

Answer 34

citrate

Question 35

what inhibits fructose-1,6-bisphosphatase?

Answer 35

AMP, fructose 2,6- bisphosphate

Question 36

enzymes in gluconeogenesis?

Answer 36

Pyruvate carboxylase Phosphoenolpyruvate carboxykinase Fructose 1,6-bisphosphatase Glucose-6-phosphatase

Question 37

what activates Pyruvate carboxylase?

Answer 37

acetyl-coa; Glucagon in fasting state

Question 38

what inhibits pyruvate carboxylase?

Answer 38

ADP

Question 39

what requires phosphoenolpyruvate carboxykinase?gluconeogenesis

Answer 39

GTP

Question 40

what stimulates phosphoenolpyruvate carboxykinase?

Answer 40

Glucagon: activates adenylate cyclase → ↑ cAMP → activates CREB → ↑ transcription of PEP carboxykinase Cortisol: upregulates transcription Glucagon in fasting state

Question 41

what inhibits phosphoenolpyruvate carboxykinase?

Answer 41

Insulin

Question 42

what is rate limiting in glucoenogenesis?

Answer 42

Fructose 1,6-bisphosphatase

Question 43

what activates fructose 1,6-bisphosphatase?(gluconeogenesis)

Answer 43

Citrate ATP Fructose 1,6-bisphosphate (feed-forward regulation) Glucagon in fasting state

Question 44

what inhibits fructose 1,6-bisphosphatase?

Answer 44

Fructose 2,6-bisphosphate AMP

Question 45

what stimulates Glucose-6-phosphatase?

Answer 45

G6P (feed-forward regulation) Glucagon in fasting state

Question 46

what inhibits Glucose-6-phosphatase?

Answer 46

Insulin

Question 47

Gluconeogenesis is activated when energy is required (i.e., ....... ratio)

Answer 47

Gluconeogenesis is activated when energy is required (i.e., low ATP/AMP ratio)

Question 48

Gluconeogenesis is inhibited if there is an excess of energy available (i.e., ...... ratio).

Answer 48

Gluconeogenesis is inhibited if there is an excess of energy available (i.e., large ATP/AMP ratio).

Question 49

Pyruvate carboxylase location?

Answer 49

Mitochondria

Question 50

Phosphoenolpyruvate carboxykinase location?

Answer 50

Cytosol and mitochondria

Question 51

Fructose 1,6-bisphosphatase location?

Answer 51

Cytosol

Question 52

Glucose-6-phosphatase location?(gluconeogenesis)

Answer 52

Endoplasmic reticulum (to export glucose to blood serum)