E2 Gluconeogenesis (Bobby) Flashcards

(77 cards)

1
Q

T/F. GNG synthesizes glucose from carbohydrate precursors.

A

False; non-carbohydrate precursors

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2
Q

In order from most to least, which tissues perform GNG?

A
  1. Liver (90%) 2. Kidney (40%) 3. SI (minimal)
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3
Q

During fasting, which tissue performs GNG?

A

Kidney

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4
Q

What is the purpose of GNG?

A

Maintain blood glucose concentration

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5
Q

During which 3 states will GNG be required and what is used to make glucose in each?

A
  1. Starving- aa
  2. Fasting or low carbohydrate- aa
  3. Exercise- lactic acid and alanine
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6
Q

Which produces glucose faster, glycolysis or GNG?

A

Glycolysis

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7
Q

How much glucose can we store?

A

Enough for 1 day

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8
Q

Which hormone will stimulate GNG? Inhibit GNG?

A

Stimulate- Glucagon

Inhibit- Insulin

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9
Q

Matching.
1. Glycerol 2. Lactic Acid 3. Amino Acids

A. Produced during anaerobic glycolysis
B. TG backbone
C. Convert into pyruvate and OAA

A
  1. B
  2. A
  3. C
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10
Q

What tissue does glycerol come from?

A

Adipose

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11
Q

Glycerol is produced from TG’s by what process?

A

Hydrolysis

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12
Q

T/F. Glycerol is a major source of making glucose via GNG.

A

False

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13
Q

What are the 3 substrates of GNG?

A

Glycerol
Lactic Acid
Amino Acids

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14
Q

What enzyme converts glycerol —> glycerol phosphate?

A

Glycerol Kinase

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15
Q

T/F. GNG uses coupled rxn’s due to energy requirement.

A

True

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16
Q

What enzyme converts glycerol phosphate —> DHAP?

A

G-3-P DH

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17
Q

Once DHAP is produced, it can enter:

A. GNG
B. Glycolysis
C. Both

A

C. Both

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18
Q

Cells without mitochondria release which substrate?

A

Lactic Acid

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19
Q

T/F. Muscle release lactate via aerobic glycolysis.

A

False; anaerobic glycolysis

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20
Q

How are glucose and lactate exchanged between muscle and the liver?

A

Via Blood

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21
Q

Which enzyme facilitates pyruvate —> lactate?

A

Lactate DH

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22
Q

What condition would stimulate conversation of amino acids to glucose?

A

Starvation and low carbohydrates

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23
Q

Before becoming glucose, amino acids are turned into ________ (carbon skeleton).

A

Alpha ketoacid (pyruvate)

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24
Q

Which 2 amino acids are non-glucogenic and thus cannot be used as substrates for GNG?

A

Leucine and Lysine

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25
What is the fate of an amino group after amino acid catabolism?
Use or Secrete it
26
What is the primary source of glucose for GNG at rest and during fasting?
Amino Acids
27
In which tissue does lactate ---> pyruvate via lactate DH occur?
Liver
28
What are the 3 fates of alpha ketoacid?
1. Energy 2. Glucose 3. Fatty Acid
29
What 4 factors direct breakdown of amino acids?
1. High energy charge 2. Hormones (glucagon) 3. Low glucose concentration 4. Tissue (liver vs. muscle)
30
What is the coenzyme of pyruvate carboxylase?
Biotin
31
What regulates pyruvate carboxylase?
Acetyl CoA
32
What enzyme facilitates alanine ---> pyruvate?
ALT (alanine aminotransferase)
33
How many irreversible rxn's are in glycolysis? GNG?
Glycolysis- 3 | GNG- 4
34
Which irreversible GNG rxn requires ATP? GTP?
``` ATP= pyruvate ---> OAA GTP= OAA ---> PEP ```
35
Which GNG enzymes require Mg2+?
PEP carboxykinase F-1-6 bisphosphatase G-6- phosphatase
36
Pyruvate carboxylase is found in the mitochondria of which 2 tissues?
Liver and Kidney
37
T/F. Pyruvate carboxylase is not found in muscle and the brain.
False; it is found there but does not synthesize glucose
38
What is the location of the 1st half of the 1st obstacle of GNG?
Matrix
39
What effect does acetyl CoA have on pyruvate carboxylase?
Stimulate
40
What is the location of the 2nd half of the 1st obstacle of GNG?
Cytosol (pyruvate/ALA) or Matrix (lactate)
41
What enzyme facilitates OAA ---> PEP?
PEP carboxykinase
42
Which specific obstacle requires ATP? GTP?
ATP- 1st half of 1 | GTP- 2nd half of 1
43
What are the precursors for PEP carboxykinase?
Pyruvate, alanine, lactate
44
Which precursor(s) require a malate shuttle?
Pyruvate and Alanine
45
What structure does the malate shuttle transport?
OAA
46
What is location for the precursors for PEP carboxykinase? 1. Pyruvate 2. Lactate 3. Alanine A. Cytosol B. Matrix
1. A 2. B 3. A
47
What enzyme facilitates OAA malate?
Malate DH
48
What is the location of lactate DH?
Cytosol
49
What is the key regulatory step in GNG?
F-1-6 bisphosphatase
50
What is the key regulatory step in glycolysis?
PFK
51
What enzyme facilitates F-6-P ---> F-1,6-bisphosphate?
PFK
52
What inhibits the 2nd obstacle of GNG?
1. Low energy | 2. High F-6-P
53
What enzyme facilitates F-1,6-bisphosphate ---> F-6-P?
F-1,6-bisphosphatase
54
Where does the 2nd obstacle take place?
Cytosol
55
What enzyme facilitates glucose ---> G-6-P in the muscle?
Hexokinase
56
What enzyme facilitates G-6-P ---> glucose?
G-6-phosphatase
57
What enzyme facilitates glucose ---> G-6-P in the liver?
Glucokinase
58
What is the location of the 3rd obstacle of GNG?
Endoplasmic reticulum (rxn)
59
Where is glucose from the 3rd obstacle sent?
Cytosol
60
T/F. Muscle does have G-6-phosphatase?
False
61
T/F. In muscle, glucose is trapped when phosphorylated.
True
62
T/F. Glycogen in muscle will be released as glucose.
False
63
What two tissues release glucose, this maintaining glucose homeostasis?
Liver and Kidney
64
How many pyruvates are used in GNG per 1 glucose made?
2
65
How many total phosphate groups are produced via GNG per 1 glucose made?
6
66
How many ATP, GTP, and NADH are used in GNG per 1 glucose produced?
4 ATP, 2 GTP, 2 NADH
67
What secretes insulin?
Beta cells from the pancreas
68
What effect does insulin have on GNG?
Inhibit
69
What secretes glucagon?
Alpha cells in pancreas
70
What effect does glucagon have on GNG?
Stimulate
71
What effect does high AMP have on PFK?
Stimulate
72
What effect does high ATP have on F-1,6-bisphosphate?
Stimulate
73
What effect does high citrate have on PFK?
Inhibit
74
What effect does high ADP have on pyruvate carboxylase and PEP carboxykinase?
Inhibit
75
What effect does high F-2,6-bisphosphate have on F-1,6-bisphophatase?
Inhibit
76
What effect does low blood glucose concentration have on GNG? CAMP cascade?
GNG- stimulate | CAMP- stimulate
77
What effect does high citrate concentration have on GNG?
Stimulate