Gluconeogensis

Question 1

what is gluconeogenesis

Answer 1

making new glucose from non-carbohydrates (occurs mainly in the liver)

Question 2

Glucose can be metabolised to pyruvate to acetyl CoA, which can be used in:

Answer 2

• Amino acid synthesis
• Fatty acid synthesis –> Stored at triacylglycerol
• The citric acid cycle

Question 3

Glucose can also be used to make

Answer 3

ribose 5 phosphate

Question 4

First bypass step

Answer 4

pyruvate to phophoenolpyruvate (PEP)

Question 5

1st bypass steps

Answer 5

• pyruvate enters mitochondria
• uses ATP and CO2 and pyruvate carboxylase to form oxaloacetate
• ATP from fat breakdown when starving
• ox dehydrogenated to malate by malare dehydrogenase
• malate leaves mitochondria
• converted back to oxaloacetate using NAD plus
• Ox loses a phosphate group from GTP and C using phosphoenolpyruvate carboxylase to form phosphophenolpyruvate

Question 6

Bypass step 2

Answer 6

Fructose 1,6 – bisphosphate to fructose 6 – phosphate

Question 7

Both bypass 2 and original reaction are regulated by

Answer 7

Citrate & Fructose 2-6 bisphosphatase & AMP

Question 8

Why AMP reg?

Answer 8

when there’s an excess of AMP instead of ATP, obviously, the body is driven to make more glucose to make more ATP!

Question 9

Why citrate reg?

Answer 9

If there is excess of citrate, it tells us that the citric acid is being slow

Question 10

What enzyme acts in bypass 2

Answer 10

fructose 1-6 bisphophotase

Question 11

What inhibits the fructose 1,6 bisphosphatase

Answer 11

F 2,6 bisphotase

AMP

Question 12

What activates the fructose 1,6 bisphosphatase

Answer 12

citrate

Question 13

bypass 3

Answer 13

: glucose 6-phosphate to glucose

Question 14

what is the bypass step

Answer 14

instead of hexokinase

- • Glucose 6- phosphatase Hydrolyses Glucose 6 phosphate to remove the phosphate group

Question 15

Pyruvate can be formed from

Answer 15

o	Alanine 
o	Cytosine 
o	Glycine 
o	Serine 
o	Threonine

Question 16

• Phenylalanine & tyrosine can help form

Answer 16

fumarate – component in the TCA cycle – can form oxaloacetate

Question 17

Lactate as a glucose precursor (The Cori cycle):

Answer 17

lactate –> pyrivate by lactate behydrogenase

Question 18

glycerol as a glucose precursor

Answer 18

glycerol–> dihydroxyacetone phosphate

Question 19

enzymes in glycerol conversion

Answer 19

glycerol kinase and glycerol phosphate dehydrogenase

Question 20

cost of gluconeogenesis

Answer 20

6 ATPs and 2 NADHs

Question 21

When we’re starving, the energy comes from:

Answer 21

o Fat – Beta oxidation of fatty acids
o Protein muscle degradation – Degraded into amino acids which carbon skeletons can be oxidised to provide energy (& also provide carbon atoms to make glucose)