Gluconeogenesis, Fatty Acid Synthesis, and Glycogen Synthesis (and breakdown) Flashcards Preview

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Flashcards in Gluconeogenesis, Fatty Acid Synthesis, and Glycogen Synthesis (and breakdown) Deck (35):

What is Gluconeogenesis overall?

Gluconeogenesis is the reverse of Glycolysis and is the synthesis of Glucose.
This is to ensure that the blood glucose levels are constant in the bloodstream if there is not enough in the blood stream.


Which two organs does Gluconeogenesis occur?

Primarily liver, somewhat in the Kidney


What is a glitch that needs to be overcome during Gluconeogenesis?

The steps that are very energy favorable in Glycolysis, but energy unfavorable for Gluconeogenesis.

Step 1, 2, and last step of Glycolysis


What is the first step of Gluconeogenesis?

Pyruvate (3C) is turned into Oxaloacetate,(4C), via Pyruvate carboxylate

2ATP used


What is the second step for Gluconeogenesis?

Oxaloacetate is turned into Phosphoenol Pyruvate via PEPCK)

2 GTP used


What is the step after the 2nd step of Gluconeogenesis

In order to go from PEP to G-3-P,
2 ATP are used and 2 NADH is used.


What is the 3rd step of Gluconeogenesis?

G-3-P turns into Fructose 1,6 BisPhosphate


What is the 4th Step of Gluconeogenesis?

Fructose 1,6 Bisphosphate turns into Fructose -6-Phosphate via Fructose 1, 6 Bisphosphatase


What is the 5th Step of Gluconeogensis?

Fructose 6-Phosphate turns into Glucose -6 phosphate


What is the 6th step of Gluconeogenesis?

Glucose 6-Phohsphate turns into Glucose via Glucose 1, 6 BisPhosphatase


How does cell prevent reciprocal processes from occurring?

The prevents this via Hormones and intermediates that direct/inhibit glycolysis and/or Gluconeogenesis


Name 2 intermediates that block Glycolysis?

ATP, Citrate
They inhibit PFK, and stimulate Fructose 1, 6 Bisphosphatase


Name a hormone that encourages Glycolysis?

Explain the "pathway" that this hormone causes

Insulin positively regulates Fructose 2, 6 Bisphosphate, which in turn positively regulates PFK, which increases Glycolysis.


What inhibits Fructose 2, 6 Bisphosphate?

Glucagon, which is activated during times of low blood glucose.


Where in the cell does gluconeogenesis occur?

Mainly in cytoplasm, sometimes in the mitochondria


What is the process of taking glucose and putting it in it's storage form?



What conditions cause Glycogenesis

High blood glucose


Which hormone cause Glycogenesis to occur?



Where is Glycogen stored mainly in?

Mainly in the liver, to some extent in the skeletal muscle


What is the first step of Glycogenesis?

The first step of glycogenesis is: The conversion of Glucose 6-P to Glucose 1 -P via the enzyme Phosphoglucomutase


What is the second step of glycogenesis?

UTP comes on and attaches itself to Glucose 1 -P. Glycogen Synthase removed UDP, and the Glyucose 1 -P is attached to the growing Glycogen chain via Glycogen Synthase


What are the starting materials of Fatty Acid Synthesis?

The starting points for fatty acid synthesis are
1) Acetyl Co-A
2) Malonyl Co-A

Acetyl Co-A turns into Malonyl


Describe the structures of acetyl Coa and Malonyl Coa, respectively

Acetyl Coa is an Acetyl group with a Co-A group attached to it.
Malonyl Co-A is when the aklyl group on the acetyl CoA is attached with a carboxylic Acid group. (1 ATP used)


What is the enzyme that helps in the process of fatty acid synthesis

Fatty acid Synthase Enzyme


What specific part of the fatty acid synthase enzyme is involved in the process of synthesizing fatty acids?

It is the Acyl Carrier Protein (ACP) domain, and a Cysteine domain
(both have -SH)


Describe process by which fatty acid synthesis occurs?

Acetyl Co-A attaches to the ACP domain and then goes down towards Cystein domain.
Malonyl Co-A then goes to the ACP domain.
CO2 is released from the Malonyl Coa as it joins Acetyl Co-A at the bottom
2NADPH are changed to 2NADP+, and then this in turn reduces the carbonyl carbon on Malonyl Co-A completely


Where are fatty acids synthesized?

In the cytosol


Where does beta-oxidation occur?

The attachment of -S-CoA to the fatty acid occurs in the outer mitochondrial membrane, while the breakdown of this compound then occurs in the matrix of the mitochondria.


What happens in the outer mitochondrial membrane part of the fatty acid synthesis?

-2-CoA is attached to Fatty acids. This uses up an equivalent of 2 ATP (1 ATP turns to 1AMP)


What happens after fatty acids are attached with -S-CoA in the outer mitochondrial membrane?

The resulting Fatty -Acyl CoA's are transported to the mitochondrial matrix, where they undergo B-Oxidation


Describe the steps for B oxidation

B-Oxidation starts when alpha and beta carbon are oxidized, and a double bond exists between the two. FAD+ turns into FADH2.

After this step, H2O reduces Beta carbon by adding an OH group to it, and the alpha carbon by adding an H to it.

Then Beta carbon is reduced again by NAD+ to NADH conversion, and beta carbon turns into carbonyl group

Lastly, Thiolase, by adding -S-CoA to the to the Beta Carbon, and thereby releasing Acetyl COa (from the Alpha carbon) to the Kreb's Cycle, which also occurs in the mitochondrial matrix


What is the point of ketogenesis?

The point of ketogenesis is tocreate ketoacids which can then go into the Kreb's Cycle (especially in the brain) and provide a source of energy in times of glucose starvation.


Where does ketogenesis occur?

Ketogenesis occurs in the mitochondrial matrix.


Describe the steps of Ketogenesis

2 Acetyl Co-A come together to make a ketone with one R group which is a methyl group and 1 R group which is an Acetyl Co-A

Then, another Acetyl Co-A +H2O is added to this "ketone", the CoA-SH R group on the first group leaves, and Acetyl Co-A replaces it. H2O oxidized the carbon which lost the CoA-SH in the last step.
Acetyl Co-Co-A that was added is lost once again, leaving Acetoacetate.

Acetoacetate can turn into acetone (most basic ketone), or turn into B-Hydroxybutyrate.


Describe the process of glycogenolysis

Glycogeolysis starts with Glycogen phosphorylase adding a phosphate to Glucose at the 6th carbon. Phospho-glucoisomerase turns this G-1-P into G-6-P.
Glucose-6-P phosphatase then converts this to pure glucose.