Biochemistry LE 2: Gluconeogenesis

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What happens to the glycerol backbone in response to low insulin and high glucagon levels?

It is excreted from the body

It enters gluconeogenesis (correct)

It is stored in the liver

It is converted to glucose

Which amino acid is not glucogenic?

Glutamate

Leucine (correct)

Aspartate

Alanine

What is the intermediate that Aspartate and Asparagine enter gluconeogenesis through?

a-ketoglutarate

Oxaloacetate (correct)

Pyruvate

Fumarate

What is the enzyme that converts alanine to pyruvate?

Alanine aminotransferase Signup and view all the answers

What is the fate of Tyrosine, Phenylalanine, and Aspartate in gluconeogenesis?

They are converted to Fumarate Signup and view all the answers

What is the purpose of gluconeogenesis in the body?

To maintain glucose homeostasis during fasting or low carbohydrate intake Signup and view all the answers

What is the intermediate that Arginine, Glutamate, Glutamine, Histamine, and Proline are converted to in gluconeogenesis?

a-ketoglutarate Signup and view all the answers

What is the process by which alanine is sent to the liver during starvation?

Glucose-Alanine cycle Signup and view all the answers

What is the purpose of the Glucose-Alanine cycle?

To convert amino acids to glucose Signup and view all the answers

What is the major substrate of anaerobic metabolism in actively exercising muscles?

Lactate Signup and view all the answers

What is the enzyme involved in the reaction of lactate reoxidization to pyruvate?

Lactate dehydrogenase Signup and view all the answers

Why can't pyruvate be directly converted back to PEP?

Because it is inside the mitochondria Signup and view all the answers

What is the role of the malate-aspartate transporter in the Cori cycle?

To transport malate out of the mitochondria Signup and view all the answers

What happens to lactate during prolonged activity in the RBC?

It is transported back to the liver and into the kidneys Signup and view all the answers

What is the enzyme that catalyzes the dephosphorylation of Glucose-6-phosphate to produce glucose?

Glucose-6-phosphatase (G6Pase) Signup and view all the answers

What is the net cost of the Cori cycle in terms of phosphate?

4 phosphate Signup and view all the answers

What is the final step in gluconeogenesis and glycogenolysis?

Dephosphorylation of Glucose-6-phosphate Signup and view all the answers

What is the end product of the process described?

Pyruvate Signup and view all the answers

What is the purpose of the Cori cycle in the body?

To get rid of lactic acid produced in the muscle Signup and view all the answers

How many ATP molecules are gained in the process?

2 ATP Signup and view all the answers

What is the intermediate step in the conversion of lactate to glucose in the liver?

Malate Signup and view all the answers

Where does the final step of gluconeogenesis and glycogenolysis occur?

Endoplasmic Reticulum (ER) Lumen Signup and view all the answers

What enzyme is responsible for converting Pyruvate to Lactic Acid?

Lactate Dehydrogenase Signup and view all the answers

Where is the final product of the Cori cycle utilized?

In the muscle Signup and view all the answers

What is the function of GLUT2 transporter?

To transport glucose in the bloodstream Signup and view all the answers

Why is Lactate Dehydrogenase necessary?

To unload NADH and convert it to NAD+ Signup and view all the answers

What is the product of the reaction catalyzed by cytosolic malate dehydrogenase?

Oxaloacetate Signup and view all the answers

What is the fate of Lactic Acid in the liver?

It is oxidized and reconverted into Pyruvate Signup and view all the answers

What is the function of the malate-aspartate shuttle?

To transport malate out of the mitochondria Signup and view all the answers

What is the substrate for the reaction catalyzed by cytosolic malate dehydrogenase?

Malate Signup and view all the answers

What is the result of Glucose 6-Phosphatase enzyme acting on Glucose 6-phosphate?

Phosphate is released from G6P Signup and view all the answers

What is the result of the reaction catalyzed by phosphoenolpyruvate carboxykinase (PEPCK)?

Removal of CO2 and addition of Phosphate ion Signup and view all the answers

Where is Glucose 6-Phosphatase enzyme found?

In the liver, kidney, and GIT tissues Signup and view all the answers

What is the role of GLUT 2 transporters?

To transport free Glucose out of the Endoplasmic Reticulum of the liver Signup and view all the answers

What is the enzyme that converts oxaloacetate to Phosphoenolpyruvate (PEP)?

Phosphoenolpyruvate carboxykinase (PEPCK) Signup and view all the answers

What is the final product that is returned into the bloodstream?

Free Glucose Signup and view all the answers

What is the enzyme responsible for converting Glucose 6-Phosphate to Fructose 6-Phosphate in Glycolysis?

Phosphoglucoisomerase Signup and view all the answers

Where is Glucose 6-Phosphate transported to for dephosphorylation?

Endoplasmic Reticulum Signup and view all the answers

What happens to the phosphate group of Glucose 6-Phosphate in the Endoplasmic Reticulum?

It is cleaved and dephosphorylated Signup and view all the answers

What is the fate of glucose once it is in the Endoplasmic Reticulum?

All of the above Signup and view all the answers

What is the purpose of Glucose 6-phosphatase in gluconeogenesis?

To add glucose into the blood Signup and view all the answers

What is the byproduct of the reaction catalyzed by Glucose 6-phosphatase?

Free glucose Signup and view all the answers

What happens to the glucose produced in the Endoplasmic Reticulum?

It is transported to the cell surface and to the bloodstream Signup and view all the answers

What is the energy yield of the reaction catalyzed by Glucose 6-phosphatase?

Low energy phosphate bond Signup and view all the answers

What is the source of glucose that enters glycolysis through Glyceraldehyde 3-Phosphate?

Diet → Fructose → Glycolysis Signup and view all the answers