75 Questions
Which process involves converting other carbohydrates to glucose, but is not considered as gluconeogenesis?
Glycogenesis
What is the primary substrate used in gluconeogenesis?
Carbohydrates
Which process involves breaking down glycogen to release glucose into the bloodstream?
Glycogenolysis
In the context provided, what process specifically refers to the conversion of non-carbohydrate sources to glucose?
Gluconeogenesis
Which metabolic pathway involves the breakdown of glucose into pyruvate?
Glycolysis
What is the precursor for entering the glucogenic pathway?
Alanine
What transformation does alanine undergo to enter the glucogenic pathway?
Transamination
Which keto acid does alanine become after transamination?
Pyruvate
What is the easiest amino acid to enter into the glucogenic pathway?
Alanine
Which metabolic pathway does alanine enter after transamination?
Gluconeogenesis
What is the first step in the process described?
High concentration
What does the compound attach to in the process?
GPCR
Which step results in the activation of cAMP synthesis?
Attaching to GPCR
What is the final step in the described process?
Protein kinase A attachment
Which component is responsible for activating protein kinase A in the process?
cAMP synthesis
What is the main difference between the enzymes in glycolysis and gluconeogenesis?
Enzymes in glycolysis have a positive ΔG in phosphorylation, while enzymes in gluconeogenesis have a negative ΔG.
Where does the process described occur, according to the text?
Kidney and liver
What molecule provides both energy and a phosphate group for the phosphorylation of glucose in glycolysis?
ATP
Why is it necessary to couple the phosphorylation in glycolysis with ATP hydrolysis?
To generate a negative net ΔG
Which of the following organs does NOT play a role in the process described?
Pancreas
What are the products when 1,3 bisphosphoglycerate is converted to glyceraldehyde 3-P during gluconeogenesis?
Inorganic phosphate, 2 NAD+
What happens when 3-phosphoglycerate is converted to 1,3 bis-phosphoglycerate in gluconeogenesis?
2 ATP are hydrolyzed to 2 ADP
Which molecules are oxidized into NAD+ during gluconeogenesis?
NADH
What role does inorganic phosphate play in the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P?
It is released
How many ATP molecules are hydrolyzed to ADP during the conversion of 3-phosphoglycerate to 1,3 bis-phosphoglycerate?
2 ATP
Where does gluconeogenesis occur?
Kidneys
Which component is NOT involved in gluconeogenesis?
Heart
When does gluconeogenesis primarily take place?
During fasting or starvation
Which of the following is NOT a site where gluconeogenesis occurs?
Skeletal muscle
Besides the liver and kidneys, where else can gluconeogenesis occur?
Spleen
What happens to glycerol once it is released from the adipocytes?
It travels through the bloodstream on albumin
How are fatty acids transported in the bloodstream?
Bound to lipoproteins
What do different cell types primarily use fatty acids for?
Energy production
Which protein serves as a carrier for glycerol in the bloodstream?
Albumin
How is glycerol related to the breakdown of fatty acids?
Glycerol is a byproduct of fatty acid breakdown
Which process involves the synthesis of glucose from non-carbohydrate sources?
Gluconeogenesis
What is the primary role of gluconeogenesis in metabolism?
Converting pyruvate into glucose
What is the fate of alanine after undergoing transamination?
Converted into glyceraldehyde 3-phosphate for gluconeogenesis
Which organ primarily regulates the process of gluconeogenesis in the body?
Liver
What is the key purpose of gluconeogenesis in terms of maintaining blood glucose levels?
To stabilize blood glucose levels during fasting or starvation
What is the function of Glucose 6-phosphatase in relation to Hexokinase/Glucokinase?
Catalyzes the breakdown of glucose 6-phosphate
Where does Glucose 6-phosphatase function in the cell?
Endoplasmic reticulum
Which transporter is responsible for transporting glucose from the endoplasmic reticulum to the cytosol in hepatocytes/kidney cells?
Glute 7 transporter
After exiting the cell, how does glucose reach the bloodstream?
Through other types of glucose transporters
What is the role of Hexokinase/Glucokinase in this process?
Converts glucose to glucose 6-phosphate in the cytosol
Why is acetyl CoA specifically mentioned as the activator for pyruvate carboxylase?
Acetyl CoA is produced in large amounts during fatty acid degradation in fasting state
What happens to the excess acetyl CoA that cannot be utilized by the Krebs cycle in fasting conditions?
It accumulates and activates pyruvate carboxylase
In the context provided, what role does pyruvate carboxylase play in gluconeogenesis?
It catalyzes the conversion of pyruvate to oxaloacetate
What metabolic state of the cell triggers the activation of pyruvate carboxylase by acetyl CoA?
Fasting state
Why does the cell require the activation of pyruvate carboxylase during fasting?
To generate glucose from non-carbohydrate sources like fatty acids
Why is ATP not used in the dephosphorylation of Glucose 6-phosphate?
The phosphatase enzyme has a negative ΔG.
What drives the dephosphorylation of Glucose 6-phosphate by the phosphatase enzyme?
Negative ΔG
In the context of the text, what is the significance of the negative ΔG in the dephosphorylation reaction?
It facilitates the conversion of Glucose 6-phosphate without ATP.
Why does dephosphorylation of Glucose 6-phosphate not utilize ATP despite being an energy-requiring process?
Presence of a negative ΔG
What metabolic condition would likely alter the need for ATP in the dephosphorylation of Glucose 6-phosphate?
Starvation state
What is the enzyme responsible for converting Phosphoenolpyruvate to pyruvate in the final step of glycolysis?
Phosphofructokinase
In gluconeogenesis, which enzyme catalyzes the conversion of pyruvate to Phosphoenolpyruvate, the reverse reaction of the last step in glycolysis?
Hexokinase
Which molecule serves as the precursor for the synthesis of Phosphoenolpyruvate from pyruvate in gluconeogenesis?
Malonyl-CoA
Which of the following enzymes is NOT directly involved in the conversion of Phosphoenolpyruvate to pyruvate in glycolysis or its reverse reaction in gluconeogenesis?
Fructose-1,6-bisphosphatase
Which of the following statements regarding Pyruvate kinase is INCORRECT in the context of glycolysis and gluconeogenesis?
Pyruvate kinase is activated by fructose-6-phosphate in gluconeogenesis.
What is the initial reaction that takes place in mitochondria involving pyruvate?
Conversion of pyruvate to oxaloacetate by pyruvate carboxylase
Why is pyruvate carboxylase activation essential during fasting?
To convert excess acetyl CoA into pyruvate for energy production
What is the role of oxaloacetate in the context of pyruvate metabolism?
It reacts with acetyl-CoA to form citrate in the TCA cycle
Which enzyme is responsible for catalyzing the conversion of pyruvate to oxaloacetate in the mitochondria?
Pyruvate carboxylase
Which substance is produced as a result of the reaction catalyzed by pyruvate carboxylase?
Oxaloacetate
What is the fate of inorganic phosphate in the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P during gluconeogenesis?
It is consumed by the reaction
What is the ultimate outcome of the ATP molecules hydrolyzed to ADP during the conversion of 3-phosphoglycerate to 1,3 bisphosphoglycerate in gluconeogenesis?
They are used for cellular respiration
What is the function of 1,3 bisphosphoglycerate in the context of gluconeogenesis?
Serves as a carrier of high-energy phosphate bonds
How does NADH contribute to the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P?
It provides electrons to reduce NAD+
What is the primary role of NAD+ in the context of gluconeogenesis?
To carry electrons from NADH
What is the primary function of Glucose 6-phosphatase in gluconeogenesis?
Converting glucose 6-phosphate back to glucose
Which type of transporters are responsible for facilitating the exit of glucose from hepatocytes/kidney cells in gluconeogenesis?
Fructose transporters
What is the enzyme responsible for transporting glucose from the endoplasmic reticulum to the cytosol in hepatocytes/kidney cells during gluconeogenesis?
Glute 7
What is the main difference between Glucose 6-phosphatase and Hexokinase/Glucokinase in terms of their roles in glucose metabolism?
Glucose 6-phosphatase converts glucose back to glucose 6-phosphate while Hexokinase/Glucokinase phosphorylate glucose
In the context of gluconeogenesis, what is the primary role of Glute 7 existing on the ER membrane?
Facilitating the entry of glucose into the cell
Learn about the pathway where alanine is converted into pyruvate, involving transamination and the removal of amino groups. Discover where this process takes place in the body.
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