Podcast
Questions and Answers
Which tissues are known to require a continuous supply of glucose as a metabolic fuel?
Which tissues are known to require a continuous supply of glucose as a metabolic fuel?
What is the primary gluconeogenic precursor derived from the breakdown of triacylglycerols?
What is the primary gluconeogenic precursor derived from the breakdown of triacylglycerols?
Which enzyme is responsible for phosphorylating glycerol to form glycerol phosphate?
Which enzyme is responsible for phosphorylating glycerol to form glycerol phosphate?
During a prolonged fast, what percentage of gluconeogenesis is provided by the kidneys?
During a prolonged fast, what percentage of gluconeogenesis is provided by the kidneys?
Signup and view all the answers
Which molecules are known to be gluconeogenic precursors?
Which molecules are known to be gluconeogenic precursors?
Signup and view all the answers
In a normal overnight fast, what percentage of gluconeogenesis occurs in the liver?
In a normal overnight fast, what percentage of gluconeogenesis occurs in the liver?
Signup and view all the answers
Why does gluconeogenesis not simply involve the reversal of glycolysis?
Why does gluconeogenesis not simply involve the reversal of glycolysis?
Signup and view all the answers
What is the first step in converting glycerol to glucose via gluconeogenesis?
What is the first step in converting glycerol to glucose via gluconeogenesis?
Signup and view all the answers
What is the first step in gluconeogenesis when starting from pyruvate?
What is the first step in gluconeogenesis when starting from pyruvate?
Signup and view all the answers
What is the role of biotin in gluconeogenesis?
What is the role of biotin in gluconeogenesis?
Signup and view all the answers
Which of the following compounds cannot contribute to the net synthesis of glucose?
Which of the following compounds cannot contribute to the net synthesis of glucose?
Signup and view all the answers
Which molecule is primarily converted back to glucose in the liver during gluconeogenesis?
Which molecule is primarily converted back to glucose in the liver during gluconeogenesis?
Signup and view all the answers
Which amino acids are primarily responsible for supplying glucose during fasting?
Which amino acids are primarily responsible for supplying glucose during fasting?
Signup and view all the answers
Which of these statements best describes the reactions unique to gluconeogenesis?
Which of these statements best describes the reactions unique to gluconeogenesis?
Signup and view all the answers
What does the conversion of α-ketoglutarate in gluconeogenesis primarily yield?
What does the conversion of α-ketoglutarate in gluconeogenesis primarily yield?
Signup and view all the answers
In which cellular location does the carboxylation of pyruvate to oxaloacetate occur?
In which cellular location does the carboxylation of pyruvate to oxaloacetate occur?
Signup and view all the answers
Study Notes
Gluconeogenesis Overview
- Some tissues (brain, red blood cells, etc.) need a continuous glucose supply.
- Liver glycogen is a short-term source (10-18 hours).
- During extended periods without food, glucose is made from precursors like lactate, pyruvate, glycerol, and α-ketoacids.
- Gluconeogenesis is a specialized pathway, not a reversal of glycolysis.
- The liver primarily produces glucose (90%) during overnight fasts, with kidneys contributing 10% initially.
- During extended fasting, the kidneys become a major glucose source, contributing about 40% of total production.
Gluconeogenesis Substrates
- Gluconeogenic precursors are molecules used to synthesize glucose.
- These include glycolysis intermediates, TCA cycle intermediates, and α-keto acids.
- Glycerol, released from triacylglycerol breakdown in adipose tissue, is a crucial precursor.
- Glycerol is phosphorylated by glycerol kinase in the liver, forming glycerol phosphate.
- Glycerol phosphate is then oxidized to Dihydroxyacetone phosphate via glycerol phosphate dehydrogenase.
- Adipose lacks glycerol kinase, preventing the process there.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the processes and substrates involved in gluconeogenesis. This quiz covers the importance of glucose production in various tissues, key precursors, and the role of the liver and kidneys during fasting. Test your knowledge of this crucial metabolic pathway and its intermediates.
