Podcast
Questions and Answers
What is produced from the oxidative decarboxylation of pyruvate inside the mitochondria?
What is produced from the oxidative decarboxylation of pyruvate inside the mitochondria?
- 3-phosphoglycerate and ATP
- Lactate and CO2
- Acetyl-CoA and NADH (correct)
- ATP and FADH2
Where does the Krebs cycle occur?
Where does the Krebs cycle occur?
- Inner mitochondrial membrane
- Cytoplasm
- Mitochondrial matrix (correct)
- Outer mitochondrial membrane
Which process primarily generates ATP in the presence of oxygen?
Which process primarily generates ATP in the presence of oxygen?
- Substrate-level phosphorylation
- Fermentation
- Glycolysis
- Oxidative phosphorylation (correct)
What role does NADH play in the electron transport chain?
What role does NADH play in the electron transport chain?
Which substance is produced during the Krebs cycle along with NADH?
Which substance is produced during the Krebs cycle along with NADH?
What is the end product of glycolysis?
What is the end product of glycolysis?
How does the inner mitochondrial membrane contribute to ATP synthesis?
How does the inner mitochondrial membrane contribute to ATP synthesis?
What is the main source of glucose in gluconeogenesis?
What is the main source of glucose in gluconeogenesis?
Which of the following is NOT a function of NADH in cellular respiration?
Which of the following is NOT a function of NADH in cellular respiration?
Which of the following processes primarily occurs in the liver?
Which of the following processes primarily occurs in the liver?
What is the role of gluconeogenesis in energy metabolism?
What is the role of gluconeogenesis in energy metabolism?
During which condition does muscle metabolism switch to anaerobic glycolysis?
During which condition does muscle metabolism switch to anaerobic glycolysis?
What are ketone bodies produced from?
What are ketone bodies produced from?
What is the significance of the Cori cycle?
What is the significance of the Cori cycle?
Which transporter is primarily responsible for insulin-sensitive glucose uptake in muscle and adipose tissues?
Which transporter is primarily responsible for insulin-sensitive glucose uptake in muscle and adipose tissues?
What is the primary role of glucose-6-phosphate in glycolysis?
What is the primary role of glucose-6-phosphate in glycolysis?
Which of the following is NOT a substrate for gluconeogenesis?
Which of the following is NOT a substrate for gluconeogenesis?
Which metabolic pathway is responsible for producing ATP from the breakdown of fatty acids?
Which metabolic pathway is responsible for producing ATP from the breakdown of fatty acids?
What type of energy is required for gluconeogenesis?
What type of energy is required for gluconeogenesis?
What is the physiological response when blood glucose levels increase?
What is the physiological response when blood glucose levels increase?
Which of the following statements about the urea cycle is correct?
Which of the following statements about the urea cycle is correct?
Which enzyme is primarily responsible for the conversion of fructose-6-phosphate to fructose-1,6-bis-phosphate in glycolysis?
Which enzyme is primarily responsible for the conversion of fructose-6-phosphate to fructose-1,6-bis-phosphate in glycolysis?
What is the primary role of the electron transport chain in cellular metabolism?
What is the primary role of the electron transport chain in cellular metabolism?
Which glucose transporter has the highest affinity for glucose?
Which glucose transporter has the highest affinity for glucose?
What is the primary purpose of deamination in amino acid metabolism?
What is the primary purpose of deamination in amino acid metabolism?
Which compound is produced during the urea cycle and released into the bloodstream?
Which compound is produced during the urea cycle and released into the bloodstream?
Which amino acid is NOT an energy source for most tissues?
Which amino acid is NOT an energy source for most tissues?
What is the primary nitrogen-containing compound excreted through the kidneys?
What is the primary nitrogen-containing compound excreted through the kidneys?
Which statement about fatty acid metabolism in tissues is accurate?
Which statement about fatty acid metabolism in tissues is accurate?
Which amino acid is considered an essential one that must be obtained through diet?
Which amino acid is considered an essential one that must be obtained through diet?
What process allows amino acids to enter the Krebs cycle?
What process allows amino acids to enter the Krebs cycle?
Which of the following amino acids is primarily involved in the urea cycle?
Which of the following amino acids is primarily involved in the urea cycle?
What is the primary role of NADH in the tricarboxylic acid cycle?
What is the primary role of NADH in the tricarboxylic acid cycle?
In the context of β-oxidation of fatty acids, what is produced as a byproduct?
In the context of β-oxidation of fatty acids, what is produced as a byproduct?
Which molecule is formed when acetyl-CoA enters the tricarboxylic acid cycle?
Which molecule is formed when acetyl-CoA enters the tricarboxylic acid cycle?
What is a major purpose of the tricarboxylic acid cycle?
What is a major purpose of the tricarboxylic acid cycle?
Which enzyme is responsible for the conversion of succinyl-CoA to succinate, producing GTP in the process?
Which enzyme is responsible for the conversion of succinyl-CoA to succinate, producing GTP in the process?
What compound is regenerated in the final steps of the tricarboxylic acid cycle?
What compound is regenerated in the final steps of the tricarboxylic acid cycle?
Which type of molecule is primarily oxidized during β-oxidation?
Which type of molecule is primarily oxidized during β-oxidation?
What is the net gain of NADH and FADH2 during one cycle of β-oxidation of a saturated fatty acid?
What is the net gain of NADH and FADH2 during one cycle of β-oxidation of a saturated fatty acid?
Study Notes
Learning Outcomes
- Glycolysis: Breakdown of glucose to pyruvate
- Oxidative decarboxylation: Conversion of pyruvate to acetyl-CoA
- Krebs cycle: Oxidation of acetyl-CoA to produce NADH and FADH2
- β-oxidation of fatty acids: Breakdown of fatty acids to acetyl-CoA
- Electron transport chain and ATP synthesis: Production of ATP using the energy from electrons
- Energy storage and utilisation of stores: Processes for storing and using glucose, fatty acids, and glycogen
- Gluconeogenesis: Synthesis of glucose from non-carbohydrate sources
- Urea cycle: Breakdown of ammonia to urea
- Roles of different organs: Liver, kidneys, and muscle in metabolism
Metabolic Response to Food
- Increased blood glucose stimulates insulin secretion from pancreatic beta cells
- Insulin promotes glucose uptake by cells
Glucose Transporters
- GLUT-1: Basal glucose uptake in RBCs, brain, and most tissues (high affinity)
- GLUT-2: Glucose sensing in liver and pancreatic beta cells (low affinity)
- GLUT-3: Glucose uptake in brain, intestine, and placenta
- GLUT-4: Insulin-sensitive glucose uptake in muscle and adipose tissue
- GLUT-5: Fructose uptake in the intestine
- SGLT-1: Active transport of glucose and sodium in the intestine and kidney
Glycolysis
- Breakdown of glucose to pyruvate
- Occurs in the cytoplasm
- Produces 2 ATP, 2 pyruvate, and 2 NADH
Mitochondria – Oxidative Phosphorylation
- Most ATP production takes place in the mitochondria
- Krebs cycle occurs in the mitochondrial matrix
- Electron transport chain is located on the inner mitochondrial membrane
Oxidative Decarboxylation
- Conversion of pyruvate to acetyl-CoA
- Occurs in the mitochondria
- Produces NADH
Oxidative Phosphorylation
- Electron transport chain utilizes NADH and FADH2 to produce ATP
- Acetyl-CoA is used in the Krebs cycle to generate NADH and FADH2
Krebs Cycle
- Also known as the citric acid cycle or tricarboxylic acid cycle
- Oxidation of acetyl-CoA to produce NADH and FADH2
β-oxidation of Fatty Acids
- Breakdown of fatty acids to acetyl-CoA
- Produces FADH2 and NADH
Production of NADH and FADH2
- Triglycerides are broken down by lipolysis, generating free fatty acids and glycerol
- β-oxidation of fatty acids produces FADH2 and NADH
- Glycolysis produces NADH
Utilisation of Energy Stores
- Glucose stored as glycogen in the liver and skeletal muscle
- Glycogenolysis breaks down glycogen to glucose-6-P
- Gluconeogenesis converts glycerol, lactate, and amino acids to glucose
- Triglycerides are broken down by lipolysis, producing fatty acids and glycerol
- β-oxidation of fatty acids produces acetyl-CoA
- Ketone bodies are produced from fatty acids in the liver
Gluconeogenesis
- Synthesis of glucose from non-carbohydrate sources
- Occurs mainly in the liver
- Uses glycerol, lactate, and amino acids as substrates
The Cori Cycle
- Lactate produced during anaerobic glycolysis is transported to the liver
- Gluconeogenesis converts lactate back to glucose
- Requires energy to regenerate glucose
Biosynthetic Roles of the Krebs Cycle
- Precursors for amino acid biosynthesis from intermediates in the Krebs cycle
Amino Acid Metabolism
- Amino acids require deamination (removal of the amino group) before being used for glucose/lipid synthesis
- Urea is produced in the liver via the urea cycle
Urea Cycle and Krebs Cycle
- Amino acids are broken down into urea via the urea cycle
- Intermediates from the urea cycle can be used in the Krebs cycle
Tissue Variations in Energy Source
- Glucose is the main energy source for most tissues, essential for brain and RBCs
- Fatty acids are used by most tissues, except for neurons
- Ketones can be used by most tissues
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Description
This quiz covers key topics in metabolism, including glycolysis, the Krebs cycle, and the urea cycle. It highlights the roles of various organs in metabolism and examines glucose transporters. Test your understanding of how energy is produced and utilized in the body.
