Module 5-6 Review ChatGPT Flashcards
What are the primary fuel sources in myocytes, neurons, and erythrocytes during a keto diet
Fatty acids in myocytes, ketone bodies in neurons, and glucose in erythrocytes
What is the primary fuel used by the brain during prolonged fasting
Ketone bodies
What are the 4 main promoting and 2 inhibitory effects of insulin in the fed state
Glucose uptake, glycogen synthesis, lipogenesis, and protein synthesis
Gluconeogenesis and glycogenolysis
What triggers glycogenolysis and gluconeogenesis during fasting
The release of glucagon and epinephrine
What is the role of glucagon during prolonged fasting
Lipolysis
Ketogenesis
Gluconeogenesis
What are the main differences between saturated and unsaturated fats
Saturated fats have no double bonds and are typically solid at room temperature, while unsaturated fats have one or more double bonds and are typically liquid
What promoting (3) and inhibitory (1) effects does cortisol have on metabolism
Gluconeogenesis, proteolysis, and lipolysis
Glucose uptake in peripheral tissues
What promoting (2) and inhibitory (1) roles does epinephrine play in fuel mobilization
Rapidly mobilizes energy by increasing glycogenolysis and lipolysis
Insulin secretion
What is the significance of malonyl-CoA in fatty acid metabolism
Malonyl-CoA inhibits carnitine palmitoyltransferase I (CPT I), preventing fatty acid oxidation
What is the function of the pyruvate dehydrogenase complex
The pyruvate dehydrogenase complex converts pyruvate to acetyl-CoA, linking glycolysis to the TCA cycle
What effect does arsenic have on pyruvate dehydrogenase
Arsenic inhibits the pyruvate dehydrogenase complex by binding to dihydrolipoamide, leading to reduced activity and lactic acidosis
What is the result of a deficiency in glucose-6-phosphate dehydrogenase (G6PD)
G6PD deficiency leads to hemolytic anemia, especially under oxidative stress, due to impaired NADPH production
What are the key points to remember about the TCA cycle
The TCA cycle generates NADH and FADH2 for the electron transport chain, produces GTP/ATP, and is crucial for energy production
What are the effects of electron transport chain (ETC) uncoupling
ETC uncoupling dissipates the proton gradient as heat, reducing ATP production and increasing thermogenesis
What are the key inhibitors of Complex I in the ETC
Rotenone and Amytal
What are the key enzymes that circumvent gluconeogenesis
Pyruvate carboxylase, PEPCK, fructose-1,6-bisphosphatase, and glucose-6-phosphatase
What is the significance of fructose 2,6-bisphosphate in metabolism
Fructose 2,6-bisphosphate regulates glycolysis and gluconeogenesis, activated by insulin and inhibited by glucagon
What is the role of insulin in glycogen metabolism
Insulin stimulates glycogen synthesis and inhibits glycogenolysis
What are the primary effects of glucagon and epinephrine on glycogen metabolism
Both hormones stimulate glycogenolysis and inhibit glycogen synthesis
What is the role of fatty acid synthase
Fatty acid synthase catalyzes the synthesis of fatty acids from acetyl-CoA and malonyl-CoA in the cytoplasm
What is the impact of a deficiency in medium-chain acyl-CoA dehydrogenase (MCAD)
MCAD deficiency leads to hypoglycemia and the accumulation of medium-chain fatty acids during fasting or illness
What enzyme is deficient in phenylketonuria (PKU)
Phenylalanine hydroxylase
What are the symptoms of maple syrup urine disease (MSUD)
Sweet-smelling urine, lethargy, poor feeding, vomiting, and developmental delay
What causes hyperammonemia in urea cycle disorders
Deficiencies in enzymes like ornithine transcarbamylase (OTC) or carbamoyl phosphate synthetase (CPS) lead to the accumulation of ammonia
What is the function of carbamoyl phosphate synthetase I (CPS I) in the urea cycle
CPS I catalyzes the formation of carbamoyl phosphate from ammonia and bicarbonate, the first step in the urea cycle
What are the clinical features of ornithine transcarbamylase (OTC) deficiency
Hyperammonemia, orotic aciduria, lethargy, and cerebral edema
What is the role of lipoprotein lipase (LPL) in lipid metabolism
LPL hydrolyzes triglycerides in chylomicrons and VLDL into free fatty acids and glycerol, facilitating their uptake by tissues
What is the significance of ApoB-100 in lipoprotein metabolism
ApoB-100 is essential for the synthesis and clearance of VLDL, IDL, and LDL
What are the clinical features of familial hypercholesterolemia
Elevated LDL cholesterol, tendon xanthomas, and an increased risk of atherosclerosis
What is the impact of statins on cholesterol synthesis
Statins inhibit HMG-CoA reductase, reducing cholesterol synthesis and increasing LDL clearance from the bloodstream
What are the consequences of uncoupling protein (UCP) activity
UCPs dissipate the proton gradient in mitochondria, leading to heat generation instead of ATP production
What is the main source of energy during the fed state
Glucose is the main source of energy during the fed state
What are the key metabolic pathways activated during the fed state
Glycolysis, glycogenesis, and lipogenesis are activated during the fed state
What is the role of insulin in the fed state
Insulin promotes glucose uptake, glycogen synthesis, and fat storage, while inhibiting gluconeogenesis and glycogenolysis
How does the liver respond to insulin during the fed state
The liver increases glycogen synthesis and decreases glucose production through gluconeogenesis
What is the primary function of the pentose phosphate pathway
The pentose phosphate pathway generates NADPH and ribose-5-phosphate for nucleotide synthesis and reductive biosynthesis
What are the key enzymes of the pentose phosphate pathway
Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase are key enzymes of the pentose phosphate pathway
What happens during the oxidative phase of the pentose phosphate pathway
NADPH is generated, which is essential for fatty acid synthesis and maintaining reduced glutathione levels
What is the role of NADPH in red blood cells
NADPH is crucial for maintaining reduced glutathione levels, which protect red blood cells from oxidative damage
What triggers the non-oxidative phase of the pentose phosphate pathway
The non-oxidative phase is triggered when the cell needs ribose-5-phosphate for nucleotide synthesis
What is the impact of a deficiency in glucose-6-phosphate dehydrogenase (G6PD)
G6PD deficiency leads to reduced NADPH production, making red blood cells more susceptible to oxidative stress and hemolysis
What is the role of fructose-2,6-bisphosphate in glycolysis
Fructose-2,6-bisphosphate activates phosphofructokinase-1 (PFK-1), enhancing glycolysis
How is fructose-2,6-bisphosphate regulated
Fructose-2,6-bisphosphate levels are regulated by insulin (which increases it) and glucagon (which decreases it)
What is the function of pyruvate dehydrogenase (PDH) in energy metabolism
PDH converts pyruvate to acetyl-CoA, linking glycolysis to the TCA cycle
What regulates pyruvate dehydrogenase activity
PDH is activated by ADP and inhibited by ATP, NADH, and acetyl-CoA
What is the role of the TCA cycle in cellular respiration
The TCA cycle generates NADH and FADH2, which are used in the electron transport chain to produce ATP
What are the key products of one turn of the TCA cycle
One turn of the TCA cycle produces 3 NADH, 1 FADH2, 1 GTP (or ATP), and 2 CO2 molecules
What is the importance of alpha-ketoglutarate in the TCA cycle
Alpha-ketoglutarate is a key intermediate that can be used for amino acid synthesis and energy production
What enzyme converts succinate to fumarate in the TCA cycle
Succinate dehydrogenase converts succinate to fumarate, and it is also part of Complex II in the electron transport chain
What is the role of citrate in metabolism
Citrate can be used in the TCA cycle, or transported to the cytoplasm for fatty acid and cholesterol synthesis
What is the significance of the malate-aspartate shuttle
The malate-aspartate shuttle transfers reducing equivalents (NADH) from the cytoplasm into the mitochondria for ATP production
What is the function of the electron transport chain (ETC)
The ETC transfers electrons from NADH and FADH2 to oxygen, driving the synthesis of ATP through oxidative phosphorylation
What is the role of Complex IV in the electron transport chain
Complex IV (cytochrome c oxidase) transfers electrons to oxygen, the final electron acceptor, forming water
Pumps protons
What happens during oxidative phosphorylation
During oxidative phosphorylation, the energy from electron transfer in the ETC is used to pump protons across the mitochondrial membrane, creating a gradient that drives ATP synthesis
What are the effects of ETC uncoupling on cellular metabolism
ETC uncoupling dissipates the proton gradient as heat, reducing ATP production and increasing thermogenesis
What is the function of ATP synthase in mitochondria
ATP synthase uses the proton gradient generated by the ETC to convert ADP and inorganic phosphate into ATP
What are the consequences of a deficiency in pyruvate dehydrogenase (PDH)
PDH deficiency leads to lactic acidosis, neurodevelopmental delay, and decreased energy production
What role does the enzyme hexokinase play in glycolysis
Hexokinase phosphorylates glucose to form glucose-6-phosphate, the first step in glycolysis
What is the function of phosphofructokinase-1 (PFK-1) in glycolysis
PFK-1 is the rate-limiting enzyme in glycolysis, converting fructose-6-phosphate to fructose-1,6-bisphosphate
What activates and inhibits phosphofructokinase-1 (PFK-1)
PFK-1 is activated by AMP and fructose-2,6-bisphosphate and inhibited by ATP and citrate
What is the role of pyruvate kinase in glycolysis
Pyruvate kinase catalyzes the final step in glycolysis, converting phosphoenolpyruvate (PEP) to pyruvate and generating ATP