25 Questions
What is the byproduct of the reduction of pyruvate in anaerobic glycolysis?
Lactate
What is the stage of glycolysis where ATP is produced?
Oxido-Reduction state
What is the purpose of anaerobic glycolysis in exercising skeletal muscle?
To generate ATP in the absence of oxygen
What is the fate of lactate produced in muscle tissue during intense exercise?
It is diffused into the bloodstream and used by the liver to make glucose
What is the net ATP production in the glycolytic pathway?
Two molecules of ATP
What is the enzyme responsible for the conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate?
Glyceraldehyde 3-phosphate dehydrogenase
What is the process by which the liver converts lactate to glucose?
Gluconeogenesis
What is the stage of glycolysis where phosphorylated forms of intermediates are synthesized?
Phosphorylation state
What is the result of lactate accumulation in muscle tissue during intense exercise?
A decrease in intracellular pH
What is the purpose of the enzyme glucose 6-phosphatase?
To convert glucose 6-phosphate to glucose
What is the primary function of the glycolytic pathway in all tissues?
To break down glucose to provide energy and intermediates
What is the significance of glycolysis in the absence of oxygen?
It allows skeletal muscle to perform at high levels of work output
What are the two transport mechanisms by which glucose enters cells?
Na+-independent, facilitated diffusion transport system and Na+-dependent monosaccharide cotransporter system
What is the end product of glycolysis in cells with mitochondria and an adequate supply of oxygen?
Pyruvate
What is the significance of aerobic glycolysis?
It sets the stage for the oxidative decarboxylation of pyruvate to acetyl CoA
What is the result of deficiencies in enzymes of glycolysis?
Hemolytic anemias or fatigue
What is the relationship between glycolysis and other metabolic pathways?
Glycolysis provides intermediates for other metabolic pathways
What is the role of glycolysis in carbohydrate metabolism?
Glycolysis is the principal route for carbohydrate metabolism
What is the significance of the glycolytic pathway in skeletal muscle?
It allows skeletal muscle to perform at high levels of work output
What is the preparatory pathway for the aerobic metabolism of glucose?
Glycolysis
What is the primary function of anaerobic glycolysis in tissues?
To allow for the production of ATP in tissues that lack mitochondria or have insufficient oxygen
Which stage of glycolysis is characterized by the conversion of glucose to pyruvate?
All of the above
What is the ultimate fate of lactate produced in muscle tissue during intense exercise?
It is used by the liver to make glucose
What is the role of NADH in anaerobic glycolysis?
It is used to convert pyruvate to lactate
What is the significance of the glycolytic pathway in tissues that lack mitochondria?
It is the primary mechanism for ATP production in the absence of oxygen
Study Notes
Glycolysis
- The glycolytic pathway is used by all tissues to break down glucose and provide energy (in the form of ATP) and intermediates for other metabolic pathways.
- Glycolysis is the principal route for carbohydrate metabolism and can function without oxygen, making it important for high-intensity, short-duration activities like muscle contraction.
- Diseases resulting from deficient glycolysis enzymes are mainly seen as hemolytic anemias or muscle fatigue.
- Glucose enters cells through two transport mechanisms: Na+-independent, facilitated diffusion transport system and Na+-dependent monosaccharide cotransporter system.
Anaerobic and Aerobic Glycolysis
- In cells with mitochondria and adequate oxygen, pyruvate is the end product of glycolysis and is further oxidized to acetyl CoA, a major fuel of the TCA cycle.
- In the absence of oxygen, pyruvate is reduced to lactate, allowing ATP production in tissues without mitochondria (e.g., red blood cells) or with insufficient oxygen.
- Anaerobic glycolysis occurs in three stages: phosphorylation, splitting, and oxido-reduction.
Lactate Formation in Muscle
- In exercising skeletal muscle, NADH production is used to convert pyruvate to lactate due to inadequate oxygen supply.
- Lactate accumulation in muscle causes a drop in intracellular pH, potentially leading to cramps.
- Lactate can eventually diffuse into the bloodstream and be used by the liver to produce glucose.
Gluconeogenesis
- Gluconeogenesis is the de novo synthesis of glucose from lactate or other non-carbohydrate sources.
- The pathway of gluconeogenesis from lactate is a reversal of glycolysis, with the exception of a few reactions.
Glycolysis
- The glycolytic pathway is used by all tissues to break down glucose and provide energy (in the form of ATP) and intermediates for other metabolic pathways.
- Glycolysis is the principal route for carbohydrate metabolism and can function without oxygen, making it important for high-intensity, short-duration activities like muscle contraction.
- Diseases resulting from deficient glycolysis enzymes are mainly seen as hemolytic anemias or muscle fatigue.
- Glucose enters cells through two transport mechanisms: Na+-independent, facilitated diffusion transport system and Na+-dependent monosaccharide cotransporter system.
Anaerobic and Aerobic Glycolysis
- In cells with mitochondria and adequate oxygen, pyruvate is the end product of glycolysis and is further oxidized to acetyl CoA, a major fuel of the TCA cycle.
- In the absence of oxygen, pyruvate is reduced to lactate, allowing ATP production in tissues without mitochondria (e.g., red blood cells) or with insufficient oxygen.
- Anaerobic glycolysis occurs in three stages: phosphorylation, splitting, and oxido-reduction.
Lactate Formation in Muscle
- In exercising skeletal muscle, NADH production is used to convert pyruvate to lactate due to inadequate oxygen supply.
- Lactate accumulation in muscle causes a drop in intracellular pH, potentially leading to cramps.
- Lactate can eventually diffuse into the bloodstream and be used by the liver to produce glucose.
Gluconeogenesis
- Gluconeogenesis is the de novo synthesis of glucose from lactate or other non-carbohydrate sources.
- The pathway of gluconeogenesis from lactate is a reversal of glycolysis, with the exception of a few reactions.
Learn about the glycolytic pathway, its importance in providing energy and intermediates for metabolic pathways, and diseases related to deficient glycolysis enzymes.
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