How many carbons does pyruvate have?
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3 carbons.
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How many carbons does pyruvate have?
3 carbons.
Where is glucokinase primarily found?
In the liver, kidney, and β cells.
What process is associated with Gibbs change in free energy?
Cellular respiration.
What is the primary function of digestion in relation to carbohydrates?
To break down carbohydrates into simpler sugars for absorption.
What enzyme catalyzes the conversion of Fructose-6-phosphate to Fructose-1,6-bisphosphate?
Phosphofructokinase.
How many additional ATP molecules are produced per glucose molecule by the oxidation of acetyl-CoA in the TCA cycle?
20 molecules of ATP.
What is the role of ATP in substrate level phosphorylation?
ATP is produced from ADP during the conversion of phosphoenolpyruvate to pyruvate.
What is produced at the end of glycolysis?
Pyruvate.
What type of process is glycolysis?
Anaerobic process.
What does Gibbs change in free energy (ΔG) represent?
The portion of the total energy change in a system that is available for doing work.
What is the purpose of the shuttle mechanism in glycolysis?
To transport reducing equivalents from NADH into mitochondria for oxidation.
What is the substrate that is converted to Fructose-1,6-bisphosphate in the phosphorylation step?
Fructose-6-phosphate.
What is pyruvate converted to in the mitochondria for the TCA cycle?
Acetyl-CoA.
What are the main enzymes involved in carbohydrate digestion?
Amylase and maltase.
Is glucokinase inhibited by glucose-6-phosphate?
No, it is not inhibited by G-6-P.
How many carbons does glucose have?
6 carbons.
Why can't NADH cross the mitochondrial membrane?
Because it is a charged molecule.
What is the substrate level phosphorylation step in glycolysis?
Conversion of phosphoenolpyruvate to pyruvate.
Which enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate?
Pyruvate Kinase.
What happens to NADH formed in glycolysis?
It is taken up into mitochondria for oxidation via shuttle mechanisms.
What is glycolysis?
The metabolic pathway that converts glucose into pyruvate, producing ATP and NADH.
What are the substrates involved in the phosphorylation of glucose?
ATP and glucose.
What is produced when ATP is used in the phosphorylation of Fructose-6-phosphate?
Fructose-1,6-bisphosphate.
What is the substrate that is converted to Phosphoenolpyruvate in this step?
2-Phosphoglycerate.
What happens to pyruvate in aerobic conditions?
It goes to the Krebs cycle and electron transport chain (ETC) in the presence of O2.
What enzyme facilitates the isomerization in STEP 5?
Triose Phosphate Isomerase.
What is the Km value for glucokinase?
Approximately 10 mM.
What is the role of Triose Phosphate Isomerase?
It interconverts Dihydroxyacetone phosphate and Glyceraldehyde-3-phosphate.
What is produced when glucose is phosphorylated?
Glucose-6-phosphate.
What is the enzyme involved in the conversion of 3-Phosphoglycerate to 2-Phosphoglycerate?
Phosphoglycerate Mutase.
What is removed during the dehydration step of glycolysis?
Water (H2O).
What are metabolic pathways?
Series of chemical reactions in a cell that lead to the conversion of substrates into products.
How does hexokinase operate under normal conditions?
It is saturated and acts at a constant rate.
What determines whether glycolysis should move forward in muscle cells?
The ATP:AMP ratio.
What is a catabolic pathway?
A metabolic pathway that breaks down molecules to produce energy.
What is aerobic glycolysis?
A metabolic process that converts glucose into pyruvate in the presence of oxygen.
What is the role of oxygen in aerobic glycolysis?
Oxygen is required for the complete oxidation of pyruvate in the mitochondria.
What is the final product of glycolysis?
Two molecules of pyruvate are produced from one molecule of glucose.
What is the process of converting glucose-6-phosphate to fructose-6-phosphate called?
Isomerization.
Where is hexokinase found?
In all tissues.
What enzyme is responsible for the phosphorylation of glucose?
Hexokinase.
What is the primary substrate for glycolysis?
Glucose.
What is the end product of glycolysis?
Pyruvate.
What are the energy molecules involved in the phosphorylation step?
ATP and ADP.
Is hexokinase inhibited by glucose-6-phosphate?
Yes, it is inhibited by G-6-P.
What are the two forms of Phosphoglycerate mentioned?
3-Phosphoglycerate and 2-Phosphoglycerate.
How many molecules of NADH are produced in this step?
2 molecules of NADH.
How are metabolic pathways categorized?
They can be categorized into catabolic and anabolic pathways.
What role does the liver play in glucose metabolism?
It uses molecules from glycolysis for biosynthetic/metabolic reactions.
What are the main products of carbohydrate metabolism?
Glucose, ATP, and other metabolites.
What happens to pyruvate in the presence of oxygen?
It enters the citric acid cycle for further energy production.
What happens to glucose-6-phosphate in glycolysis?
It is isomerized to fructose-6-phosphate by the enzyme phosphoglucose isomerase.
What are the two key molecules involved in STEP 5?
Dihydroxyacetone Phosphate and Glyceraldehyde-3-Phosphate.
What is the first step in the glycolysis process?
Phosphorylation.
What is the Km value for hexokinase?
Approximately 0.1 mM.
What is the main substrate involved in substrate-level phosphorylation in this step?
1,3-Bisphosphoglycerate.
Which enzyme catalyzes the dehydration of 2-Phosphoglycerate?
Enolase.
What enzyme is involved in the oxidation of Glyceraldehyde-3-Phosphate?
Glyceraldehyde-3-Phosphate dehydrogenase.
What are the reactants in the substrate-level phosphorylation process described?
1,3-Bisphosphoglycerate and ADP.
What is glycogenolysis?
The breakdown of glycogen into glucose-1-phosphate and glucose.
How are monosaccharides absorbed in the intestine?
Through active transport and facilitated diffusion.
What is another shuttle system used for re-oxidizing NADH?
Glycerol-3-phosphate Shuttle.
What does the liver do when glucose levels are high?
Stores glucose as glycogen.
How many ATP molecules are produced in glycolysis?
A net gain of 2 ATP molecules per glucose molecule.
What happens to pyruvate after aerobic glycolysis?
It enters the citric acid cycle (Krebs cycle) for further energy production.
What is the role of phosphofructokinase in glycolysis?
It phosphorylates fructose-6-phosphate to fructose-1,6-bisphosphate, a key regulatory step.
What is the process described in STEP 5?
Isomerization.
Which enzyme catalyzes the conversion of glucose-6-phosphate to fructose-6-phosphate?
Phosphoglucoisomerase.
What are reducing equivalents?
Electrons or hydrogen ions that can be transferred in redox reactions.
What are the major pathways of carbohydrate metabolism?
Glycolysis, gluconeogenesis, glycogenolysis, and glycogenesis.
What are the products of the reaction catalyzed by pyruvate kinase?
Pyruvate, ATP, and ADP.
What are some polysaccharides involved in energy storage?
Glycogen, starch, and sucrose.
How many ATP molecules are produced in glycolysis?
A net gain of 2 ATP molecules.
What is the end product of carbohydrate digestion?
Monosaccharides, primarily glucose.
What is the significance of metabolic pathways?
They are essential for energy production, biosynthesis, and regulation of cellular processes.
What is one function of glycolysis besides energy production?
Synthesis of structural polymers.
What do 2 ADP molecules combine to form?
1 ATP and 1 AMP.
What are the end products of glycolysis?
Pyruvate, ATP, and NADH.
What is the net ATP yield from one molecule of glucose during aerobic glycolysis?
2 ATP molecules are produced directly from glycolysis, but more ATP is generated in subsequent steps.
What is the role of NAD+ in glycolysis?
NAD+ is reduced to NADH during the oxidation of glyceraldehyde-3-phosphate.
What is glycolysis?
The sweet breakdown or split of glucose.
What is another term for the useful energy in a system?
Chemical potential.
What are the two forms of phosphate involved in the isomerization step?
Glucose-6-phosphate and fructose-6-phosphate.
What is the primary purpose of glycolysis?
ATP production.
What is produced from Glyceraldehyde-3-Phosphate during oxidation?
1,3-Bisphosphoglycerate.
What is fructose metabolism?
The process by which the body breaks down fructose, a simple sugar found in many plants.
Where does carbohydrate digestion begin?
In the mouth with salivary amylase.
What is the role of NAD+ in the oxidation step?
It is reduced to NADH + H+.
What is a key enzyme involved in fructose metabolism?
Fructokinase, which phosphorylates fructose to fructose-1-phosphate.
What is the initial substrate for glycolysis?
Glucose.
What role does the extracellular matrix play in relation to glycolysis?
It is involved in the structure and support of cells, but not directly in glycolysis.
What is glycolysis?
A metabolic pathway that converts glucose into pyruvate, producing ATP and NADH.
What role does NADH play in glycolysis?
It acts as an electron carrier, facilitating the transfer of electrons during the process.
What is the significance of 1,3-bisphosphoglycerate?
It is converted to 3-phosphoglycerate, producing ATP in the process.
What happens to pyruvate in anaerobic conditions?
It goes through the lactic acid cycle to become lactate in the absence of O2.
What is the product of splitting Fructose-1,6-phosphate?
Dihydroxyacetone phosphate and Glyceraldehyde-3-phosphate.
Which enzyme is responsible for the cleavage of Fructose-1,6-phosphate?
Aldolase.
What is the product of the dehydration step in glycolysis?
Phosphoenolpyruvate (PEP).
How does glucokinase respond to blood glucose levels after a meal?
It removes glucose from the blood.
What enzyme is responsible for the conversion of 1,3-Bisphosphoglycerate to ATP?
Phosphoglycerate Kinase.
What is gluconeogenesis?
The process of synthesizing glucose from non-carbohydrate precursors.
What happens to the 2 NADH produced by glycolysis under aerobic conditions?
They may be effectively re-oxidized by the mitochondria through a shuttle system.
What are the products of the substrate-level phosphorylation in this step?
ATP.
What is the primary pathway for galactose metabolism?
The Leloir pathway, which converts galactose to glucose-1-phosphate.
What condition is associated with galactose metabolism disorders?
Galactosemia, which can cause serious health issues if not managed.
What is the primary focus of carbohydrate metabolism?
The breakdown and utilization of carbohydrates for energy.
What is glycolysis?
The metabolic pathway that converts glucose into pyruvate, producing ATP.
How many ATP molecules are generated in glycolysis?
A net gain of 2 ATP molecules is produced per glucose molecule.
What is galactose metabolism?
The biochemical pathway that converts galactose into glucose and other metabolites.
What is the byproduct of the phosphorylation reaction?
ADP.
What pathway is involved in the oxidation of ribose-5-phosphate?
Pentose phosphate pathway.
What is added to Glyceraldehyde-3-Phosphate during the oxidation process?
Inorganic phosphate.
What is an anabolic pathway?
A metabolic pathway that builds complex molecules from simpler ones, requiring energy.
What is the primary product of aerobic glycolysis?
Pyruvate.
Is glycolysis an aerobic or anaerobic process?
Glycolysis is an anaerobic process, occurring without oxygen.
What is the first step of glycolysis?
Glucose is phosphorylated to glucose-6-phosphate by the enzyme hexokinase.
What is one of the shuttle systems used for re-oxidizing NADH?
Malate-Aspartate Shuttle.
What can excessive fructose consumption lead to?
Metabolic disorders such as insulin resistance and fatty liver disease.
What does the liver do when glucose levels are low?
Releases glucose.
How does aerobic glycolysis differ from anaerobic glycolysis?
Aerobic glycolysis occurs in the presence of oxygen, while anaerobic glycolysis occurs without oxygen.
Where does glycolysis occur in the cell?
In the cytoplasm.
What is produced when fructose-1,6-bisphosphate is split?
It is split into two three-carbon molecules: dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.
overview of glycolysis products
What is glycogenesis?
The process of converting glucose into glycogen for storage.
What happens to glycolysis when the ATP:AMP ratio is low?
Glycolysis is activated.
How do liver isozymes affect glucose prioritization?
They allow glucose to be prioritized for the brain and muscles.
What role does insulin play in carbohydrate metabolism?
Insulin facilitates the uptake of glucose into cells.
What is the significance of the citric acid cycle?
It generates high-energy electron carriers for the electron transport chain.
What happens to glyceraldehyde-3-phosphate in glycolysis?
It is oxidized and phosphorylated to 1,3-bisphosphoglycerate by the enzyme glyceraldehyde-3-phosphate dehydrogenase.
