p.5
Pentose Phosphate Pathway Functions
What is the pentose phosphate pathway?
A highly regulated metabolic pathway that is reversible and connects to glycolysis.
p.18
Blood Glucose Control and Insulin
What is a characteristic of insulin-independent pathways?
They allow glucose uptake without the need for insulin.
p.2
Carbohydrate Utilization in Energy Metabolism
What occurs during the postprandial phase of metabolism?
Glycogenolysis, gluconeogenesis, lipolysis, and deamination.
p.12
Regulation of Glycogenesis and Glycogenolysis
What activates glycogen phosphorylase?
Phosphorylation by phosphorylase kinase.
p.8
Carbohydrate Utilization in Energy Metabolism
Where is glucokinase primarily located?
In the liver and pancreas.
p.4
Pentose Phosphate Pathway Functions
What is the primary function of the Pentose Phosphate Pathway?
Reduction of NADP+ to NADPH.
p.9
Regulation of Glycogenesis and Glycogenolysis
What is the role of the branching enzyme in glycogenesis?
It facilitates the formation of glycogen branches.
p.11
Regulation of Glycogenesis and Glycogenolysis
What is glycogenolysis?
The process of breaking down glycogen into glucose.
p.14
Gluconeogenesis and Its Regulation
What are the key regulatory steps in gluconeogenesis?
The conversion of pyruvate to phosphoenolpyruvate, fructose-1,6-bisphosphate to fructose-6-phosphate, and glucose-6-phosphate to glucose.
p.3
Carbohydrate Utilization in Energy Metabolism
What is the primary function of carbohydrate metabolic pathways?
To convert carbohydrates into energy and other metabolites.
p.13
Regulation of Glycogenesis and Glycogenolysis
Which hormones stimulate glycogenolysis?
Glucagon and catecholamines.
p.18
Blood Glucose Control and Insulin
Can glucose metabolism occur without insulin?
Yes, through insulin-independent pathways.
p.2
Carbohydrate Utilization in Energy Metabolism
What is ketogenesis?
The process of producing ketone bodies from fatty acids.
p.12
Regulation of Glycogenesis and Glycogenolysis
What is the significance of glycogen phosphorylase regulation?
It controls the mobilization of glucose from glycogen stores.
p.16
Gluconeogenesis and Its Regulation
What are the key enzymes involved in converting pyruvate to phosphoenolpyruvate?
Pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK).
p.6
Regulation of Glycogenesis and Glycogenolysis
What is glycogen?
Glycogen is a polysaccharide that serves as a form of energy storage in animals.
p.14
Gluconeogenesis and Its Regulation
Where does gluconeogenesis primarily occur?
In the liver and to a lesser extent in the kidneys.
p.7
Regulation of Glycogenesis and Glycogenolysis
What role does adrenaline play in glycogenesis?
It inhibits glycogenesis.
p.12
Regulation of Glycogenesis and Glycogenolysis
How is glycogen phosphorylase regulated?
Through phosphorylation and dephosphorylation mechanisms.
p.8
Carbohydrate Utilization in Energy Metabolism
Where is hexokinase primarily located?
In muscle, brain, and adipose tissue.
p.16
Gluconeogenesis and Its Regulation
What activates fructose 1,6 bisphosphatase?
Glucocorticoids, glucagon, and citrate.
p.1
Glucose Synthesis from Non-Carbohydrate Sources
Why is glucose synthesis from non-carbohydrate sources important?
It helps maintain blood glucose levels during fasting or low carbohydrate intake.
p.4
Pentose Phosphate Pathway Functions
What is the secondary function of the Pentose Phosphate Pathway?
Creation of ribulose-5-phosphate, also known as pentose phosphates.
p.15
Gluconeogenesis and Its Regulation
What is a key feature of the regulation of glycolysis and gluconeogenesis?
There is variation in regulation between the two pathways.
p.18
Blood Glucose Control and Insulin
What are the two pathways of glucose metabolism mentioned?
Insulin-independent and insulin-dependent pathways.
p.17
Gluconeogenesis and Its Regulation
What is the malate shuttle's role in gluconeogenesis?
The malate shuttle helps transport reducing equivalents into the mitochondria for gluconeogenesis.
p.3
Metabolic Pathways: Glycolysis, TCA Cycle, and ETC
What role does the TCA Cycle play in carbohydrate metabolism?
It further oxidizes products of glycolysis to produce ATP and electron carriers.
p.13
Regulation of Glycogenesis and Glycogenolysis
How does muscle phosphorylase respond to AMP and ATP?
It is much more sensitive to AMP and less sensitive to ATP.
p.10
Regulation of Glycogenesis and Glycogenolysis
Why does glycogenolysis occur?
To release glucose for energy when blood sugar levels are low.
p.11
Regulation of Glycogenesis and Glycogenolysis
What role does the debranching enzyme play in glycogenolysis?
It helps to remove branches from glycogen, allowing for glucose release.
p.3
Metabolic Pathways: Glycolysis, TCA Cycle, and ETC
What are the main pathways involved in carbohydrate metabolism?
Glycolysis, TCA Cycle, and the Electron Transport Chain (ETC).
p.8
Carbohydrate Utilization in Energy Metabolism
What is the Km value characteristic of hexokinase?
Low Km; functions at maximum velocity at fasting blood glucose concentrations.
p.1
Glycemic Index and Health
What is the glycemic index?
A measure that indicates how foods affect blood glucose levels.
p.6
Regulation of Glycogenesis and Glycogenolysis
Where is glycogen stored?
In the liver and muscle tissues.
p.18
Blood Glucose Control and Insulin
What role does insulin play in glucose metabolism?
Insulin facilitates glucose uptake in insulin-dependent pathways.
p.2
Carbohydrate Utilization in Energy Metabolism
What are the main processes involved in carbohydrate metabolism?
Glycolysis, glycogenesis, TCA cycle, ETC, and lipogenesis.
p.12
Regulation of Glycogenesis and Glycogenolysis
What is the role of glycogen phosphorylase?
It is an enzyme that breaks down glycogen into glucose-1-phosphate.
p.8
Carbohydrate Utilization in Energy Metabolism
What is the Km value characteristic of glucokinase?
High Km; functions at maximum velocity only when glucose levels are high.
p.1
Carbohydrate Utilization in Energy Metabolism
What role does ATP play in carbohydrate utilization?
It serves as the energy currency in energy metabolism.
p.10
Regulation of Glycogenesis and Glycogenolysis
When does glycogenolysis occur?
During periods of fasting, exercise, or low carbohydrate intake.
p.2
Carbohydrate Utilization in Energy Metabolism
What metabolic processes occur during the fasting phase?
Ketogenesis, lipolysis, and proteolysis.
p.13
Regulation of Glycogenesis and Glycogenolysis
What is the effect of glucagon on glycogenolysis?
It stimulates glycogenolysis.
p.8
Regulation of Glycogenesis and Glycogenolysis
Is glucokinase inhibited by glucose-6-phosphate?
No, it is not inhibited by glucose-6-phosphate.
p.8
Blood Glucose Control and Insulin
How does insulin affect hexokinase in insulin-resistant individuals?
Not induced by insulin in insulin-resistant individuals.
p.1
Digestion and Absorption of Dietary Carbohydrates
What processes are involved in the digestion and absorption of dietary carbohydrates?
Digestion, absorption, transportation, and storage in the body.
p.15
Gluconeogenesis and Its Regulation
Is gluconeogenesis simply the opposite of glycolysis?
No, gluconeogenesis is not merely the opposite pathway of glycolysis.
p.17
Gluconeogenesis and Its Regulation
What is the role of PEP carboxykinase (PEPCK) in gluconeogenesis?
PEPCK catalyzes the conversion of oxaloacetate to phosphoenolpyruvate (PEP).
p.2
Carbohydrate Utilization in Energy Metabolism
What happens during starvation in terms of metabolism?
Increased reliance on ketogenesis and lipolysis for energy.
p.15
Gluconeogenesis and Its Regulation
What is gluconeogenesis?
A metabolic pathway that generates glucose from non-carbohydrate sources.
p.6
Regulation of Glycogenesis and Glycogenolysis
Why is glycogen important?
It provides a readily available source of energy when glucose levels are low.
p.14
Gluconeogenesis and Its Regulation
What are the main substrates for gluconeogenesis?
Lactate, glycerol, and amino acids (especially alanine).
p.7
Regulation of Glycogenesis and Glycogenolysis
How do calcium ions affect glycogenesis?
They inhibit glycogenesis.
p.12
Regulation of Glycogenesis and Glycogenolysis
What inhibits glycogen phosphorylase?
Dephosphorylation by protein phosphatase.
p.8
Regulation of Glycogenesis and Glycogenolysis
What inhibits hexokinase?
Allosterically inhibited by glucose-6-phosphate.
p.10
Regulation of Glycogenesis and Glycogenolysis
Where does glycogenolysis primarily occur?
In the liver and muscle tissues.
p.11
Regulation of Glycogenesis and Glycogenolysis
What is the function of glucose-6-phosphatase?
It converts glucose-6-phosphate into free glucose, allowing it to enter the bloodstream.
p.17
Gluconeogenesis and Its Regulation
What is the function of pyruvate carboxylase in gluconeogenesis?
Pyruvate carboxylase converts pyruvate into oxaloacetate.
p.3
Metabolic Pathways: Glycolysis, TCA Cycle, and ETC
What is glycolysis?
The process of breaking down glucose to produce energy.
p.13
Regulation of Glycogenesis and Glycogenolysis
Which molecules inhibit glycogenolysis?
ATP, glucose-6-phosphate, and caffeine.
p.16
Gluconeogenesis and Its Regulation
What is the role of fructose 1,6 bisphosphatase in gluconeogenesis?
It converts fructose 1,6 bisphosphate to fructose 6-phosphate.
p.1
Metabolic Pathways: Glycolysis, TCA Cycle, and ETC
What are the relationships among glycolysis, the TCA cycle, and the electron transport chain?
They are interconnected pathways involved in cellular respiration and energy production.
p.6
Regulation of Glycogenesis and Glycogenolysis
When does glycogenesis occur?
It occurs when there is an excess of glucose in the bloodstream.
p.14
Gluconeogenesis and Its Regulation
What is gluconeogenesis?
It is the metabolic process of synthesizing glucose from non-carbohydrate sources.
p.7
Regulation of Glycogenesis and Glycogenolysis
What inhibits glycogenesis?
Glycogen, adrenaline, calcium ions, and ADP.
p.3
Metabolic Pathways: Glycolysis, TCA Cycle, and ETC
How does the Electron Transport Chain (ETC) contribute to energy production?
By using electrons from NADH and FADH2 to generate ATP through oxidative phosphorylation.
p.13
Regulation of Glycogenesis and Glycogenolysis
How does liver phosphorylase differ in sensitivity compared to muscle phosphorylase?
Liver phosphorylase is less sensitive to AMP, ATP, and glucose-6-phosphate.
p.16
Gluconeogenesis and Its Regulation
What inhibits fructose 1,6 bisphosphatase?
Fructose 2,6-bisphosphate (F-2,6-BP), AMP, and insulin.
p.1
Blood Glucose Control and Insulin
How is blood glucose metabolically controlled?
Through various metabolic pathways and the role of insulin.
p.8
Blood Glucose Control and Insulin
Is hexokinase induced by insulin in normal individuals?
No, it is not induced by insulin in normal individuals.
p.8
Blood Glucose Control and Insulin
Is glucokinase induced by insulin in normal individuals?
Yes, it is induced by insulin in normal individuals.
p.1
Carbohydrate Classes and Features
What are the main carbohydrate classes characterized by?
Their structural and functional features.
p.8
Blood Glucose Control and Insulin
How does insulin affect glucokinase in insulin-resistant individuals?
Not induced by insulin in insulin-resistant individuals.
