Download Unit One: Introduction to Physiology: The Cell and General

Chapter 67: Metabolism of Carbohydrates, and Formation
of ATP
Guyton and Hall, Textbook of Medical Physiology, 12th edition
Metabolism of Carbohydrates
• Release of Energy from Foods and the Concept of
“Free Energy”
a. Coupled reactions
b. Free energy
c. ATP as the energy currency of the cell
Metabolism of Carbohydrates
• Release of Energy from Foods and the Concept of
“Free Energy”
Fig. 67.1
Metabolism of Carbohydrates
• Release of Energy from Foods and the Concept of
“Free Energy”
Fig. 67.2
Metabolism of Carbohydrates
• Central Role of Glucose in Cbh Metabolism
Metabolism of Carbohydrates
•Transport of Glucose Through the Cell Membrane
a.
b.
c.
d.
Via facilitated diffusion
Active sodium-glucose co-transport
Insulin increases the facilitated diffusion of glucose
Immediate phosphorylation upon entry into cell
to form glucose-6-phosphate
e. Can be used immediately or stored as glycogen in
the liver and skeletal muscle
Metabolism of Carbohydrates
• Glycogenesis-the Formation of Glycogen
• Glycogenolysis-the Breakdown of Stored Glycogen
Fig. 67.4
Metabolism of Carbohydrates
• Release of Energy from Glucose by the Glycolytic
Pathway
Fig. 67.5 Glycolysis
Metabolism of Carbohydrates
• Conversion of Pyruvic Acid to Acetyl CoA
•
Citric Acid Cycle
Fig. 67.6
Metabolism of Carbohydrates
• Formation of Large Quantities of ATP by Oxidation
of Hydrogen-the Process of Oxidative
Phosphorylation
Fig. 67.7
Metabolism of Carbohydrates
• Formation of Large Quantities of ATP by Oxidation
of Hydrogen-the Process of Oxidative
Phosphorylation
a. Chemiosmotic mechanism of the mitochondria to
form ATP
b. Pumping of hydrogen ions into the outer chamber of
the mitochondria, caused by the electron transport
chain
c. Formation of ATP
Metabolism of Carbohydrates
• Energy Summary
a. During glycolysis, 4 ATPs are produced but a net
gain of only 2 ATPs (two are needed to start the
process); also generate 2 NADHs
b. During the transition rx, 2 NADHs are formed
c. During each revolution of the citric acid cycle, one
ATP, 3 NADH, 1 FADH2
d. Generate a total of 38 ATP (3 per each NADH and
2 per each FADH2)
Metabolism of Carbohydrates
• Anaerobic Release of Energy (Fermentation)
a. Formation of lactic acid
b. Reconversion of lactic acid to pyruvic acid when
oxygen becomes available again
Metabolism of Carbohydrates
• Release of Energy from Glucose by the Pentose
Phosphate Pathway
Fig. 67.8
Metabolism of Carbohydrates
• Gluconeogenesis- formation of carbohydrates from
proteins and fats
a. Regulation of gluconeogenesis
b. Effect of corticotropin and glucocorticoids
c. Blood glucose