Exam 3 – Dr. Sullivant Carbohydrate Metabolism Flashcards
What are the body’s energy sources?
Food intake (CHOs, fats, proteins)
Metabolism
ATP
Why is metabolism important?
All cells and tissues must have energy for survival/homeostasis, growth, reproduction, repair, and movement
What is the main energy source used by the body?
ATP
Where is ATP present?
In cytoplasm and nucleoplasm of all cells
What is ATP a combination of?
Adenine
Ribose
3 phosphate radicals
What is ATP obtained from?
CHO, proteins, and fats
Where does the important stuff/magic happen in ATP?
In phosphate radicals
What does the breaking of a phosphate molecule from ATP do?
Causes a band of energy release, which powers muslce
Why does ATP provide so much energy?
High energy bonds
Removal of each of the last 2 phosphate radicals liberates 12,000 calories of energy
ATP is involved in energy utilization. What does it do?
Active ion transport
Muscle contraction
Synthesis of molecules
Cell division and growth
ADP and Pi are involved in energy production. What do they do?
Help proteins, CHOs, and fats that are involved in oxidation
What do kinases do?
Add a phosphate
What do phosphatases do?
Remove a phosphate
What does phosphorylase do?
Splits a compound by adding phosphate
What are 90% of CHOs in the body used for?
ATP production
What are the final products of CHO digestion in the gut?
Fructose
Galactose
Glucose (80%)
What happens after fructose and galactose absorption from the GI tract?
They are rapidly converted to glucose in the liver via glucose phosphatases; therefore, glucose is the final common pathway for transport/supply of CHO to all tissues
What is option 1 for the fate of glucose in the liver?
CHO is processed in the liver, then glucose formation, then transport out of liver to needy tissues for energy use
- Glucose has to go through a cell membrane
- Glucose foes through a series of reactions inside the cell to produce ATP (glycolysis, TCA)
- Hydrogen atoms that are released concurrently yield even more ATP (glycolysis, TCA)
What is option 2 for the fate of glucose in the liver?
CHO processed in the liver, then glucose formation, the glycogenesis (energy storage)
What is glycogen?
A large polymer of glucose
What is option 3 for the fate of glucose in the liver?
Glycogenolysis in the liver
What is glycogenolysis?
Breakdown of stored glycogen in times of energy needs
What produces ATP?
Glucose entry into the cell Glycolysis Citric acid cycle Chemiosmotic mechanism Pentose phosphate pathway Glycogenesis Glycogenolysis
Glucose is too large to pass through cell membranes. What allows it pass?
Facilitated diffusion