WEEK 1 (Glycolysis) Flashcards
What is Glucose converted into via Anaerobic Metabolism?
Lactate
What is Glucose converted into via the TCA cycle?
H2O and CO2
What is Glucose converted into via the HMP Shunt?
Ribose and NADPH
What is Glucose converted into via Fatty Acid synthesis pathway?
Fatty Acids
What is Glucose converted into via Glycogenesis?
Glycogen
What are the two types of Glucose entry into cells?
Na+ independent entry and Na+ dependent entry
What is the difference between Na+ independent entry and Na+ dependent entry?
Na+ independent entry:
- 14 different transporters
- Varies by tissue
Na+ dependent entry:
- Glucose is absorbed from low to high concentration
- Occurs in Intestinal epithelium in Renal tubules
What are Sodium-dependent glucose cotransporters?
A family of glucose transporters found in the INTESTINAL MUCOSA of the SMALL INTESTINE and the PROXIMAL TUBULE of the NEPHRON
Describe how Sodium-dependent glucose co-transporters work
An Na+/K+ ATPase pump pumps 3 sodium ions OUTWARD into the blood while BRINGING IN 2 potassium ions which creates a downhill SODIUM ION GRADIENT from the outside to the inside of the proximal tubule cell. The SGLT proteins use the energy from the sodium ion gradient created by ATPase pump to transport glucose across the APICAL MEMBRANE, against an uphill glucose gradient.
What are GLUT 1, GLUT 2, GLUT 3 & GLUT 4?
Na+ independent transporters
Describe GLUT 1
- Found in most tissues (brain, red blood cells)
- 1mM (low Km suggests high affinity so glucose uptake from bloodstream is constant)
- MAIN FUNCTION: Basal uptake of glucose
What does Km mean?
The Km value is an indicator of the affinity of the transporter protein for glucose molecules so a low Km suggests a high affinity
(therefore GLUT1 and GLUT3 have a high affinity for glucose and uptake from the bloodstream is constant)
Describe GLUT 2
- Found in Liver and Pancreatic B-cells
- 15 mM (high Km allows for glucose sensing)
- MAIN FUNCTION: Uptake and release of glucose by the liver B-cell glucose sensor
Describe GLUT 3
- Found in most tissues
- 1 mM (low Km suggests high affinity so glucose uptake from bloodstream is constant)
- MAIN FUNCTION: Basal uptake of glucose
GLUT 4
- Found in skeletal muscle and adipose tissue
- 5mM
- MAIN FUNCTION: Insulin-stimulated glucose uptake and stimulated by exercise in skeletal muscle
What is Glycolysis also called?
Embden-Meyerhof Pathway (EMP)
What happens in Glycolysis?
One molecule of glucose (6 carbon molecule) is degraded into two molecules of pyruvate (3 carbon molecule) & Free energy is released and is stored as 2 molecules of ATP and 2 molecules of NADH