Flashcards in Carbohydrate Metabolism-Glycolysis Deck (21)
List common monosaccarides
fructose, galactose, glucose
Can glucose cross the plasma membrane?
No; glucose is a very important molecule, but can't cross the membrane readily so it needs to cross via GLUT transporter via facilitated diffusion.
Tell me what cells have GLUT1 transporter
brain, cornea (so easy to get cataracts), erythrocytes(only source of energy)
Tell me what cell have GLUT 2 Transporter
main transporter of LIVER and PANCREAS
Tell me what cell have GLUT3 Transporter
Tell me what cells have GLUT 4 Transporter
Heart Cells, Adipose Cells, Skeletal Muscle Cells
Where is GLUT4 found? What is its use?
GLUT4 Transporter is used in skeletal, cardiac, and adipose cells. GLUT4 Transporters are found in vesicles pre-made to respond to insulin receptors for the fusion and release into the plasma membrane.
What is the net result of glycolysis?
2 pyruvate molecules, 2 NET ATP, 2 NADH Molecules
What is the difference between hexokinase and glucokinase?
Hexokinase has lower kM and has greater affinity for glucose; found in all cells
Glucokinase has higher kM and is found in specifically liver and pancreatic cells. These cells have a MACROFUNCTION for regulating glucose. They are the LAST to uptake glucose after the whole body has finished.
What is the rate limiting step of glycolysis?
Which enzymes are the rate-limiting enzymes for glycolysis?
The rate-limiting enzymes are conrolled by which by-products?
ATP, AMP, INSULIN, GLUCOSE, GLUCAGON
Why is glucokinase weakly inhibited by G6P, but hexokinase is strongly inhibited by G6P?
Glucokinase has a WEAK AFFINITY to GLUCOSE in the first place anyway! So, it makes sense that Glucokinase would weakly be allosterically inhibited by G6P.
Is PFK-1 activated or de-activated by phosphorylation?
PFK-1 is deactivated by phosphorylation and ACTIVATED by dephosphorylation.
What allosterically inhibits/ activates PFK-1?
Allosterically Activates: F2,6,BP; AMP
Allosterically Inhibits: ATP; Citrate
So, according to the logic of PFK-1, would it be plausible to say that PFK-2 is also activated by dephosphorylation (specifically by protein phosphatase enzyme)?
Yes; PFk-2 is ALSO activated by dephosphorylation.
What are the many different metabolic fats of G6P?
-Glycolysis, Pentose Phosphate Pathway, Glycogenesis, gluconeogenesis
What would a disorder in the glycolitic pathway cause?
IT WOULD CAUSE IN ALMOST ALL DISORDERS; HEMOLYTIC ANEMIA BECAUSE ERYTHROCYTES USE GLYCOLYSIS TO CREATE ENERGY.
What is Type 1 Diabetes caused by?
Loss of Pancreatic Beta Cells
What is Type 2 Diabetes caused by?
insulin resistance; loss of Beta Cell Functionality