Carbohydrates Part 2 Flashcards
What level energy requirements does the neural retina require? How does the aerobic glucose consumption compare to other tissues?
High energy requirements
Highest aerobic glucose consumption
In what ways does the retina use glucose?
Aerobically and anaerobically
Describe the pathway of aerobic glycolysis. Is this more or less common compared to anaerobic?
NADH is oxidized to NAD+
Glucose converted to pyruvate
TCA
Oxidative phosphorylation
*This is the typical pathway of glucose
What pathway follows anaerobic glycolysis.
Followed by lactate fermentation (glucose is converted to lactate)
What is the Warburg effect? What kind of cells is it observed in?
Increase in rate of glucose uptake, lactate production is preferred even when oxygen is present
Observed in rapidly dividing cancer cells
What is the predominant cells in the retina that have high glucose needs?
Photoreceptors (rods)
What does NADPH function as? In what process is it required?
H+ donor
Required to produce ATP
What process is necessary for photoreceptor cell survival? What occurs when this pathway is impaired? Upregulated?
Glycolysis
Retinal degeneration
Neuroprotection
For what processes do photoreceptors require copious amounts of NADPH?
Did membrane biogenesis
Antioxidant metabolism
Reduction of all trans-retinal
Detoxifies the retina
What is aerobic glycolysis necessary for? What does it prevent?
For normal rod function
Prevent cone degeneration in retinitis pigmentosa
How do rod and cone photoreceptor cells (PRs) interact with the RPE and muller cells? What does PR deliver to them?
PRs are in close contact with RPE and muller
PRs deliver lactate
A metabolic ecosystem exists between them
Where does cellular respiration occur?
Cytosol and mitochondria
How many pyruvate are synthesized from one glucose molecule during glycolysis?
2
Describe glycolysis. Does it require oxygen? What does it release? Where does it occur?
Breakdown of glucose by enzymes
Releases energy and pyruvate
Does not require oxygen
Occurs in the cytosol/ cytoplasm (part of the cytoplasm = cytosol + organelle
What is the free energy from glycolysis used to form?
ATP and NADH (used to make ATP)