Lecture 1 Pt 2 Flashcards
What does GAPDH do?
Leads to the reduction of NAD+ to NADH.
Glucokinase is activated
at high levels of glucose
GAP is oxidized/reduced
oxidized
NAD+ is oxidized/reduced
i
what are the 3 ways NADH, H is regenerated to NAD+
- Alcoholic fermentation
- Lactic fermentation
- Aerobic respiration (long, yields the most energy)
What is fermentation
ATP generating pathways in which electrons are removed from one organic compound and passed to another organic compound. Fermentation can take place in the absence of O2
how is NAD+ regenerated through lactic fermentation?
Pyruvate (lactic dehydrogenase and reproduces NADH), then produces 2ATP, 2 lactate
how is NAD+ regenerated through alcohol fermentation?
Pyruvate (pyruvate decarboxylase -> produce Co2) -> acetaldyhye -> (alcohol dehydrogenase -> regenerate NAD+) -> ethanol
Does alchol fermentation occur in humans?
No bc pyruvate carboxylase is not present in animal, requires thiamine
Where/what species does Lactic acid fermentation occur?
In muscles: lactice acid
microbes
soy sauce, cheese, youghrt
Where/what species does Alchocol fermentation occur?
yeast other microbes
bread beer wine
When can lactic acid build up?
Relate this to the glycolysis process
Skeletals, muscles, can only function anaerobically for a short period of time, which builds up lactate, lowers the pH and affects the PFK activity
Explain the Warburg effect
Cancer cells have increased metabolism.
After glycolysis is carried out, cells can undergo oxidative phosphorylation (which increases a high yield of enerngy), or fermentation (under no oxygen conditions, and provides lower energy).
Cancer cells have an increae uptake of glucose, and prefer going thorugh lactic fermentation (even in conditions where oxygen is present).
Cancer cells have a dependence for glucose higher than regular cells-> target for remediation
What kind of diet would you recommend to people wit
keto
Imaging question. What is the name of the molecule that can bind to glucose
FDG (a non-metabolasible glucose analog)
looks similar but does not undergo glycolysis.
glucose molecules csan bind to this. -> fluorescence -> acts as a sign to visualize uptake and see where tumors are localized.
What does a stronger FDG indicate
Those cells have a high intake of glucose
Does FDG undergo glycolysis?
No, it does not undergo full glycolsysi
How many carbons does lactose have? What does it break down to?
- Glucose and Galactose
How many carbons does sucrose have? What does it break down to?
- Glucose and fructose
Where does fructose come from?
Table sugar
Where does galactose come from
Milk
When does galactose enter the cell
at the glucose-6-p
When does fructose (adipose enter the cell)
at the fructose-6-P step (so theres still another ATP requiring step after to make fructose-6-P turn into frutose1,6 bisphosphate
When does fructose (liver, enter the cell)
at the DHAP <-> GAP step
In the liver, how is fructose metabolized?
The liver is a major site for fructose metabolism.
Fructose is metabolized by the fructose 1-phosphate pathway
In other tissues, how is fructose directly metabolised? How does fructose enter the pathway?
phosphorylzted by hexokinase -> enters as fructose-6-p
Does the metabolism of fructose in the liver still require ATP? How many ATP is yielded at the end of the process?
Yes Still requires the same investment of ATP. Cuz to convert fructose -> fructose -1 phosphate
Fructose-1-P -> GAP and DHAP.
Glyceraldehyde -> glyceraldyde 3 phosphate
2 ATP is still yielded at the end.
Glycolysis and fructolysis in the liver = equivalent in energy
For fructolysis in the liver. How many steps of glycolysis were bypassed? Were any of those regulatory steps?
2 steps:
Glucose -> glucose-6-P (hexokinase)
f-6-p -> f-1.6-p (phosphofructose kinase)
Some issues for fruclysis
Excess fructose consumption is harmful (its been linked to obesity, fatty liver and the development of type 2 diabetes) because in the liver, the PFK control point is bypassed -> excess.
So an excess of Acetyl CoA is synthesized and converted to fats
How does galactose enter the pathway?
galactose is converted to galactose-1-P via galactosekinase.
Galactose is gonna convert to Glucose-6-P with a galactose glucose interconversion pathway.
Enters pathway at glucose as glucose-6-P
What regulatory step does galactose bypass?
hexokinase
Why are red blood cells suceptible to deficiencies in glycolysis? What is the disease that it causes?
Mutation (reduction in gene), that encodes for pyruvate kinase -> causes a slow flux from phosphoenolpyruvate -> pyruvate.
causes hemolytic anemia
Why does lactose intolerance occur? What enzyme is lacking? what are the symptoms
Lactose interolent individuals lack the ability to break down lactose into glucose and galactose. lack the enzyme lactase.
Therefore gut bacteria in the stomach would break down lactose into CH4 and H2 -> make stomach upset
How does galactosemia occur? What enzyme is lacking? what are the symtoms?
Classic galactosemia results if galactose 1-phosphate uridyl transferase activity is deficient. Symptoms include failure to thrive, jaundice,. cataract formation.
What happens if glaactose-1_phosphate uridyl transferase activity is low?
its gonna be highly toixc for the body, build up, health problems, metabolise into otehr things.
Write the equation for alcohol fermentation
Write the equation for lactice acid fermentation
