Carbohydrate Metabolism Flashcards
What about the pentose phosphate pathway makes it unique?
It does not require or generate any energy
What is the key product generated in the oxidative phase of the PPP?
NADPH - the electron donor
What is the key product generated in the non-oxidative phase of the PPP?
Ribose 5 phosphate (for DNA/RNA building)
The investment stage of glycolysis uses [……] to break glucose down into […] [….] molecules.
uses 2 ATP; breaks glucose down into 2 3-carbon molecules.
What do each of the 3 carbon molecules become? What is the ATP amount per 3 carbon molecule?
The 2 3-carbon molecules become 2 pyruvate which generates 2 ATP per pyruvate
List the three unique rxns of gluconeogenesis?
- pyruvate to PEP via oxaloacetate (intermediate)
- fruc. 1,6 BP to fruc. 6 BP via fruc. 1,6 BPase
- glucose 6 phos. to glucose via glucose 6 phosphatase
Describe a macro application of le chatlier’s principle in the context of glycolysis/gluconeogenesis regulation
Insulin and glucagon. A rise in glucose releases insulin to break down glucose but when glucose levels get too low in the body, that halts glycolysis and triggers the release of glucagon to raise glucose levels in the body.
How does allosteric product inhibition take place within glycolysis/gluconeogenesis regulation?
ATP (a product of glycolysis) inhibits glycolysis upon buildup.
AMP (a product of gluconeogenesis) inhibits gluconeogenesis upon buildip.
What carbohydrates are reactants in glycolysis?
A. glucose and fructose
B. glucose only
C. sucrose
D. none of these
Glucose only
In which organisms does glycolysis occur?
A. only anaerobic
B. both anaerobic and aerobic
C. only aerobic
Both anaerobic and aerobic organisms. AFTER glycolysis is when nrg. production is dependent on environmental factors like presence of O2
Which statement concerning the glycolytic and gluconeogenic pathways is correct?
A. gluconeogenesis is anabolic and glycolysis is catabolic.
B. Gluconeogenesis and glycolysis are identical pathways.
C. Glycolysis occurs due to a lack of glucose and gluconeogenesis occurs due to having too much glucose.
A. gluconeogenesis is anabolic and glycolysis is catabolic
What body conditions favor gluconeogenesis over glycolysis?
A. Starvation
B. Fullness
C. Stress
starvation
In the redox reaction: pyruvate + NADH + H+ ⇋ lactate + NAD+, which reactant is oxidized, and which is reduced?
Pyruvate is being reduced and NADH is being oxidized
What important reducing agent is an important product of the pentose phosphate pathway?
NADPH the electron donor
What is the best description for the energetics of glycolysis?
A. glycolysis always has a negative free nrg. so therefore every single step of the mechanism is energetically favorable.
B. Overall, under typical cellular conditions, glycolysis has a negative free-energy change, though there are steps of both positive and negative free-energy change
C. glycolysis has a positve gibbs free energy value but has to be coupled to energetically favorable rxns to bring the total free energy down to an exergonic level.
B.
