Review
Hydrogen bonds will NOT form between which of the following:
A. C-H and OH group
B. C=O and OH groups
C. Amines and C=O
D. Aldehydes and water
E. Alcohols and amines
A. C-H and OH group
Hydrogen bonding requires large differences in electronegativity between atoms, which does not occur in the C-H bond.
For a reaction S --> P the equilibrium concentrations are [S]=500mM and [P]=500mM. If Q=10 in the cell, which statement is true?
A. deltaG is positive.
B. At equilibrium there will be more products than substrates.
C. The reaction is favorable.
D. I need more information.
A. deltaG is positive.
Remember: deltaG = deltaG'0 +RTlnQ
Glucose acts as a sensor for glycogen degradation via a binding site on glycogen phosphorylase. Thus, glucose works as a
A. Heterotropic allosteric activator
B. Heterotropic allosteric inhibitor
C. Homotropic allosteric activator
D. Homotropic allosteric inhibitor
B. Heterotropic allosteric inhibitor
Which of the statements below is FALSE? Both lactate and ethanol fermentation...
A. use pyruvate as a substrate
B. regenerate NAD+
C. generate CO2
D. are anaerobic processes
E. yield reduced metabolites
C. generate CO2
Only ethanol fermentation yields CO2
Which of the following catalyzes NAD+ reduction in the TCA cycle?
a. Malate dehydrogenase
b. Citrate synthase
c. Pyruvate dehydrogenase complex
d. Succinate dehydrogenase
e. Lactate dehydrogenase
a. Malate dehydrogenase
What is the fold difference in [H+] between pH 5 and pH 7?
100 fold
Remember: pH = -log[H+]
In order for deltaG to be zero, the concentration of products and substrates
A. Must be the same ratio as they are at equilibrium.
B. Must be equal to each other.
C. Must equal zero.
D. I need more information.
B. Must be equal to each other.
Remember:
deltaG = deltaG'0 + RTlnQ
Glycogen phosphorylase is active…
a. in skeletal muscle
b. only where Glucose-6-Phosphatase is active
d. everywhere except the brain
e. in the muscle and liver
e. in the muscle and liver
Which enzymes initiate 1) the preparatory and 2) the payoff phases of glycolysis?
Hexokinase and GAPDH
(Also remember: Which step is the commitment step to glycolysis?)
Pyruvate generated from glycolysis reacts with _____________ before entering the TCA cycle.
A. Acetyl CoA
B. Citrate
C. Oxaloacetate
D. HSCoA
D. HSCoA
Name two amino acids that you would expect to see in porin proteins, but not the GLUT4 transporter.
Proline and glycine. Porin proteins are composed of beta barrels and glut4 is predominantly composed of alpha helices.
Name two ways that reactions with an unfavorable standard state deltaG can proceed in the cell.
Glycogen synthase...
a. creates alpha 1,4 glycosidic linkages using G-6-P and glycogen as precursors
b. liberates UTP and creates Glycogenn+1
c. liberates Pi and creates Glycogenn+1
d. Is active when Glycogen phosphorylase is phosphorylated.
a. creates alpha 1,4 glycosidic linkages using G-6-P and glycogen as precursors
Which type of enzymes are used in gluconeogenesis to obtain product form the irreversible steps 1 and 3?
What do they do?
How do they differ from their glycolytic counterparts?
Phosphatases
Remove phosphate groups from metabolites
Do not use or produce ATP!
How many CO2 are generated in one cycle of the immediate TCA cycle?
Two! (one for each carbon going into the cycle)
The Bohr Effect directly explains how/why …
A. Myoglobin and hemoglobin are located in distinct tissues.
B. Carbon monoxide has a very high affinity for the heme group of myoglobin and hemoglobin.
C. It is difficult to run at high elevations until the body has acclimated for several days.
D. Products of respiration allow for increased oxygen release in the muscle.
E. As pH increases, hemoglobin binds less tightly to oxygen.
D. Products of respiration allow for increased oxygen release in the muscle.
CO2 release induces higher levels of carbonic acid. The decrease in pH leads a decrease in affinity of oxygen to hemoglobin in the muscle.
What is the net energetic result of unregulated glycolysis and gluconeogenesis in the cell?
The hydrolysis of 4 ATP
Usage in Gluconeogenesis:
Pyruvate carboxylase (2)
PEP carboxykinase (2)
Phosphoglycerate kinase (2)
Fill in the associate products for the following reaction:
Glycogenn + _______ --> Glycogenn+1 + _________
Glycogenn + UDP-glucose --> Glycogenn+1 + UDP
Which of the following is true of the fermentation process?
A. Lactate in the liver builds up in order to regenerate NAD+ for use in the muscle.
B. The Cori cycle ensures that pyruvate -->lactate has a deltaG < 0 during strenuous exercise.
C. Pyruvate in the liver will get shipped to the muscle in order to keep [S]>[P] and deltaG<0.
D. Lactate fermentation occurs so that NADH is continually available for the GAPDH reaction.
B. The Cori cycle ensures that pyruvate -->lactate has a deltaG < 0 during strenuous exercise.
What is the yield for the degradation of 1 glucose molecule through the TCA cycle?
____ ATP/GTP
____ FADH2
____ NADH + H+
2 ATP (Succinyl CoA Synthetase)
2 FADH2 (Succinate DH)
6 NADH + H+ (IDH, alphaKGDH, MDH)