The standard free energy ($\Delta G'$) values of reactions catalyzed by citrate lyase and citrate synthetase are -670 and -8192 cal/mol, respectively.
$\Delta G_1' = -670$ cal/mole
$\Delta G_2' = -8192$ cal/mole
The standard free energy (in cal/mol) of acetyl-CoA hydrolysis is ____ (correct to integer number).
Step 1: Given reactions
Reaction 1 (citrate lyase):
$\text{Citrate} \rightarrow \text{Acetate} + \text{Oxaloacetate}$
$\Delta G'_1 = -670 \text{ cal/mol}$
Reaction 2 (citrate synthetase):
$\text{Acetyl-CoA} + \text{Oxaloacetate} + H_2O \rightarrow \text{Citrate} + \text{CoA}$
$\Delta G'_2 = -8192 \text{ cal/mol}$
Step 2: Add the two reactions
Add Reaction 1 and Reaction 2:
Left side:
$\text{Acetyl-CoA} + \text{Oxaloacetate} + H_2O + \text{Citrate}$
Right side:
$\text{Citrate} + \text{CoA} + \text{Acetate} + \text{Oxaloacetate}$
Cancel common species:
Citrate and Oxaloacetate cancel.
Net reaction:
$\text{Acetyl-CoA} + H_2O \rightarrow \text{Acetate} + \text{CoA}$
This is acetyl-CoA hydrolysis.
Step 3: Add free energies
$\Delta G' = \Delta G'_1 + \Delta G'_2$
$\Delta G' = (-670) + (-8192)$
$\Delta G' = -8862 \text{ cal/mol}$
Important Questions from Bioenergetics ATP Hydrolysis
- Assuming that there are $5 \times 10^{13}$ cells in the human body, and that ATP is turning over at a rate of $10^9$ ATP molecules per minute in each cell, then the human body is utilizing ________ watts (rounded off to two decimal places).
[Assume that hydrolysis of ATP yields 12 kcal per mole. 1 watt = 1 joule/sec, 1 calorie = 4.18 joules, Avogadro's number = $6.023 \times 10^{23}$] - Glucose and hexanoic acid, each having six carbon atoms can undergo complete biological oxidation. In terms of net ATP generation, which of the following statements is CORRECT?
- Four groups of metabolites are given below. Choose the group in which all the compounds contain at least one bond whose ${\Delta}G'^{\circ}$ of hydrolysis is $\leq$ -7.0 kcal/mole.
- Which one of the following statements is NOT correct?
- Which of the following is TRUE about Kreb's cycle?
