BSCI207
HW#2. Thermodynamics and metabolism Due 9/10/19 6pm
1. Sucrose is composed of glucose linked to fructose where both of the monosaccharides
have the same composition (C6H12O6) though with different conformations. When sucrose
is oxidized, it releases 1350 kcal/mole of energy. Some of this energy gets converted into
ATP, with each molecule of ATP storing 7.3 kcal/mole of energy.
a. If all the energy from sucrose oxidation was converted and stored in ATP, how many
ATP molecules would be produced from each molecule of sucrose?
b. In actuality, approximately 72 molecules of ATP are produced. What fraction of
the available energy ends up as ATP?
c. Where does the rest of the energy go?
This study source was downloaded by 100000830604181 from CourseHero.com on 09-11-2021 21:01:26 GMT -05:00
https://www.coursehero.com/file/62015428/HW2-thermo19-copydocx/
This study resource was
shared via CourseHero.com
2. ATP is often used to drive reactions that would not occur spontaneously. The three
phosphate groups are electron rich and tend to repel each other. Therefore, ATP is a bit
like a compressed spring, ready to kick off one phosphate group releasing energy. This
energy is then used to drive other reactions that an organisms needs to make essential
components such as amino acids. Consider these two reactions:
ATP -> ADP + Pi G= -7.3 kcal/mol
Glutamic acid + NH3 -> Glutamine G= 3.4 kcal/mol
The glutamine reaction is endergonic and so not spontaneous. How could having these
two reactions occur at the same time result in glutamine production?
Draw a diagram showing the relative energies for the reactants and products of the first
reaction. Then show the relative energies for the reactants and products of the second
reaction. Finally show the energies of the reactants and products for the combined
reaction. How does adding ATP help produce an endergonic reaction?