Question 1
FAD is reduced to FADH2 in Succinate oxidation to fumarate through catalytic action of succinate dehydrogenase. The resulting FADH2 electrons skips the first stage of oxidative phosphorylation by moving into the electron transport chain located in CoQ. This can be illustrated as NADH -> CoQH2. Consequently, there is 2 ATP forming stages found in the electron chain from CoQ to O2 used in this course (Schwender et al, 50). Indifferent to the first scenario, oxidation of malate to produce oxaloacetate results to NADH consequently, the NADH produced electrons completes its movement in 3 ATP forming steps associated with chain of electron transport.
Question 2
The nigericin aids in exchange of K+ for H+ ions, which then activates discharge of proton gradient through the inner membrane of the mitochondria. Given that electron transport generates the proton gradient and the same gradient is released by the action of ATP synthase-mediated formation, nigericin is found to uncouple the two processes (Gottlieb & Paul, 36). In which case, this means that there will be continuation of electron transport while ATP synthesis will not continue. Valinomycin does not do the same because it is not capable of transporting protons; consequently, its action will generate scanty impact on either of the processes, transport of electron or synthesis of ATP.
Question 3
Free energy that is attributed to the concentration gradient when the Ph gradient is maintained at 1.4 units
DpH = + 1.4
DG = - 2.303 (8.315 x 10-3 kJ/mol-K)(298K)(1.4) = - 7.99 kJ/mol
Computation of free energy that is attributed to the voltage gradient
Dym = yin - yout = - 0.14 V.DG = (1)(96.48 kJ/V-mol)(- 0.14 V) = - 13.5 kJ/mol
Computation of the free energy available for 1 mole of protons’ movement starting from the cytoplasm right into the matrix considering the cellular condition will be the sum of energy calculated above. That is:
DG = - 2.303 RT DpH + nFDy = -7.99 kJ/mol - 13.5 kJ/molDG = -21.5 kJ/mol
The estimated moles protons should be 3
That is = 3 moles protons per mole. when considering Hess’s law,
Question 4
Atractyloside acts inhibits respiration by acting as an inhibitor to transport of materials, that is raw materials import across the inner membrane of the mitochondrion; it also hinder ATP export. The atractyloside functions by blocking the adenine nucleotide porter when it binds to the outward. In which case, their action results to inhibition of oxygen consumption in mitochondrial proximal tubule.
Question 5
Antimycin site of inhibition is found in the photosynthetic and the respiratory electron transport chain located between the b and c types cytochrome (Ormerod, 34). This zone is known as plastoquinones. This reasoning is quite true since the two cytochrome are found in the location of photosynthetic action; that is photochemical –oxidizing point is located near the c-type cytochrome while the photochemical-oxidizing location is found closer to the b type cytochrome. Consequently, by acting in this zone antimycin is capable of actively inhibiting photosynthesis in the chloroplasts.
Question 6
Average Calvin cycle labelling patterns should be in reliant to the elements given in question.
Question 7
The C4 plants remains to thrive because it adapts well to hot and dry systems. This is therefore contributes to the fact that illumination will not affect C4 plant, while affecting C3 that is not better suited. In addition, C4 plant has significantly lower amount of photorespiration; consequently, in a sealed box where we expect O2 concentration to be high, photorespiration will act as a major aspect contributing to the dying of C3 and accommodation of C4.
Question 8
a). The Ca 2+ ions activate PKC in conjunction with DAG. Increase the amounts of calcium ions are going to result in the increase in the rate of glycogen synthesis and decrease in degradation of the glycogen.
b). once released the inactive catalytic subunits of PKA phosphorylate numerous substrate using the phosphate donor. This implies that increase in ATP increases the process of glycogen synthesis and reduces the rate of degradation.
c). When adenylyl cyclase is activated, it catalyses the conversion of ATP to cyclic AMP, which leads to an increase in intracellular levels of cyclic AMP. Inhibiting adenylate cycles results to decrease in rate of glycogen synthesis and increase in the rate of degradation.
d). Glucagon and epinephrine trigger the breakdown of glycogen. Increasing the amount of epinephrine in the blood increases the rate of glycogen degradation. The increase also results into decrease in the rate of glycogen synthesis.
e). The cyclic AMP cascade highly amplifies the effects of hormones. If they amplify the effect of epinephrine then the rate of degradation of glycogen increases rapidly and the rate of synthesis also decreases rapidly.
Question 9
Muscle enzyme needs a higher Vmax for strenuous muscular activity, particularly when the muscle is working under much reduced oxygen concentrations. Glycogen phosphorylase in the liver is an isozyme of the muscle enzyme, and regulated by glucose (inhibitor) as well as by hormones.
Question 10
Constant hunger and need to eat often; this is because all the energy is to be supplied to the body from external sources of glucose.
Easy bruising and nosebleeds; there is no enough energy in the body.
Fatigue; this is as a result of concentration of excess glycogen in the muscle.
Irritability; the excess amount of glycogen in the body
Puffy cheeks, thin chest and limbs, and swollen belly; the amount of glycogen that are not degraded results to this
11).
Similarities
They both stabilize carbonionic intermediates. They do this using different mechanism. For transketolase and transaldolase, a carbanion intermediate is stabilized by resonance.
Differences
One difference is that transketolase transfers a two-carbon unit, whereas transaldolase transfers a three-carbon unit. Each of these units is transiently attached to the enzyme in the course of the reaction. In transketolase, the site of addition of the unit is the thiazole ring of the required coenzyme thiamine pyrophosphate. Transketolase is homologous to the E1 subunit of the pyruvate dehydrogenase complex and the reaction mechanism is similar.
In transketolase, TPP stabilizes this intermediate; in transaldolase, a protonated Schiff base plays this role.
12).
During illumination, the thioredoxin disulfide is reduced to a dithiol by ferredoxin, a constituent of the photosynthetic light reaction pathway, via an enzyme Ferredoxin-Thioredoxin Reductase.
The carbamate forms by reaction of HCO3- with the e-amino group of a lysine residue of RuBP Carboxylase, in the presence of Mg++. HCO3- that reacts to form the carbamate group is distinct from CO2 that binds to RuBP Carboxylase as substrate.
13).
C4 and CAM plants have, over evolutionary time, evolved a different enzyme to serve in the (initial) fixation of carbon dioxide. PEP Carboxylase has a higher affinity for carbon dioxide than Rubisco and serves to fix carbon dioxide into an organic intermediate molecule. The presence of PEP Carboxylase in C4 and CAM plants reduces photorespiration (Ormerod, 46).
Work cited
Gottlieb, David, and Paul D. Shaw. Mechanism of Action. Berlin, Heidelberg: Springer Berlin Heidelberg, 1967. Internet resource.
Ormerod, J G. The Phototrophic Bacteria: Anaerobic Life in the Light. Berkeley: University of California Press, 1983. Print.
Schwender, Jorg, Goffman, Fernando, Ohlorogge, John and Shachar-Hill, Yair. Rubisco without the Calvin cycle improves the carbon efficiency of developing green seeds. Nature 432, 779-782 (9 December 2004) | doi:10.1038/nature03145; Received 13 August 2004; Accepted 1 November 2004
