Question 1
For succinate oxidation to fumarate there is yield of 2H+ and 2 electrons; however, the process of the reaction skips one step thereby leading to 2 ATP. 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, with production of 2H+ and 2 electrons 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 = - 0.06 V.DG = (1)(96.48 kJ/V-mol)(- 0.06V) = - 5.79 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 – 5.79 kJ/molDG = -13.78 kJ/mol
30.5/13.78 = 2.21
The estimated moles protons should be 2
That is = 2 moles protons per mole. when considering Hess’s law,
Question 4
Atractyloside 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. The inhibition effect of atractyloside occurs when it achieves a binding with ATP-ADP translocase found on the side of the cytoplasm, thereby lodging it inside a cytoplasmic side open conformation. In which case, this contributes to an inhibitory effect on oxidative phosphorylation, also called the energy-transfer system. The result of all these is a barrier to respiration in mitochondria.
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. In this zone, antimycin inhibits cytochrome b6f by preventing Q cycle from converting QH2 -> Q. it acts in the cyclic pathway that is meant for oxygenic photosynthesis thereby inhibiting the activity of the b6f complex.
Question 6
Calvin cycle start with three ribulose-5-phosphates cleaves the ribulose in half and adds CO2. The following is an illustration indicating where CO2 is located throughout the calvin cycle. In the first stage, CO2 involves in a reaction with RuBP thereby yielding 3-carbon molecules of 3-PGA.This makes up the C3 cycle. The regeneration of RuBP throughout the cycle prepares the system for increased fixation of CO2 along the way. In which case, the fixation process of CO2 occurs from an inorganic to organic molecule in the cycle.
Question 7
The C4 plants remains to thrive because it adapts well to moisture condition. The C4 plant in such a case are better placed in the utilizing the CO2 efficiently than C3 plants. In such a moisture condition, the two plants will fight for the limited CO2 to be used in photosynthesis and C3 plant will end up dying because it cannot use the available CO2 efficiently. In which case, the photorespiration problem will readily affect C3 plant because it hinders photosynthesis. C4 plant avoids the problem of photorespiration keeping the levels of CO2 high and oxygen levels low in the zone of calvin cycle operatiion; 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, which can with stand the problem.
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 participate actively in 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
There is necessity for an elevated Vmax in muscle enzyme in order to facilitate muscular activity. This is especially true when the muscle are subject under a condition of lower levels of oxygen concentration. Both glucose (acting as an inhibitor) and hormones controls glycogen phosphorylase, a muscle enzyme isozyme, that is located in the liver. Phosphorylase is useful in muscle where it generates glucose required for catabolism; catabolism in turn produce ATP required for muscle activity. In most case, the skeletal muscles are at a state of rest while the glycogen phosphorylase is identified to be in the T state. High kcat and activity of muscle glycogen phosphorylase is activated by AMP. For the liver, the major function of glycogen phosphorylase is to control levels of blood glucose to a normal level; thereby helping to avoid any form of unintended variation.
Question 10
Constant hunger and need to eat often; There is an enzyme defect in glucose-6-phosphatase so that glucose-6-phosphate cannot be converted into free glucose but is metabolized to lactic acid or incorporated into glycogen.
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 and the liver.
Irritability; the excess amount of glycogen in the body causes the body to be very sensitive. This is any extra energy required is going to be obtained from external sources.
Question 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
The individual units achieve transient attachment, in the reaction process, to the enzyme. For transketolase, the addition site for the units is regarded as the thiazole ring usually associated with the coenzyme thiamine pyrophosphate.
Question 12
In the process of lighting, ferredoxin functions in reduction of thioredoxin disulfide to the diathol. The active enzyme used in this case is Ferredoxin-Thioredoxin Reductase. This enzyme participate in reducing disulphide bond. The formation of carabamate result from the reaction of e-amino group with HCO3-, aided by the presence of Mg++. The group of e-amino is a product of lysine residue resulting from RuBP T caboxlase. The formation of carbamate through the reaction of HCO3-is much different from the CO2 that achieves binding with RuBP Carboxylase in the form of substrate. The excess amount of CO2 when disintegrate in solution during the formation of ATP. This makes the pH to be above seven that is alkaline, this is neutralized by the H+ from water molecule. Both the reaction work best at pH 7. The reactions are regulated in plants by the plants increasing the pH level to above seven usually around nine.
Question 13
The first step involve removing the phosphate group coupled by the conversion of the molecule resulting to glycolic acid. The transportation of the glycolic acid then occurs, heading to the peroxisome, from which it transitions to glycine. This is followed by transportation of the glycine into the mitochondria where there is conversion to serine. The produced serine is singnificant given that it can be used in making of some organic molecules. These conversions, when all coupled, results to more energy spent by the plant and leads to CO2 loss. In order to prevent this process, it comes handy to use two forms of metabolism (C4 and CAM) considered to have been evolved to specialized biomedicalad additions. Malate levels remain low in the presence of PEP carboxylase. This occurs when there is export headed towards the bundle-sheath cells associated with the C4 pathways. I Further, for CAM plants, there is importing targeted for the vacuole. Besides, phosphorylation of PEP carboxylase is yet another regulation means that can be used besides the alternative pathways. This normally requires the presence of light.
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. Nature432, 779-782 (9 December 2004) | doi:10.1038/nature03145; Received 13 August 2004; Accepted 1 November 2004
