Biochemical Pathways Take Home lI 6.) Used the following oxygen consumption curv
ID: 256576 • Letter: B
Question
Biochemical Pathways Take Home lI 6.) Used the following oxygen consumption curve to answer the subsequent 3 4 5 questions. Between which two numbers would you calculate state 2 respiration? How about state 3 respiration? How would you expect the trace to change if the mitochondria were isolated from a brain sample that had been damage by stroke? What would happen to the trace if you added DNP at point 5? What would happen if you added rotenone? In your answer describe what each of these chemicals do. If your state 2 respiration rate was 2mM 02 consumed/second and your state 3 respiration rate was 4mM O2 consumed/ second what would your respirator control ratio (RCR) be? What does your RCR tell you? Explain what the P: O ratio is and what that measurement can tell you a. b. c. Time (sec) d. e. aundntion Wehsite or other outside sources to research this question. toExplanation / Answer
Please find the answers below:
Answer 1: State-2 respiration in mitochondrial oxidative phosphorylation refers to the point where electron tranport takes place from complex I to complex II. Thus, this state of respiration can be measured between points 1 and 2 in the graph.
Answer a: During the condition of stroke, the oxygen availability to the tissue undergoes rapid decrement or complete cut off. Since oxygen comes into play during the last phase of mitochondrial electron transport chain i.e. phase 4 and 5, the phase 4 will suffer from a drastic stop and no connectivity would form between points 4 and 5.
Answer b: DNP is a chemical blocker of transport of electrons from complex IV to V, hence its addition will prevent reduction of oxygen to give rise to water during transport from complex IV to V. On the other hand, rotenone is a chemical blocker of tranport of electrons from complex I to complex II. Hence, addition of rotenone will prevent all the electron transport chain in the mitochondria.
Answer c: Respiration control ratio or RCR is defined as the amount of ATP generated per unit transfer of electrons to complex V. Here, the fraction of eletrons tranported via complex II is given by 4/2 or 2, hence RCR is given by 2.
Answer d: This large value of RCR implies that the mitochondria are conducting aerobic respiration very effectively and hence requisite amount of ATP would be generated from these energy-houses.
Answer e: Technically, the P:O or phosphate to oxygen ratio represents the total number of molecules of ATP generated per unit transfer of a pair of eletrons across the mitochondrial electron transport chain. This ratio infers the activity of electron transport chain and represents the efficiency of mitochondrial oxidative phosphorylation. More is the ratio, more is the ability of mitochondria to generate ATP per unit oxygen consumed.
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