Use The Youtube Link to answer the following Questions: https://www.youtube.com/
ID: 191806 • Letter: U
Question
Use The Youtube Link to answer the following Questions: https://www.youtube.com/watch?v=Gpx6i8DXgks
Based at the diagram you drew, answer the following questions: A) How much energy is harvested in glycolysis (use ATP and potential ATPs as metric)? B) When is the oxidation of the glucose molecule completed? Explain what indicated that. C) What part/component of the glucose molecule is used in the electron transport chain? D) How does the electron transport chain contribute to ATP production? Cyanide poisoning causes a type of hypoxia by inhibiting cytochrome c oxidase, which is the very last protein in the electron transport chain. A) Explain how/why cyanide inhibition of cytochrome c oxidase interferes with cellular respiration. B) Does the cell have any alternative to keep glycolysis going? C) Explain the purpose of oxygen in respiration. A) Explain what would happen to ATP production in a mitochondrion that has “leaky membranes”, which would allow protons to diffuse through. B) Explain how the proton gradient contributes to ATP production.
Explanation / Answer
Answer:
1. (A) Glycolysis produces 4 ATP molecules by substrate level phosphorylation, although you had to invest 2 ATP in order to get the process started.
Thus, you have a net yield of 2ATPs. You also reduce 2 NAD+ molecules into NADH, in the presence of oxygen, those NADH molecules could yield 2.5 ATP molecules each, for an additional 5 ATP molecules. This adds up to 7 ATP, if oxygen is present, or 2 ATP molecules without oxygen.
(B) Glucose is oxidized into carbon dioxide and water. Thus, observing when the carbon dioxide is produced will give us an indication of when glucose is being fully oxidized. The first carbon dioxide molecules are produced during Pyruvate Oxidation, where one carbon dioxide molecule is produce for each pyruvate molecule.
This leaves us with two 2-carbon molecules: acetyl-coA. During Krebs cycle, two CO2 molecules are produced, marking the oxidation of the remaining 2 carbons of the glucose molecule. Keep in mind that pyruvate oxidation and Krebs cycle occur twice for each glucose molecule, since a glucose molecule has been split into two pyruvate molecules.
(C) By the end of the Krebs cycle, the glucose molecule has been completely oxidized. However, the high-energy electrons harvested from glucose are in the electrons carriers: NADH and FADH2. These electron carriers deliver those electrons to the Electron Transport Chain.
(D) Transport Chain uses the energy from the electrons carried by NADH and FADH2 and uses that energy to move protons (H+) against their concentration gradient forming an electrochemical gradient of highly concentrated protons in the intramembranous space.
That gradient is used by ATP synthases to power ATP synthesis during chemiosmosis.
2. (A) Cyanide binds to the last complex in the electron chain. CN then affects detrimentally the process as it inhibits oxygen from grabbing the electrons and stops the electron chain.
Since the electrons are not removed by oxygen,no new electrons can be added at the beginning of the electron chain. Furthermore, this halt in the electron chain causes the concentration gradient to decrease and equalize on both side thus, no protons move through pumpsand no ATP is produce.
The majority of ATP is produced in the electron chain. The ATP produced in glycolysis andin the Krebs cycle is not enough for the cell to subsist, therefore, the cell dies soon after the oxygen is stopped from accepting the electrons in the electron chain.
(B) Some cells have found other elements with electron affinity such as nitrogen to replace oxygen in their ATP production such as some prokaryotes. However, Oxygen is the element with most electron affinity thus, most productive.
When oxygen is not present some cells such as muscle cells, use fermentation that produces lactic acid. Fermentation is not ideal and does not produce additional ATP, but it replenishes NAD+ and FADH for the Kreb's cycle and glycolysis production.
(C) Oxygen is electron acceptor. It accepts the final electrons during the ETS.
3. (A) and (B):
ATP is produced in two ways: substrate-level phosphorylation and oxidative phosphorylation. Substrate-level phosphorylation is the transferring of a phosphate group to ADP (involving in glycolysis). Oxidative phosphorylation is when ATP is synthesized by ATP synthase (an enzyme) which uses energy from aproton gradient (chemiosmosis).
If there is a "leaky membrane," the 38 ATP molecules that are meant to be made per oxidized glucose molecule would not be reached and these processes will not be properly completed.
Proton pumps are protein complexes that move the protons generated in the oxidation reactions across the cell membrane.
Protons move through the pump and accumulate on the outside of the membrane, which creates a concentration gradient. Charged hydrogen ions are not able to diffuse back through the membrane, they need special channel which is enzyme called ATP synthase.
The movement of H+ ions thought the enzyme down the concentration gradient convert ADP to ATP. This process is called chemiosmosis. So if the membrane would be leaky the concentration gradient of protons would be disturbed and ATP synthase would loose its function in proton transportation and ATP would not be synthesized which would be fatal and the cell would die because ATP from other processes without chemiosmosis is not enough to keep the cell alive.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.