A. Daily Blog
10/20/10: Today we weren't completely done with Chapter 6, so we reviewed the first law of thermodynamics and how that applies to cellular respiration. We talked about reduction and oxidation, processes in which a substance gains or loses an electron. We also talked about ATP and other energy intermediates, such as NADH. That started us on Chapter 7 , and the process of cellular respiration. This process can be broken down into give or take 20 steps, but the broad generalization leaves us with 4 steps: glycolysis, the breakdown of pyruvate, the citric acid cycle, and oxidative phosphorylation. We talked about each of the steps in glycolysis and the breakdown of pyruvate, including the enzymes that took acted in the procedure and what actually happened. We ended lecture with Dr. Weber being very impressed with our efforts and understanding of the subject.
10/23/10: Today we reviewed the first step of cellular respiration, glycolysis. Then we moved onto the citric acid cycle. The net production for the citric acid cycle is 2 ATPs, 8 NADHs, and 2 FADHs. Basically in this procedure, several dehydrogenase enzymes break apart hydrogen from the product of the previous reaction and it is added to NAD+ or FAD+ to make NADH or FADH. 2 ATP are also produced by removing P from GTP to create ATP and GDP.
10/27/10: Class started with review on glycolysis and the citric acid cycle and their net gains. We then moved into oxidative phosphorylation, which includes the electron transport chain. We start out with NADH, which moves to NADH hydrogenase, and eventually oxygen is reduced to produce water. Then ATP synthase takes those H+ ions, and through facilitated diffusion, turns them into ATP. ATP synthase is interesting in the fact that its conformational change is to turn while producing ATP. Although when the cell is in anaerobic conditions, things get difficult. Because there is no oxygen, the H+ gradient slowly disappears. When the cell finally reaches equilibrium, ATP can no longer be made, because ATP synthase was driven by the facilitated diffusion of the H+ ions. When ATP synthase can no longer work, that effects the whole electron transport chain and it becomes backed up. As a result, this effects the whole process of cellular respiration, and we back up to glucose.
10/29/10: Today we received some exciting news! The ipod touches had just come in, and Dr. Weber had picked them up to bring to class! After settling the class down, we reviewed cellular respiration, and then compared it to fermentation and anaerobic respiration. We talked about how bacteria and other organisms cannot use oxygen as the final electron acceptor. Dr. Weber even said that the slightest amount of oxygen could kill certain bacteria. We also discussed second metabolites, but that wasn't going to be on the test. To end the class, Dr. Weber set down the rules for using the ipods in class. We can't wait to use them, and luckily, the Friday lab class got a chance to use them!
11/3/10: We reviewed for the test today. We ran through all the cycles and talked about the complications of backing up the electron transport chain (the entire process of cellular respiration would back up).
11/5/10: Test today!
B. Useful Materials
This video summarizes the final stage of cellular respiration, the electron transport chain. It explains how the procedure is carried out and the net gain of the electron transport chain in addition with the other stages of respiration.
This video is brief, but explains anaerobic respiration and how not as much energy is produced. This shows that the most effective products are produced when oxygen is present in the cell.
This article talks about a study done with children ages 9-13. Through experimentation, scientists have discovered that the course of cellular respiration can be affected due to the stage of sleep a person is in. Although, this is only exhibited in children of the ages shown previously. Scientists concluded that these pauses are normal for children, the longest pause recorded was 25 seconds.