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Chapter 7 Blog: Cellular Respiration, Fermentation, and Secondary Metabolism (Robert)

Page history last edited by Robert Canuel Jr. 13 years, 8 months ago

In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.


A.  Daily Blog


Today we went into great detail in the process of glycolysis. Glycolysis happens with or without Oxygen. Glycolysis is also a universal process that can happen in a eukaryotic or prokaryotic cell. This process is taken in steps, in order to reduce the amount of energy amount of heat. The two types of enzymes that do most of the energy harvesting here are: kinases and dehydrogenases. A kinase is an enzyme that phosphorylates a molecule and transfers energy that way. A dehydrogenase is an enzyme that moves energy in the form of electrons. A particularly important enzyme here is phosphofructokinase as it is a highly regulated enzyme.


This time we looked the conversion of pyruvate to acetyl-CoA and the citric acid cycle. As a helpful tip Dr. Weber said that if the molecule ends in -ate then it's an acid. In the citric acid cycle most of the energy harvesting occurs in the oxdizing of the substrate, such as α-ketoglutarate and the reduction of NADH and FADH2. Whenever a molecule was oxidized, sometimes a CO2 would be produced. This happens when a carboxyl group is removed from the molecule. This is called decarboxylation. In the final minutes of class we had an energy count where we traced where the energy of the glucose was transferred into and where the energy intermediates were located. There were: 2 ATP in the cytoplasm from glycolysis and 2 in the mitochondrion from the citric acid cycle, 2 NADH in the cytoplasm from glycolysis and 8 in the mitochondrion from the conversion of pyruvate to acetyl-CoA and from the citric acid cycle, and 2 FADH2 which are both in the mitochondrion from the citric acid cycle.


We started the class off by recounting our energy tally. Then we proceeded into final step of aerobic respiration, the electron transport chain. This process uses the electrons that were stored in NADH and FADH2. Here NADH will lose its electrons to NADH dehydrogenase which loses them to cytochrome-b then to cytochrome oxidase and finally to Oxygen. Everytime the electrons are transported to a protein the protein actively pumps an H+ across the inner membrane of the mitochondrion and into the intermembrane space. Since the intermembrane space has a high concentration of H+, ATP synthase uses this gradient to power it in order to phosphorylate ADP into ATP. After discussing this we talked about what would happen if Oxygen was not present. The end result is the backup of the entire process of aerobic respiration and death. Cyanide has the same effect but it achieves it by taking Oxygen's place without accepting the electrons. Then we talked about a protein that allowed the H+'s bypass ATP synthase. This process creates heat and thus warms up the cell. Hibernating bears and infants have these proteins in order to keep warm.




B.  Useful Materials




Here's a smaller version of Dr. Weber's chart of cell metabolism. This shows that it isn't just about breaking things down. Cells can also build things back up.





Its an article on Mitochondrial metabolic signalling. mROS regulates something in the mitochondria and if it is unbalanced then the subject may develop metabolic disorders

Comments (1)

Derek Weber said

at 2:48 am on Oct 26, 2010

Missing updates 10/20 and 10/22.

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