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

Page history last edited by Maria Chiaffarano 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

Blog for 10/20/20 Lecture:

1st law of thermodynamics: Energy is converted from one form to another.

            Stores energy:

  •   Fats
  •   Electrons
  •  Gradients
  •  ATP
  • Carbohydrate
  • Proteins

Energy starts in nutrients, and then gets stored in electrons. 

Redox reactions – OIL RIG

1)      Oxidized when it loses an electron

2)     Reduced when it gains an electron


Carbohydrates ** Check is your notes***

            Glucose (C-H bonds) to 6CO2; it is an exergonic reaction; -686 kcal/mol


2nd law of thermodynamics: Entropy (randomness) increases with every reaction


  2 ways to make ATP

1)      Substrate level phosphorylation – 4 ATP

  1. Enzyme directly transfers phosphate from one molecule to another molecule

2)     Chemiosmosis

  1. Energy stored in an electrochemical gradient is used to make ATP from ADP and Pi  (mitochondria) 


Cellular Respiration – a way for cells to harvest energy; a way for living cells to obtain energy from organic molecules; the primary aim is to make ATP and NADH. 

1)      Aerobic respiration uses oxygen

  1. Oxygen is consumed and CO2 is released

2)     Focus on glucose but other organic molecules are used

3)     Make energy intermediates so they can drive endergonic reactions


The process steps are:

1)      Glycolysis

2)     Breakdown of pyruvate to an acetyl group

3)     Citric acid cycle

4)     Oxidative phosphorylation

The cytosol can produce about 2 ATP per glucose molecule but the mitochondria can produce about 30-36 ATP per glucose molecule.  Hence, mitochondria is known as the powerhouse of the cell. 


  •   Glycolysis
    • It can occur with or without oxygen
    • For each reaction in the many steps of glycolysis, a different enzyme is needed
    •  Steps in glycolysis is nearly identical in all living species
    • 10 steps in 3 phases
      • Energy investment – makes the molecule unstable
      • Cleavage (split the energy)
      • Energy liberation
  • A glucose-6-phosphate means that a phosphate is bonded to the 6th Carbon
  • Coupled reaction
  • 1st step
    •  Kinase – enzyme – transfers phosphates
    •  Hexokinase – transfers phosphates to a 6 carbon molecule – glucose
  • 2nd step
    •  Isomerase – same molecular formula, different structure
      •  Glucose – fructose
      •  Fructose 6 biphosphate
  • 3rd step
    • Another phosphate is added
    • Fructose 1,6 bisphosphate
    • Phosphor fructokinase (PFK)
    • *** most important step in aerobic respiration!!!!!!!!!!!!!!!!
    • Very unstable, must go “down the hill”
  • 4th step
    • Cleavage phase
      • Fructose 1,6 bisphosphate gets split up
      • Forms 2 molecules of glyceraldehyde-3-phosphate  - aldehyde carbonyl group in the structure  (also called G3P)
      • Lose a little energy as heat ~60% 
  • 6th step
    • G3P oxidized (exergonic)
    • NAD+ reduced to NADH (endergonic)  



Blog for 10/22/10


Cellular Respiration (cont)

      At the end of clycolysis, pyruvates are formed.  There are two ways to make ATP.  the way used after glycolysis is substrate-level phosphorylation.  Pruvate is pyruvic acid becuase it has a carboxyl group which is negative and therefore an acid.  

     Redox reactions are exergonic. 

     Kinases and dehydrogenases add and release energy!! They are important enyzmes!

     Oxygen is not needed for glycolysis but it is needed ino ther steps:

          If there is oxygen, puruvates taken to mitochondria, Acetyl CoA production and continues to Citric Acid Cycle

          NADH has a lot of potential energy

          Carbon Dioxide is produced as waste

Citric Acid Cycle

     gets rid of the rest of the potential energy

     3 steps

          1) Metabolic cycle

          2) Acetyl is removed adn added to oxaloacetate to form citrate/citric acid

          3) didn't get this one during lecture


The cycle begins and ends with oxaloacetate. 

CoA group helps preserve energy (decreases the amount of heat that is released/lost)

By the end of the cycle:

     6 NADH

     2 FADH2

     2 ATP

     4 CO2  (later there is a total of 6 CO2?)


***Glycolysis occurs in the cytoplasm and the citric acid cycle occurs in the mitochondria.   



Blog for 10/27/10 Lecture (submitted 10/27/10) :


We continued to learn about and review Cellular Respiration. 

  • The Citric Acid cycle occurs in the mitochondrial matrix
  • glycolysis occurs in the cytoplasm and is exergonic
  • Dehydrogenases are enzymes that remove electrons
  • The Electron Transport Chain is exergonic
    • It uses active transport, gradients, chemiosmosis,  ATP synthase, etc. 
    • It uses cytochrome and cytochrome - oxidase
  • Redox Reactions and Active Transport
    • creates gradients (unstable) 
    • chemiosmosis 
    • H+ gradients on outsid eof the matrix
    • Electron transport chain is in the inner membrane of the mitochonrdria 
  • ATP synthase - protein used for facilitated diffusion (brings protons back into the matrix)  



Blog for 10/29/10 Lecture:


Oxygen is limiting

     O2 is final electron acceptor in the electron transport chain, but if Oxygen is absent then the chain gets backed up.  NADH accumulates and NAD+ depletes

          NAD+ is needed to oxidize other molecules

                    glycoysis, breakdown of puruvate, and citric acid cycle decreases

glucose builds up as well as fats and proteins

ATP is depleted. 

Cell density - too many cells/mass

Cancer cells favor glycolysis over oxidative phosphorylation (Warburg - genes)

Good cure - inhibiting glycolysis but it would affect all cells and reduce ATP production (BAD!!!)


OXIDANTS - incompletely reduced species O2

     catalase breaks down H2O2


Anaerobic Respiration/Fermentation

     glycolysis in both

     fermentation does not include electron trasport chian or citric acid cycle (is not always carried out)

     Anaerobic respiration occurs when you are exercising and not enough O2 is brought in

          A lot of energy is lost as heat

          Build up of lactric acid causes fatigue and soreness



          *** Bacteria have their electron transport chain in their plasma membrane



Blog for 11/4/10 Lecture



  • Delta G is the measure of a change in free energy 
    • G is the available energy of a system 
    • Delta G = Gproduct - Greactant 
      • Negative sign means energy was released, spontaneous
      • Positive sign means energy was absorbed, nonspontaneous  
  • With an enzyme, it is the same kcal/mol because it didn't change delta G 
    • Does not affect delta G 
    • enzymes lower activation energy which speeds up reactions!  
    • Heat is cheap energy used to stablize reactions 
    • transition state - peak or top of the hill (most unstable state of the reactants) 
    • enzymes bring the reactants together to bind, bind in a way that strains bonds 
    • how can a cell make a non-spontaneous reaction, spontaneous? 
      • use of ATP
      • Coupled reactions! 
      • Phosphorylate - goes into phosphates 
      • Kinase is an enzyme that transfers phosphates! 
        • hexokinase - puts a phosphate on Carbon 6 
    • Glycolysis has two coupled reactions. What are they?? 
      • glucose + ATP + H2O ------> glucose 6 phosphate + ADP
        • breaking down glucose using hexokinase
        • adding phosphates adds energy 
      • fructose 6 phosphate -------> fructose 1,6 bisphosphate
        • investing energy using phosphofructokinase 
        • fructose 1,6 bisphosphate has the most free energy because of phosphates!!! 
  • NAD+ gets reduced
    • NADH drives electron transport chain 
      • after NADH is dehydrogenated, and turned into NAD+, NAD+ goes back to drive glycolysis, citric acid cycle, etc. 
    • Electron Transport Chain - exergonic reactions!!!! 
      • Can be used to drive endergonic reactiosn such as active transport, using gradients and is very unstable!! 
    • NOT 100% PROFICIENT! 
      • about 34.04% proficient  


B.  Useful Materials




Celllular Respiration Song (submitted 10/18/10)


YouTube plugin error       

This song provides an interesting take on describing the process of Cellular Respiration.  It is the song "I've Got a Feeling" but with different lyrics and sung by a high school biology teacher.  However, I am sure that Dr. Weber has a better singing voice...Haha.  It describes all the steps of Cellular Respiration including Glycolysis, the pyruvate, the Kreb's cycle, and Oxidative Phosphorylation. It's a catchy song and once heard enough times, the steps are easily memorized. 





Cellular Respiration (submitted 10/24/10: 


I like this web site a lot because it thoroughly explains the process of Cellular Respiration while including description diagrams/pictures.  I like how it breaks down the process and almost goes "slide by slide" or "concept by concept" so that you make sure you understand one step before moving onto the next.  This website really helps!!  




Journal Article:  Cellular Respiration (submitted 10/24/10):


This article talks about the cell cycle which is also known as cellular respiration.  It talks about how there are possibilities that cellular respiration can be linked to multiple diseases or malfunctions if it is not carried out properly.  Maintaining the intracellular and extracellular enivronments of a cell are very important for the survival of eukaryotic cells.  Recent findings have shown scientists that certain drugs? can be used as a homeostatic mechanism (good for the cell).   






Potential and Kinetic Energy (submitted 11/4/10):

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The above video gives some good examples of Kinetic and Potential energy (including the rubberband example!) in order to explain the differences between the two types of energy. 


Comments (1)

Derek Weber said

at 2:49 am on Oct 26, 2010

I really like the lecture outline approach. Nice work.

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