Closed 12/22 Mr F. 

Totaled 11/23 Mr F

The Krebs Cycle: Second stage of cellular respiration

• During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Aerobic respiration requires oxygen in order to generate energy (ATP). It is the preferred method of pyruvate breakdown from glycolysis and requires that pyruvate enter the mitochondrion in order to be fully oxidized by the Krebs cycle. The product of this process is energy in the form of ATP (Adenosine Triphosphate), by substrate-level phosphorylation, NADH and FADH₂.

Krebs cycle- second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

Electron transport chain-a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP

-This video shows how the Krebs cycle, or Citric Acid cycle, works (how the oxidation of glucose is continued). This process takes place in the mitochondria of a cell.

-The following site is an animation of the Krebs Cycle, it is from a reliable lecture source:

http://www.1lecture.com/Biochemistry/How%20the%20Krebs%20Cycle%20Works/index.html

The Krebs cycle is involved in the second of three major stages every living cell must undergo in order to produce energy, which it needs in order to survive. The enzymes that cause each step of the process to occur are all located in the cell's "power plant." In animals, this is the mitochondria; in plants, it is the chloroplasts; and in microorganisms, it can be found in the cell membrane. The Krebs cycle is also known as the citric acid cycle, because citric acid is the very first product generated by this sequence of chemical conversions.

This is a Diagram of the Kreb Cycle. The Kreb Cycle occurs after glycolisis. This is where a 3 carbon chain (a pyruvate) has its bonds broken to charge the NAD+ to NADHs and to release CO2. This cycle is critical because without transfering the energy from the bond of the glucose/pyruvate then NADH would not be created and that powers the electron transport chain which creates ATP which is power source used for cell work that keeps us alive.

http://www.youtube.com/watch?v=BIJfeWoK3J8

The video in the link above is ALOT less confusing than any other video I have seen about the Krebs cycle. It explains not so indepth that it confuses you about what happens during the cycle and the end products that are used later in the ETC.

This site is great! It teaches you with step by step processes and also has you put pieces together!

I don't think you can just click on it, because it wont work.  Just copy it and paste it into your address bar and it'll work that way!

http://www.wiley.com/legacy/college/boyer/0470003790/animations/tca/tca.htm 

     This is the second stage in cellular respiration, and is also known as the citric acid cycle.  Unlike glycolisis, the krebs cycle is aerobic, which means that it needs oxygen in order to create ATP and NADH.  In this cycle the pyruvates from glycolisis are even further brocken down into CO2 molecules.  During this process, the bonds are broken in order to get more energy.  This energy is used to make a few ATP and a few NADH.  The CO2 diffuses out slowley into the blood, and then is transported to the lungs where it is exhaled. 

Krebs Cycle (Citric Acid Cycle)

• Takes place in the matrix of the mitochondria.
• Takes place in the presence of oxygen.
• The pyruvic acid produced produced by the glycolysis is turned into Acetyle CoA which is made up of 2 carbon atoms, 1 oxygen atom, and 3 hydrogen atoms
• The Acetyl CoA goes on to produce Citric Acid.
• The citric acid is broken down further and the carbons being broken off attach to an O2 molecule and produce CO2.
• The 4 carbon molecule left over is ready to accept another pair of carbons and start the cycle again.
• For each turn on the cycle an ADP molecule is converted and an ATP molecule is produced
• The NAD+ molecules are converted to NADH.
• The FADH2 molecules become FAD
• The CO2 molecules produced during the Krebs Cycle are expelled when we breathe.
• The NADH produced are used to generate large amounts of ATP by the Electron Transport Chain

http://www.wiley.com/college/pratt/0471393878/student/animations/citric_acid_cycle/index.html

     This video is an informational video about the Citric Acid Cycle made by college professors which sequentially explains each component in depth to acquire a deeper understanding.

http://www.johnkyrk.com/krebs.html *if the link does not work then just type it into the URL bar

     This is a website that goes really in depth with the krebs cycle involving moving diagrams where you can view each step of the krebs cycle at one time. It should help you to understand the krebs cycle alot more.