Krebs cycle
Krebs cycle
Krebs cycle also known as citric acid cycle or tricarboxylic acid cycle takes the final product of pyruvate oxidation, Acetyl-CoA to produce more ATP. Krebs cycle occurs when oxygen is present when no oxygen is present fermentation occurs, this is known as anaerobic respiration; to learn more about that go to the anaerobic respiration from the home page. Krebs cycle is a series of 8 reactions starting with acetyl-CoA being combined with four carbon molecule oxaloacetate to produce six carbon molecule citrate. Citrate is then converted into isocitrate, in the picture below you ca see that one of the red carbons with its oxygens comes off as CO2 and NAD+ is reduced by taking the hydrogens from that carboxyl group. This reaction creates alpha-ketoglutarate which means the next red carboxyl group is in a prime location for the next CO2 to be removed and NAD+ becomes reduced once again by taking hydrogen. This create succinyl-CoA which converts to succinate and while this happens the GTP GDP cycle occurs and helps produce ATP. Once succinate is made FAD comes in to take more hydrogens and you are left with furmerate. Water then comes in to help make malate which is oxidized by NAD to come all the way back to oxaloacetate. Remember this cycle occurs twice because you have two acetyl-CoA molecules.
Teaching resources
Below are a few teaching resources that one can use to help reinforce Krebs Cycle for students
HOOK
Use this as an interesting hook that will help peek interest of the students
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STudent worksheet
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Received from : http://www.bxscience.edu/ourpages/auto/2011/2/22/38430462/krebs%20cycle%20wksheet%20ans.pdf
Activity- The Pantomime
Received from L.Philips
Create signs of all the major metabolites from the pyruvate oxidation and Krebs cycle. Use Velrco on the back of the metabolites that have water taken out or CO2 ect. Using those card students will re-enact what occurs during those stages of cellular respiration. Make sure to make the connection that acetyl CoA comes from pyruvate oxidation and goes into the Krebs Cycle.
What you will need:
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assessment
Help reinforce and check student understanding you can allow students to check what they know using this self quiz. The self quiz can be given to students as study resource or even at of the end activity to check understanding. Also there is a link for a animation that can be used as reinforcement for when you have finished teaching the Krebs Cycle.
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