Home » Biology » How to memorize the Krebs Cycle (Citric Acid Cycle)

How to memorize the Krebs Cycle (Citric Acid Cycle)

Many college student go crazy when they are first presented with the task of memorizing the Krebs/ Citric Acid cycle. So many steps and enzymes and carbon dioxides flowing around. Guess what. There is a very easy way to remember it, AND retain it for years to come without ever looking back in the book.

[gn_note color=”#00aa00″]Check out the Krebs Cycle “Drag n Drop Game” for more practice Here![/gn_note]

….and we have 2 molecules of acetyl CoA to start with. If you don’t understand that please see the post about glycolysis.

I will go over how i memorized the names of all the molecules in the Krebs cycle, then the enzymes between each step, and then finally…if you are up to it how to draw each molecule. The easiest way to get this dreadful cycle in your head is by using mnemonics. This will take practice and its best that you don’t try to study this for the 1st time the day before the test.

[gn_divider top=”1″]

The Mnemonic Technique

To remember the molecules of the citric acid (Krebs) cycle i remeber this phrase as a hint to what molecules come first in the Citric Acid Cycle:










You should not just look at this and try to remember it. You should look at this, say it out loud, and write it down several times by memory. This helps people learn in a visual, auditory, and hands on manner. Once you are very familiar with these terms you should almost be able to recite them without the mnemonics.

*note: Citrate= Citric Acid, Fumarate= Fumaric Acid, etc…

Cictric Acid Cycle molecules
Molecules of the Citric Acid Cycle


[gn_divider top=”1″]

Citric Acid Cycle + Enzymes

For MOST of the enzymes, the name of the enzyme consist of the molecules it modifies(the molecule directly before it, and the function the molecule carries out):

So———-citrate Synthetase



Dance———-isocitrate Dehydrogenase

Devon———-alpha-ketoglutarate Dehydrogenase

Sipped———-Succinyl-CoA Synthetase

Down———-Succinate Dehydrogenase


Drinks———-malate Dehydrogenase

Cictric Acid Cycle enzymes
Cictric Acid Cycle enzymes


The key to remembering how many CO2 or NAD H is made you just need to remember that 3 out of the 4 dehydrogenase enzymes will remove 2 H atoms(and an electron)  from the molecule an put it onto a NAD, and remove a carbondioxide(CO2) molecules. That NAD will become NADH2. The only exception to this rule is the enzyme that produces Fumarate; Succinate Dehydrogenase. It actually places 2 H atoms on an FAD molecule instead of an NAD molecules. See pic above


[gn_divider top=”1″]

Citric Acid Cycle Molecular Level

I have finally found time to to create the image showing the citric acid cycle at the molecular level. The picture is self explanatory with comments where I thought they were necessary. Feel free to post suggestions or feedback. I would really appreciate it!

The Citric Acid Cycle at the Molecular Level:

Citric Acid Cycle Molecular Level


[gn_divider top=”1″]

What is next?

After completing glycolysis and the Krebs Cycle (Citric Acid Cycle) inside of your cells there is still a net production of only 4 ATP. In order to produce more ATP the molecules of NADH and FADH2 travel from the matrix of the mitochondria to the inner membrane. If you think you are ready for the electron transport stage of cellular respiration then click here.

[gn_divider top=”1″]

Other Related Processes

[gn_column size=”1-3″ last=”0″ style=”0″]


[/gn_column] [gn_column size=”1-3″ last=”0″ style=”0″]

Benefits of Fiber

[/gn_column] [gn_column size=”1-3″ last=”1″ style=”0″]


[/gn_column] [gn_divider top=”1″] [gn_spoiler title=”Literature referenced in this article:” open=”0″ style=”1″]

Brooker,Windmier,Graham, and Peter Stiling. Biology. McGraw-Hill   Science Engineering Math, 2007. Print.
Mauseth, James. Botany: an introduction to plant biology. 4th. Jones & Bartlett Learning, 2009. Print.

Check Also

blue strawberry

Can Synesthesia Reveal We Dont See The Same Colors

Have you glared at the sunset in the horizon wondering if the blue sky you …


  1. I think you may want to put a facebook button to your website. Just marked down the blog, however I had to make this manually. Just my $.02 🙂

  2. thanks for the advice. I will definitely add that feature to the blog.

  3. Great Post!! Thank you very much!

  4. Thank you for your article.Really looking forward to read more. Keep writing.

  5. Great post, I admire the writing style 🙂 A little off topic here but what theme are you using? Looks pretty cool.

  6. Appreciate your inforamtion. It is just too greeeeat!

  7. Thanks. I modified a theme called Elegant grunge by Michael Tyson. I used a mix of css and and a little php to change the theme. My goal was to integrate the blog with my personal website’s theme.

  8. Superb website. A lot of usefull information might be identified right here. I like your composing rather much. I am sending it to a number of pals and also sharing in tasty. And of course, thank you on your energy. Valuable information and facts. Definitely lucky me I uncovered your site. You’ll not believe that it, i identified it accidentally i was interested in on the internet ups, and I am shocked why this accident did not occurred earlier. I bookmarked it.

  9. I am glad to be one of the visitors on this great web site (:, thanks for putting up. -Adriane

  10. okay without appearing too sticky or groupie’ish you are amazing for posting this aha thanks man

  11. excellent points altogether, you just gained a new reader.What would you suggest in regards to your post that you made some days ago? Any positive?

  12. As I website possessor I believe the content matter here is rattling excellent , appreciate it for your hard work. You should keep it up forever! Good Luck.

  13. I think other web site proprietors should take this web site as an model, very clean and wonderful user friendly style and design, as well as the content. You are an expert in this topic!

  14. 5 star article brilliant. I am new to blogging and you used a langauge I can understand

  15. Undoubtedly a powerful written piece! We’ve saved it and emailed this out to every one of my friends as I know they’ll be interested, thank you very much!

  16. christian louboutin

    Happened across your article while searching via yahoo. I examine the very first paragraph and its great! I do not have enough time to finish it now, but I have bookmarked your website and will understand the rest tonight. : )

  17. Great article. Thank you to tell us more useful information. I am looking forward to reading more of your articles in the future.

  18. Hi, I love your weblog. Is there some thing I can do to obtain updates like a subscription or some thing? Im sorry Im not acquainted with RSS?

  19. Thank you a lot for sharing this with all of us you actually know what you are talking approximately! Bookmarked. Kindly additionally visit my site =). We could have a link alternate contract among us! Zeri

  20. Terrific work! This is the type of info that should be shared around the internet. Shame on Google for not positioning this post higher! Come on over and visit my web site . Thanks =)

  21. I together with my pals were analyzing the nice information and facts found on your site and all of a sudden got a terrible feeling I had not expressed respect to the blog owner for them. All the young boys happened to be consequently thrilled to study them and have now certainly been having fun with these things. Appreciate your turning out to be considerably accommodating and for utilizing this kind of extraordinary subjects millions of individuals are really desirous to learn about. My sincere apologies for not expressing gratitude to you earlier.

  22. You made some great points there. I did a search on the subject and found most guys will agree with your blog.

  23. Its like you read my mind! You seem to know a lot about this, like you wrote the book in it or something. I think that you can do with some pics to drive the message home a bit, but other than that, this is fantastic blog. A fantastic read. I will certainly be back.

  24. Hi, Neat post. There’s a problem with your website in internet explorer, would check this… IE still is the market leader and a large portion of people will miss your wonderful writing because of this problem.

  25. I do enjoy the manner in which you have presented this specific issue plus it really does supply us a lot of fodder for thought. Nonetheless, coming from just what I have observed, I just simply hope when the actual feed-back pack on that men and women continue to be on issue and don’t embark on a soap box involving some other news du jour. Still, thank you for this fantastic piece and though I do not necessarily concur with this in totality, I respect your point of view.

  26. great post! I love it 🙂

  27. Hi there, I found your website via Google while looking for a related topic, your site came up, it looks great. I’ve bookmarked it in my google bookmarks.

  28. I was suggested this blog by my cousin. I’m not sure whether this post is written by him as nobody else know such detailed about my trouble. You are wonderful! Thanks!

  29. hey there and thank you for your info – I have definitely picked up anything new from right here. I did however expertise several technical issues using this web site, as I experienced to reload the web site lots of times previous to I could get it to load properly. I had been wondering if your web host is OK? Not that I’m complaining, but sluggish loading instances times will very frequently affect your placement in google and can damage your high-quality score if ads and marketing with Adwords. Well I’m adding this RSS to my email and can look out for a lot more of your respective exciting content. Make sure you update this again soon..

  30. I would like to thank you for the efforts you have made in writing this article. I have bookmarked your website and your writing abilities has inspired me.

  31. I have fixed several issues that might be related to the slow loading times you were experiencing. If it wasn’t for comments i might not have caught that for a while

  32. Great site for students, but you may wish to correct your spelling of ketogluMarate to ketogluTarate which is the correct biochemical naming.
    Richard Day PhD

  33. Thanks for catching that. I will make note of that near the image until I recreate it with Photoshop

  34. Thanks a ton!!
    Was having tough time with this cycle.
    Finding it very easy now 🙂
    Great work !!!!!

  35. Thanks. I’m happy to hear I helped.

  36. I really like your memorytechniques. However I miss one for the glyconeogenesis. It would be very nice if you’d make one for that cycle as well :).

    Thanks a lot for this magnificent effort !!

  38. no problem man. Just trying to spread the info that helped me through college.

  39. Awesome webpage!

    Another mnemonic for the substrates that should be difficult to forget:
    Caroline Candy Is A-Krazy Super Sexy Fox Mating Oxes

    Thanks again for the help with my Biochem 🙂

  40. That first part can be remembered by using “Can i keep selling shoes for money, officer?”

  41. hey thanks for the mnemonics on both articles. I this one may be better than the one in my article.

  42. Thanks a lot. i am assured of success in my Biochemistry exam next week.

  43. Gary Silversmith lawsuit

    I’m really enjoying the design and layout of your site. It’s a very easy on the eyes which makes it much
    more enjoyable for me to come here and visit more often.
    Did you hire out a developer to create your theme?
    Outstanding work!

  44. Thank you for this post; I can draw the Krebs cycle from memory now!

  45. No problem! I’m glad this method could help you with the Krebs Cycle.

  46. U R the Best! Total ready for krebbbbsss question now.

  47. Thank you so much for you appreciation!!!

  48. it is a great post this make me enabled that i topped in my test . i hate cycles but this posts makes me like that now i love cycles. u r genious really. thank u sooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo much. plz also make others cycles like gluconeogenesis, glucogenesis and lipids,proteins fats metabolism cycles. plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz. and really thanks alot i will never 4gt these IN SHA ALLAH. 🙂 🙂 🙂