Krebs Cylcle Trick How to remember krebs cycle FOREVER!!

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KREBS CYCLE (called after Hans Krebs) is a part of cellular respiration. Its other names are the citric acid cycle, and the tricarboxylic acid cycle (TCA cycle).
It is the series of chemical reactions used by all aerobic organisms to generate energy. It is important to many biochemical pathways. This suggests that it was one of the earliest parts of cellular metabolism to evolve.

The Krebs cycle comes after the link reaction and provides the hydrogen and electrons needed for the electron transport chain. It takes place inside mitochondria.

The TCA cycle plays a central role in the breakdown, or catabolism, of organic fuel molecules—i.e., glucose and some other sugars, fatty acids, and some amino acids. Before these rather large molecules can enter the TCA cycle they must be degraded into a two-carbon compound called acetyl coenzyme A (acetyl CoA). Once fed into the TCA cycle, acetyl CoA is converted into carbon dioxide and energy.

The TCA cycle consists of eight steps catalyzed by eight different enzymes (see Figure). The cycle is initiated when acetyl CoA reacts with the compound oxaloacetate to form citrate and to release coenzyme A (CoA-SH). Then, in a succession of reactions, (2) citrate is rearranged to form isocitrate; isocitrate loses a molecule of carbon dioxide and then undergoes oxidation to form alpha-ketoglutarate; alpha-ketoglutarate loses a molecule of carbon dioxide and is oxidized to form succinyl CoA; succinyl CoA is enzymatically converted to succinate; succinate is oxidized to fumarate; fumarate is hydrated to produce malate; and, to end the cycle, malate is oxidized to oxaloacetate. Each complete turn of the cycle results in the regeneration of oxaloacetate and the formation of two molecules of carbon dioxide.

Energy is produced in a number of steps in this cycle of reactions. In step 5, one molecule of adenosine triphosphate (ATP), the molecule that powers most cellular functions, is produced. Most of the energy obtained from the TCA cycle, however, is captured by the compounds nicotinamide adenine dinucleotide (NAD+) and flavin adenine dinucleotide (FAD) and converted later to ATP. Energy transfers occur through the relay of electrons from one substance to another, a process carried out through the chemical reactions known as oxidation and reduction, or redox reactions. (Oxidation involves the loss of electrons from a substance and reduction the addition of electrons.) For each turn of the TCA cycle, three molecules of NAD+ are reduced to NADH and one molecule of FAD is reduced to FADH2. These molecules then transfer their energy to the electron transport chain, a pathway that is part of the third stage of cellular respiration. The electron transport chain in turn releases energy so that it can be converted to ATP through the process of oxidative phosphorylation.

The German-born British biochemist Sir Hans Adolf Krebs proposed this cycle, which he called the citric acid cycle, in 1937. For his work he received the 1953 Nobel Prize in Physiology or Medicine. Although Krebs elucidated most of the reactions in this pathway, there were some gaps in his design. The discovery of coenzyme A in 1945 by Fritz Lipmann and Nathan Kaplan allowed researchers to work out the cycle of reactions as it is known today.
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i missed my lectures and everybody said that i will never understand krebs cycle and then i found this video and now i know more than them...

AstroDeeptej
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I've ditched all my lecture notes as they make no sense, my tutors at University do not know how to teach things in a way I can understand. This YouTube channel is an absolute Godsend, whoever creates the content for this channel is a genius!! Thankyou so much for helping me through my Biomed degree!!

heatherstone
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7 minutes of your video explained this better than a textbook, a PowerPoint, and a 90 min lecture on the subject. Thank you SO much!

michaeladenning
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good stuff!

Also note: if you compare the two mnemonics side-by-side and skip Aconitase, every enzyme lines up with the intermediate it is named for.

C | S : Citrate Synthase
_ | A : Aconitase
I | D, : Isocitrate Dehydrogenase
K | D : alpha-Ketoglutarate Dehydrogenase
S | S : Succinyl CoA Synthase
S | D : Succinate Dehydrogenase
F | F : Fumarase
M, | D! : Malate Dehydrogenase
O? | _ :

samuelleingang
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I changed the second one to "SAD Devil Sipping Down Five Drinks" made more sense to combine first 3 letters together. Thanks for the video !!

magedgeorge
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“Can I Keep Selling Substances For Money Officer” helped me totally answer a question on a test today! 👍🏻 thanks!

rainbowcowpig
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I've spent the last 2 hours watching lectures trying to understand what you just said in 5 minutes. Thank you for your videos!!

bettinalasavio
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I was struggling for the longest time to understand the Krebs cycle and this video just made it all crystal clear. Thank you!!

ashleycruz
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I have a test this morning, Krebs cycle has been a big thing to me but you made it easy

You saved me, thank you🙏

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saniyasheikh
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The use of mnemonic aids is very helpful. Dr. Krebs has always been one of my Science heroes. I'll recommend your video to students. Thanks.

sherylmccoy
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I have an exam in 6 days and so far nothing has helped me. Thank you so much for making this vid, you are a life saver!

tremeramcbean
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I'm learning this right now to prepare for my PCAT and it looked terrifying at first but because of you MEDSimplified I feel like I can memorize it. Thank you and God bless please continue to help future students ♥

CianiaKim
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watched this video for my IB exams 2 years ago now I'm back from my biochem lectures and you just never seem to fail in explaining this so simply!!!!

veronaodhiambo
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The enzyme that converts succinyl-CoA to succinate is succinyl-CoA synthetase, not succinyl-CoA synthase. Synthetase means that ATP is generated

SummyCinTa
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"Can I keep selling substances for money, officer?"
"So at disco, devil sipped down five drinks!"

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