The citric acid cycle (TCA: Trucarvixylic cycle)
14 important questions on The citric acid cycle (TCA: Trucarvixylic cycle)
What is pyruvate dehydrogenase (PDH)?
- Links glycolysis to the TCA cycle via pyruvate dehydrogenase complex
- reaction is irreversible (regulation)
- converts pyruvate to acetyl-CoA (oxidative decarboxylation, CO2 out!)
- Most important point since it is the entry of substrates into the TCA cycle
Where/When does the citric acid cycle/TCA happen?
- Mitochondira
- it is the final pathway of oxidation of fuels (carbohydrate, fatty acids, amino acids) which release stored energy
What is the overal reaction input/output?
- 1 Acetyl-CoA (C2)
output
- 3 NADH
- 1 FADH2
- 1 GTP
- (2 CO2)
- Higher grades + faster learning
- Never study anything twice
- 100% sure, 100% understanding
For my 1st exam I got a C. Then, I started looking for ways to learn better and I came across Study Smart. Since then I have scored a A+, A, A- and another A. I highly recommend it to everyone who wants to hear it. I am so happy with it!!
I was struggling to finish all my first-year subjects for 3 years. Then I discovered Study Smart, which helped me to finish all of them within 3 months.
Because of StudySmart, things are going well in many ways. Before, I always had study stress and no time for anything. Now I feel calm and confident (because of the program). I used to score a B, now I usually score an A or A+.
Hey Chris, I really want to thank you very much for developing the platform, I usually got around C for my exams, now I scored an A+, an A and a A- !!
Since using Study Smart, my average has increased significantly. I even completed a statistics course with a A+ while I'm bad at statistics. I took on extra courses this year, because of Study Smart. Thanks so much!
Ever since I started studying with StudySmart I passed all my exams !!! No more re-sits!! At first, I was happy with a pass and now I only get good grades. Many thanks!
I aced all the courses I studied with Study Smart. For law, I first scored a D, and now an A! I’m 100% sure that I’ll pass all the courses I study with Study Smart.
I always thought I studied well. My grades were fine. I could never have imagined that applying these study skills would have such a huge and direct impact on my grades, my speed and the pleasure I have in learning.
For the first time, I finally feel totally confident about the way I learn. I have the perfect overview and make great progress in terms of speed and the grades I get. Thanks, Chris!
I immediately started to enjoy learning again, and my grades soared. All of a sudden, everything went better. I highly recommend Study Smart to all students..
Being able to create my materials online made the process of studying so much smoother and quicker. I no longer have to spend a huge amount of my time on creating my summaries.
At first, my notes were a mess. Now I use Study Smart to take my notes in a perfectly structured way. It helps me to save a lot of time and do other things I enjoy.
Students that study with Study Smart get better grades. The system applies all the learning methods in such a way that both well-performing students and students who struggle perform much better.
Hi Chris, I would like to thank you very much. Last year I scored C on a course, and this year I got an A+ thanks to your method! Thank you very much!
The largest effect is that my child is more enthusiastic about school! Every parent wants their children to be happy at school, Study Smart made it happen.
In high school, I failed several exams, and that has really changed now. I actually needed this tool very much back then. Since I started studying with StudySmart, I haven't had any D's. My average score is now an A and those are results I would have never had in the past
With my old method, I passed only 3 out of 8 courses. Since I started taking my notes digitally in Study Smart, I have passed all my courses on the first try. For me, StudySmart takes away the stress of wondering if I will pass or not.
Thanks to StudySmart, I passed all my exams, and with better grades than before! On top of that, I have mastered a very good study method now, which I am confident will help me earn my degree.
What is the pathway to get ATP?
Glycolysis (aerobic), TCA cycle, beta-oxidation (fatty acids)
- Resulting in reduced co-enzymes (NADH, FADH2)
- Respiratory chain, ATP synthase (oxidative phosphorylation)
- uses O2
What is TCA cycle?
- Coupling to respiration
- is a series of oxidation/reductions
- oxidation of 1 Acetyl group (C2) to 2x CO2
- Harvesting "high-energy" electrons
- Which are used for ATP synthesis
Explain the anaerobic glycolysis, how is the TCA cycle involved in it?
- Coupling to Lactate dehydrogenase (LDH) where pyruvate is converted to lactate, where NAD+ produced by it is used to form ATP
Where in the TCA cycle does the condensation and the 2 oxidative decarboxylation take place?
- Acety-CoA to citrate citrate synthase
Oxidative decarboxylation (CO2 out!)
- Isocitrate to alfa-ketoglutarate Isocitrate dehydrogenase
- alfa-ketoglutarate to succinyl-CoA alfa-ketoglutarate dehydrogenase complex
What are the control points in TCA?
- Pyruvat dehydrogenase
inhibition: ATP, acetyl CoA, NADH
- activation: ADP, pyruvate
- Isocitrate dehydrogenase
- inhibition: ATP, NADH
- Activation: ADP
- alfa-ketoglutarate dehydrogenase
- inhibition: ATP, succinyl CoA, NADH
What an anapleurotic reaction?
- When one of the TCA cycle intermediates is added into the cycle that have been extracted from biosynthesis (E, in exemple)
- Pyruvate carboxylase could carboxylate pyruvate to oxaloacetate, giving the cycle more C4 compounds to condense with incoming C2 compounds
What is an catapleurotic reaction?
- When you use/steal C4 intermediates from the TCA for biosynthesis
- Aspartate biosynthesis also requires oxaloacetate, so when aspartate is synthesized the result is less net oxaloacetate. So when a catapleurotic reaction occur, there is less oxaloacetate to condens with acetyl CoA
- when there is not enough oxaloacetate, anapleurotic or filling-up reations are necessary
Which are the glucogenic amino acids forming oxaloacetate?
Which are the glucogenic amino acids forming Pyruvate?
- Alanine
- Cysteine
- Glycine
- Serine
- Threonine
- Tryptophan
Which are the glucogenic amino acids forming alfa-ketoglutarate?
- Arginine
- Glutamine
- Histidine
- Proline
Which are the glucogenic amino acids forming Succinyl CoA?
- Isoleucine
- Methionine
- Threonine
- Valine
Try our study magic for free
a PDF, study it super fast
- No sign up, email or credit card needed!
- AI makes unlimited flashcards
- Get unlimited quizzes and tests
- Ask AI anything
- No sign up, email or credit card needed!
- Have and keep perfect overview
- Make flashcards, notes and mind maps
- Review, test and score!
The question on the page originate from the summary of the following study material:
- A unique study and practice tool
- Never study anything twice again
- Get the grades you hope for
- 100% sure, 100% understanding
