Lecture 22- Citric Acid Cycle
Memorize all the intermediates in the Citric Acid cycle and the number of carbons in each?
Acetyl-CoA (2 carbon), Citrate (6c), Isocitrate (6c), Alpha Ketoglytarste (5c). Succinyl, Succinate, Fumarate, Malate, and Oxaloacetate are all 4 carbon.
How many reduced cofactors are produced in the citric acid cycle per glucose? What is their fate?
Each cycle produces 3 NADH, 1 FADH2, 2 CO2, 1 CoA, and one ATP. The pyruvate transport stage produces one Acetyl CoA, 1 NADH and 1 CO2 for each pyruvate. Glucose becomes 2 pyruvates so for one glucose we do each process twice and get twice the products. From what we know so far, the NADH and FADH2 go on to the electron transport chain, the CO2 exhaled, ATP is used to do work and CoA is recycled back into the Citric Acid cycle.
What is FAD? Is this the reduced or oxidized form? What step is it used at during Citric Acid cycle.
Flavin adenine dinucleotide, or FAD, is an oxidized form of an electron carrier that accepts electrons during the Krebs Cycle.
Where do these molecules enter the Krebs cycle and what has to happen to them first?
Proteins enter at Alpha Keto Glutamate and the Glutamate as to be converted to that through the removal of the NH3 and being replaced by a carbonyl group. Fats are broken down into Acetyl-CoA and enter at the very beginning.
What happens to pyruvate as it enters into Mitochondria? Name products/coenzymes of this reaction if any.
Pyruvate turns in Acetyl-CoA (A 2 Carbon) by adding NAD and CoA, this releases NADH and CO2 as a result Then Acetyl CoA (2c) goes in the citric acid cycle in the mitochondia and is binded with Oxacoacetate (4c) to make Citrate (6c)
How many ATP are made during the citric acid cycle? There are actually 2 intermediate steps in the formation of ATP from Succinylcholine-CoA. What are these intermediate steps.
The intermediate steps P+ GDP. GDP to make GTP then to ATP. I think the two steps are the phosphate which will replace coenzyme A. Then the inorganic phosphate will be donated to GDP to produce GTP which is then converted to ATP.
The Citric Acid cycle itself can be divided into three stages called Pyruvate transport, CO2 emission stage and the oxaloacetate reformation stage. Where would you draw the line dividing the three stages and why?
The line between the pyruvate transport and the CO2 emission step is when pyruvate is made into Acetyl-CoA. The line between the CO2 emission and the oxaloacetate reformation stage is when Succinyl-CoA is changed into Succinate. There are distinct lines between the stages and it isn't hard to locate them.
What are the products of Citric Acid cycle and where are they given off?
The products of the citric acid cycle are: 3 NADH's, 1 FADH2, and 1 ATP. The Krebs cycle occur in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis. Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2 carbon molecule.
How many ATP are produced from one pyruvate that enters Citric Acid cycle. How many per glucose?
There is one molecule of ATP produced from one pyruvate that enters the Citric Acid. No ATP is consumed in this cycle. There are 2 molecules of ATP made per glucose that enter the glycolysis reaction. So far there isn't much ATP produced in this system, but I imagine there are steps and reactions coming that produce a ton of ATP.
What is the reaction step and how are the two similar? Talking about the breakdown of pyruvate
This takes place in the transformation of Succinyl-CoA to succinate. ADP and Pi are brought together to form ATP and CoA is removed.
Which so we do first, produce CO2 or consume O2? Use the process of cellular respiration to defend your answer.
We take in O2, mostly because it is necessary for us to live and survive. Think about taking hike on Mount Everest. The higher you go, the less oxygen there exists and the less compatible your body is able to carry out cellular respiration to produce CO2 and keep the Cycle going.
