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Prep-Step & Krebs Cycle of Cellular Respiration?
Can you help me improve my prep-step/krebs cycle (of cellular respiration) paragraph?
"Pyruvate enters the mitochondria. A carbon atom from the pyruvate acid becomes a molecule of carbon dioxide and is released into the air. The remaining two atoms join a coenzyme A to form acetyl CoA; then adds the two carbon acetyl group to a four carbon molecule making a six carbon molecule. A carbon molecule is removed from the citric acid and another is released which leaves a four carbon molecule. For each turn of the cycle, a molecule of ADP is converted into ATP because of ADP being phosphorylated to produce the ATP, and NAD+ and FAD are converted into NADH (because the enzyme transfers a hydrogen) and FADH2 (because the FAD accepts two hydrogen atoms). Then, the cycle happens once more."
If any of you can improve this or tell me what needs to be added (or removed), I would greatly appreciate it. :)
2 Answers
- Anonymous9 years agoFavorite Answer
hi, so to sum up stuff...pyruvate is oxidative decarboxylased by E1 (pyruvate dehydrogenase component with coupliing to TPP), this step produces CO2. Next the E1 component oxidizes pyruvate again producing 2 electrons, next the E2 component (dihydrolipoyl transacetylase) coupling with lipoamide, transfers the acetyl group to the CoA. An E3 component is used to regenerate the lipoaminde used in E2. the Coa binds with the oxaloacetate forming a 6 C molecule this molecule is decarboxylased twice producing two CO2, 1 GTP, and 8 electrons. Now the cycle is complete and you have a 4 C molecule again-oxaloacetate. the CAC produces 3 NADH, 1 GTP, 2 CO2, 1 FADH2. Pyruvate is also used in anaerobic fermentation to regenerate FAD+ for the use in CAC.. Yes, remember that all this happens twice because two pyruvates are produced...
i have alot more info bout it lol i have exam tomorrow on glycolysis CAC and gluconeogenesis!!
does this help?
Source(s): biochem class...:) - Anonymous5 years ago
You breath to obtain oxygen and off load CO2. During cellular respiration pyruvate enters the mitochondrion (pyruvate is the end result of glycolysis) through pores. It then undergoes a chain of reactions called the Krebs (or citric acid) cycle. In this process electrons are taken from a higher energy state to a lower energy state. They are passed along molecules that take them into the mitochondrial membrane. This pulls protons with it. This is the electron transport chain. Now there is a concentration gradient of protons that will pass through the membrane and back into the mitochondrial matrix butv first will pass through a molecule call ATP synthase. When they pass through this enzyme it spins and this action generates ATP. The only thing left to do is get rid of those electrons. Oxygen is reduced (it accpets electrons) at this point. Remember that Oxygen is highly electronegatiove and readily accepts these electrons. This is called oxidative phosphorylation and is the sole reason why we breath. The short answer is that cellular repiration generates ATP from the breakdown of sugar. Breathing introduces the final electron acceptor, Oxygen. With the exception of glycolosis (that occurs in the cytoplasm) this all takes place in the mitochondrion.