Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
62 Cards in this Set
- Front
- Back
What is the formula for the pyruvate dehydrogenase reaction? |
pyruvate + CoA + NAD+ ---> acetyl-CoA + CO2 + NADH |
|
How many enzymes are used to form the pyruvate dehydrogenase complex? |
Three: E1, E2, and E3 |
|
How is acetyl-CoA generated? |
From the catabolism of other biomolecules |
|
What three other ways can the catabolism of other biomolecules generate acetyl-CoA? |
1. Proteins --> amino acids --> acetyl-CoA 2. Polysaccharides --> monosaccharides --> acetyl-CoA 3. Fats --> fatty acids --> acetyl-CoA |
|
How many reactions can be associated with the citric acid cycle? |
Eight |
|
What is the first reaction of the citric acid cycle? |
Citrate synthase adds an acetyl group to oxaloacetate |
|
What occurs in the first reaction of the citric acid cycle? |
Oxaloacetate and acetyl-CoA undergo citrate synthase to form citrate |
|
What goes into and comes out of citrate synthase in the first step of the citric acid cycle? |
H2O ---> HSCoA |
|
When does citrate synthase undergo a conformational change? |
Upon binding to oxaloacetate, allowing the binding of acetyl-CoA |
|
What is the second reaction of the citric acid cycle? |
Aconitase isomerizes citrate to isocitrate |
|
What formations occur in the second reaction of the citric acid cycle? |
Citrate <---> Aconitate <---> Isocitrate |
|
What is put into the reactions for the second reaction of the citric acid cycle? |
H2O for either reaction |
|
What is the third reaction of the citric acid cycle? |
Isocitrate dehydrogenase releases the first CO2 |
|
What occurs during the third reaction of the citric acid cycle? |
Isocitrate reacts to form alpha - ketogluterate |
|
What goes into and comes out of the third reaction of the citric acid cycle? |
NAD+ goes in and H+ and NADH come out then the first CO2 comes out then H+ is put in |
|
What is the forth reaction of the citric acid cycle? |
Alpha - ketogluterate dehydrogenase releases the second CO2 |
|
What occurs in the forth reaction of the citric acid cycle? |
Alpha - ketogluterate reacts to form succinyl CoA |
|
What goes into and comes out of the forth reaction of the citric acid cycle? |
CoASH goes in and CO2 comes out NAD+ goes in and NADH comes out |
|
Where did the two carbons released in the 1st round of the citric acid cycle not come from? |
Acetyl-CoA |
|
In what reactions are the two carbons released in the citric acid cycle? |
Reactions 3 and 4 |
|
In what form are the carbons in the citric acid cycled released? |
CO2 |
|
What is the fifth reaction of the citric acid cycle? |
Succinyl-CoA synthetase catalyzes substrate level phosphorylation |
|
What occurs during the fifth reaction of the citric acid cycle? |
Succinyl-CoA undergoes succinyl-CoA synthetase to form succinate |
|
What goes into and comes out of the fifth reaction of the citric acid cycle? |
GDP and Pi go in and GTP and CoA-SH come out |
|
What is the sixth reaction of the citric acid cycle? |
Succinate dehydrogenase generates ubiquinol |
|
What occurs during the sixth reaction of the citric acid cycle? |
Succinate undergoes succinate dehydrogenase to form fumarate |
|
What goes into and comes out of the sixth reaction of the citric acid cycle? |
Enz-FAD goes in and Enz-FADH2 comes out |
|
What occurs in the sixth reaction of the citric acid cycle in order for Enzyme-FAD to go in and Enzyme-FADH2 to come out? |
Q must go in and QH2 comes out |
|
T or F: The transformation of Enz-FAD to Enzy-FADH2 is a one way path. |
False |
|
What is the seventh reaction of the citric acid cycle? |
Fumerase catalyzes a hydration reaction |
|
What occurs during the seventh reaction of the citric acid cycle? |
Fumarate undergoes fumarase to form malate |
|
What goes into the seventh reaction of the citric acid cycle? |
H2O |
|
What is the eighth reaction of the citric acid cycle? |
Malate dehydrogenase regenerates oxaloacetate |
|
What occurs during the eighth reaction of the citric acid cycle? |
Malate undergoes malate dehydrogenate to form oxaloacetate |
|
What goes into and comes out of the eighth reaction of the citric acid cycle? |
NAD+ goes in and NADH+ and H+ comes out |
|
Where does regulation occur in the citric acid cycle? |
At the three irreversible steps |
|
What are the three irreversible reactions of the citric acid cycle? |
Reaction 1, reaction 3, and reaction 4 |
|
What type of cycle is the citric acid cycle? |
An Energy-Generating cycle |
|
What comes out of the reaction of glucose to pyruvate? |
2 NADH = 5 ATP 2 ATP Total: 7 ATP |
|
What comes out of the reaction of pyruvate to acetyl-CoA? |
2 NADH = 5 ATP Total: 5 ATP |
|
What comes out of the citric acid cycle? |
6 NADH = 15 ATP 2 QH2 = 3 ATP 2 GTP 2 CO2 Total: 18 ATP + 2 GTP + 2 CO2 |
|
T or F: The intermediates of the citric acid cycles are precursors of other molecules |
True |
|
What is an example of an amino acid formation from a citric acid cycle intermediate? |
Alpha-ketogluterate and NH4+ undergoes glutamate dehydrogenase to form glutamate |
|
T or F: Intermediates that are diverted to other pathways cannot by replenished |
False |
|
What can replenish citric acid cycle intermediates? |
Anaplerotic reactions |
|
What can occur to some pyruvate during exercise? |
Some pyruvate can be converted to an alpha-ketoglutarate to boost the activity of the citric acid cycle |
|
Which TCA cycle intermediate is found at both the beginning and end of the citric acid cycle? |
Oxaloacetate |
|
How many NADH are produced when one acetyl group is oxidized in the TCA cycle? |
Three |
|
Citrate synthase binds which substrate first? |
Oxaloacetate |
|
T or F: The two carbon atoms that enter the TCA cycle as acetyl-CoA are released as two CO2 molecules in the same round of the citric acid cycle |
False |
|
What can dispose of carbon atoms through the TCA cycle? |
Carbohydrates, fatty acids, and amino acids |
|
Flux through the TCA cycle is regulated at the __________ steps. |
Irrevirsible |
|
During oxidation of acetyl-CoA through the TCA cycle, which steps involve oxidative decarboxylations? |
Steps three and four of TCA cycle |
|
Which enzymes of the TCA cycle contain an FAD cofactor? |
Succinate dehydrogenase |
|
How many NADH are oxidized in one turn of the TCA cycle? |
Zero |
|
Which reactions in the TCA cycle release CO2? |
Steps three and four |
|
Which reaction in the TCA cycle directly generates a GTP? |
Step 5 |
|
Which reaction in the TCA cycle gives electrons too ubiquinone? |
Step six |
|
Malonate is a competitive inhibitor of succinate dehydrogenase. What TCA intermediates accumulate if malonate is present in the preparation of isolated mitochondria? |
Succinate, succinyl-CoA, and alpha-ketoglutarate |
|
Oxaloacetate is labeled with 14C at the C4 carbon. In which step of the TCA cycle will the label be lost as 14CO2? |
Alpha-ketoglutarate dehydrogenase reaction |
|
Acetyl-CoA is labeled with 14C at the C1 carbon and enters the TCA cycle. In which round of the cycle will the label be lost as 14CO2? |
The second round |
|
Citrate, the produce of step one of the TCA cycle, is an allosteric effector of phosphofructokinase. Would it be likely to activate or inhibit this enzyme? |
Inhibit |