Chapter: 9: prt: 1, 2, 3 Flashcards
What is the energy main currency for cells?
ATP
On ATP what bonds hold the most energy?
The Phospho-hydride bonds between the phosphate groups.
When ATP is hydrolyzed which phosphate group is broken?
the bond between the second and third phosphate group.
What is the result of ATP hydrolyzed reaction?
ATP + Water yields ADP + inorganic phosphate + 7.3 kcal/mol ATP
Oil Rig?
Oxidation it loses
Reduction it gains
For every reduction or oxidation there is an?
Oxidation or Reduction
Is an oxidation reaction
Is an reduction reaction
ENDERGONIC or EXERGOINIC?
- ) exergonic
2. )endergonic
Enthalpy looks at what?
Changes in potential energy
Entropy looks at what?
Changes in disorder
How reactions occur very efficiently?
- stepwise oxidation of sugar in cells
- small activation energies overcome by body temperature.
Some energy released during a carbon oxidation is temporarily blanked?
Captured
During a carbon oxidation reaction the energy temporarily captured in the form of high energy electrons is to ………?
Reduce NAD+ to NADH
Where does glycolysis take place?
Cytosol
What is glycolysis?
A series of enzymatically catalyzed reactions .
- That takes glucose as a precursor and turns it into two molecules of pyruvate.
in glycolysis, for every one mole of glucose there is how many moles of Pyruvate?
2
What happens to the carbons in pyruvate as opposed to the carbons in glucose? (glycolysis)
- They are oxidized in pyruvate
How many total reactions occur during glycolysis?
10
What is the energy-investment phase of glycolysis?
- The first half of the reactions in glycolysis
- Requires ATP to increase the potential energy of the early intermediates within these reactions.
How is ATP used in the beginning of glycolysis?
i.e step 1
- To convert glucose to glucose 6-phosphate the reaction stripes ATP of one of its phosphate groups. (step 1)
How is ATP used in the beginning of glycolysis?
i.e step 3?
- A different enzyme then step one catalyzes the reaction.
- By: hydrolyzing ATP and attaches it the phosphate group to in turn yield Fructose 1,6-biphospate
What is the key regulatory step in glycolysis?
step 3
What is the chemical equation for the energy-investment phase?
2 ATP yields 2ADP
What is the second half of glycolysis?
- Energy recovery phase: regain the ATP from the energy-investment phase. ( total of 4 ATP)
In the Energy recovery phase, how do we go from ADP to ATP?
- The phosphate bonded to the 1st carbon on the 1,3-Biphosphoglycerate is added back to ADP.
How are ATP made during glycolysis?
Substrate-level phosphorylation
What is the net gain/lose of ATP via glycolysis?
- net gain of 2 ATP molecules
When does substrate-level phosphorylation occur?
When an enzyme in its active site binds both to ADP molecule is bonded to an Phosphorylated substrate.
How is glycolysis regulated?
Feedback inhibition
When does Feedback inhibition occur?
When the product of some metabolic pathway acts allosteric inhibitor of an enzyme at an earlier step in that pathway.
Glycolysis is regulated by the feedback inhibition of blank as an allosteric inhibitor?
ATP
In glycolysis which step is the target for the feedback inhibition?
Step 3
What is the enzyme that mediates step three of glycolysis feedback inhibition?
phosphofructokinase
How many binding sites does phosphofructokinase have for ATP?
2
- an active site
- an allosteric binding site
How do the two binding sites for ATP differ on phosphofructokinase ?
- The active site has a much stronger affinity for ATP
What happens to the pyruvates following glycolysis?
- it exits the cytosol and enters the Mitochondria, crossing its double membrane and resides in the mitochondrial matrix.
Where do the Krebs cycle and pyruvate processing take place?
-mitochondrial matrix
What is pyruvate processing?
-You take 2 pyruvate (per glucose) and you yield Acetyl Co.
-
What are the differences in structure between Pyruvate and Acetyl CoA?
Pyruvate is a 3 carbon structure and Acetyl CoA is a 2 carbon structure.
What happens to the third carbon in pyruvate during the pyruvate processing?
- It is totally oxidized and forms into CO2
Where does some of the energy go to that was used to oxidize carbon in pyruvate processing?
- To NAD+ to form NADH.
2 Pyruvates per glucose yields what in pyruvate processing?
2 acetyl-CoA and 2 CO2
What is the process that completes the oxidation of the 2 acetyl-CoA and 2 C?
Krebs cycle
How many steps are in the Krebs cycle or the citric acid cycle?
- 8 steps.
T/F: in the Krebs cycle you end where you started?
True
At what step in the Krebs cycle is 1 of the carbons oxidized?
- Step 3
At what step in the Krebs cycle is 2 of the carbons oxidized?
- Step four
At what step in the Krebs cycle is there a substrate-level phosphorylation?
5
How many times does the Krebs cycle occur for each molecule of glucose?
Twice.
What is the difference between GTP and ATP
- it contains a guanine instead of an adenine
- Still had the high energy yielding bonds between phosphates.
How is the Citric Acid Cycle regulated?
- feedback inhibition by NADH and ATP.
- NADH and ATP (Allosteric inhibitors)
Following the Krebs cycle what remains?
6 fully oxidized carbons ( CO2)
4 ATP
10 NADH
2 FADH
t/f: each step in the citric acid cycle is catalyzed by a different enzyme?
True.
