ETC Flashcards
Which enzyme from the TCA cycle is involved in the ETC?
Succinyl dehydrogenase
What are the roles of ATP?
-serves as a mediator of biological energy transfer
-Links the energy yielding, exergonic processes and the energy- requiring endergonic processes so that they occur spontaneously.
-represents stored form of energy in the cells
What is enthalpy and change in enthalpy?
Heat content of physical object or system
Change in enthalpy (∆H)-heat absorbed or released during a reaction
What is entropy and change in entropy?
Randomness or disorder of a system.
Change in entropy (∆S) degree of randomness created during reaction
What is free energy and change in free energy?
Energy available for doing work in a system
∆G-change in free energy occurring during biological reactions.
∆G=∆H-T∆S
Are exergonic reactions negative or positive?
Negative
Are endergonic reactions negative or positive?
Positive
A chemical reaction can occur spontaneously if they are accompanied by a____ in free energy (∆G)
Decrease
When ∆G becomes ____ (∆G=0) the reaction is at ____
Zero and equilibrium
The reaction is said to be exergonic if there is a ____ of Free energy (∆G)
loss
The reaction is said to be endergonic if the energy has to be ______ to the reactants
Supplied
Which reaction occurs spontaneously and which reaction doesn’t?
Spontaneously: Exergonic
Non-spontaneous: Endergonic
If the ∆G of the forward reaction (A to B) is _____ (negative), then the ∆G of backward reaction (B to A) is ______ (positive)
Exergonic, endergonic
At equilibrium, ∆𝐺 is zero when forward reaction = _____
backward
Hydrolysis is an example of what (give an example)
Exergonic reaction
ATP–> ADP + Pi
If the ∆G of a reaction is zero:
a) The reaction is irreversible
b) The reaction is endergonic
c) The reaction is exergonic
d) The reaction is at equilibrium
D
Consider the reactions of a biochemical pathway given below. What is the ∆G of the overall reaction conversion of A to D?
A–> B–> C–> D
A–> B delta G= -12.3 kcal/mol
B–> C delta G= 8.4 kcal/mol
C–> D delta G= -5.6 kcal/mol
9.6 kcal/mol
Where is the ETC located?
Inner mitochondrial membrane
Sources that generate FADH2
TCA cycle → Succinate dehydrogenase
β- oxidation of fatty acids → Acyl CoA dehydrogenase
Sources that generate NADH
Glycolysis: Glyceraldehyde-3-phosphate dehydrogenase
Pyruvate dehydrogenase
TCA cycle: Isocitrate dehydrogenase, α-Ketoglutarate dehydrogenase, Malate dehydrogenase
β-Oxidation: β-hydroxyacyl CoA dehydrogenase
How does NADH enter the mitocondria?
Malate-aspartate shuttle
Glycerol-3-phosphate shuttle
Where does the malate-aspartate shuttle take place?
Liver and heart muscles
How much ATP is yielded from the malate-aspartate shuttle ?
3
Where does the glycerol-3-phosphate shuttle take place?
Brain and skeletal muscle
