Biochemistry Flashcards
What is the First Law of Thermodynamics?
Energy cannot be created or destroyed
What is the Second Law of Thermodynamics?
When energy is converted from one form to another, some of that energy becomes unavailable to do work
What is enthalpy?
Heat content (H)
What is entropy?
Disorder (S)
What is an exergonic reaction?
One in which the total free energy of the products is less than the total free energy of the reactants
DeltaG negative
Spontaneous
What is an endergonic reaction?
One in which the total free energy of the products is greater than the total free energy of the reactants
DeltaG positive
Cannot occur spontaneously
What is Vmax?
The maximal velocity of an enzyme
What is Km?
The substrate concentration where the initial reaction is half-maximal
When 1/[V] is plotted against 1/[S], what is Vmax?
The intersection of the straight line with the y-axis
When 1/[V] is plotted against 1/[S], what is Km?
The intersection with the X axis
When a competitive inhibitor is added what happens to the plot of 1/[V] against 1/[S]?
Vmax does not change but Km varies
The y-intercept stays the same but the x-intercept varies
When a non-competitive inhibitor is added what happens to the plot of 1/[V] against 1/[S]?
Vmax decreases but Km stays the same
The y-intercept increases but the x-intercept stays the same
Is the anabolism oxidation or reduction?
Reduction
Is catabolism oxidation or reduction?
Oxidation
Name the 3 fates of glucose
Ribose-5-phosphate
Lactate
Pyruvate
Describe glycolysis
glucose –> fructose-1,6-bisphosphate –> 2 triose phosphates –> 2 pyruvate
Net gain 2 ATP and 2NADH
Name the 3 enzymes which control glycolysis and what their function is
Hexokinase - substrate entry
Phosphofructokinase - rate of flow
Pyruvate kinase - product exit
How is pyruvate metabolised to acetyl-coA?
Pyruvate dehydrogenase complex (PDC)
Where are the enzymes of the TCA cycle located?
In the mitochondria
What does each turn of the TCA cycle require?
Uptake of acetyl-coA
What does each turn of the TCA cycle produce?
2 CO2
2 NADH
1 FADH2
How is ATP produced in oxidative phosphorylation?
Energy from electrons are used to pump protons from the mitochondrial matrix to the intermembrane space
Protons flow back into the mitochondrial matrix via ATPase, producing ATP
How is NADH from the cytoplasm transported into the mitochondria?
The malate-aspartate shuttle
