Enzymes and Bioenergetics Flashcards
______ refers to the differences in potential energy of the substrate and products of a reaction. If the product has less potential energy than the substrate, the reaction is ______ _____.
Bioenergetics
Energetically favorable
_____ refers to the speed at which substrates are converted to products
Kinetics
_____ increase the sodas if reactions. They do not alter the energetic reactions
Enzymes
_______ = delta H - T deltaS
The change in free energy, delta G
If delta G is negative, the reaction will proceed _____ in the forward direction. If delta G is positive the reaction will proceed ______ in the reverse direction
Spontaneously
Spontaneously
Delta H is the heat exchange. If delta H >0, the reaction is ______. If delta H<0 the reaction is ______.
Endothermic
Exothermic
View the chart
In the _____ of fuels, electrons are transferred from CC bonds to redox intermediates such as ___ and ___. The electrons reduce molecule oxygen to water in the ___ ____ ____.
Oxidation
FAD
NAD+
Electron transport chain
The oxidation of fuels is a _____ reaction.
Exergonic
The conversion of glucose __ phosphate to glucose ___ phosphate is a key step to synthesizing glycogen (how we store glucose).
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1
______ catalyzes the intercom version between glucose 1phosphate and glucose 6phosphate.
Phosphoglucomutase
Un favorable energetics can be over come by manipulating the substrate and product concentrations. Often times the product will be used as _____ in the subsequent reactions that have _____ free energy changes.
Substrates
Negative
The enzyme ______ uses ATP in the first step of glycolysis to add phosphate to the 6 carbon of glucose.
Hexokinase
binding of ______ at the hexokinase active site creates a binding site for ATP
D glucose
The enzyme hexokinase links the hydrolysis of ATP to the phosphorylation of glucose in an energetically _____ reaction.
Favorable
What is the name of this reaction?
What does it represent ?
Michaelis-Menten equation
The relationship between the rate of product formation and substrate concentration. It measures reaction rates (v).
There are different i so forms of hexokinase expressed in different tissue , for example _____ in the liver. Erythrocyte Hexokinase has a Km of 0.05 mM glucose. Glucokinase has a Km of 5.0 mM glucose. Compare the graph.
Glucokinase
Plotting the reciprocals of the initial velocity versus the substrate concentration results in _____ ____. This is the Lineweaver Burk transformation.
Linear plots
Plotting the reciprocals of the initial velocity versus the substrate concentration results in _____ ____. This is the Lineweaver Burk transformation.
Linear plots
_____ ____ bind enzymes at the same site as a substrate. As the substrate concentration increases, it outcompetes the competitor. They do not change the _____, they increase the _____ because the concentration of substrate requires increases.
Competitive inhibitors
Vmax
Km
A _____ _____ blocks the reaction without competing for the substrate binding site, for example they bind make a covalent bond to the enzyme which inactivates it. They decrease ____ but the ____ remains the same.
Non competitive inhibitors
Vmax
Km
____ inhibitors/activators bind at sites away from the active site and alter the enzymes activity. They do not follow strict Michaelis-menten kinetics.
Allosteric
For allosteric enzymes, their plot is _____ rather than hyperbolic. Activators make the curve more _____. Inhibitors make the curve more ______.
Sigmoidal
Hyperbolic
Sigmoidal
_____ _____ is when the inhibitor only binds after the substrate has binded. The decrease ____ and _____. An example is phenylalanines inhibition of alkaline phosphatase
Uncompetitive
Km
Vmax
What is this graph showing
A competitive inhibitor because Km is changing, but Vmax is staying the same
What is this graph showing
Non competitive inhibitor, the Vmax is decreasing, Km is staying the same
What is this graph showing
Uncompetitive inhibitor
Glucose ___ phosphate is more favorable than glucose ___ phosphate in the body
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1
What is this graph showing
Allosteric regulation
Both reactions
Accumulation of fructose 1,6 bis phosphate
Red blood cells
Activator
Cysteine is a competitive inhibitor
Km is the substrate concentration at which the rate of product formation is one half of ____.
Velocity
J
K
