Enzymes
Factors Affecting Enzymes
Gibbs Free Energy Info
ATP
Metabolism
100
The site on the enzyme where the reactants bond to participate in a chemical reaction.
the active site
100
An enzyme alters a chemical reaction in what 2 ways?
- lowers the activation energy needed for the reaction
- speeds up the rate of the chemical reaction
100
These reactions consume energy to build up polymers from monomers.
anabolic reactions
100
ATP stands for
adenosine triphosphate
100
Whenever energy is transformed, there is always an increase in the
the entropy of the universe
200
This action occurs when an enzyme slightly changes shape when it bonds to the substrate in order to create the best chemical reaction possible.
induced fit
200
What occurs when an enzyme becomes denatured?
2 answers required
its unravels - bonds break apart
no longer functions properly
200
These reactions release energy to break down polymers into monomers.
catabolic reactions
200
This bond is the most energetic in the ATP molecule.
the bond between 2nd and 3rd phosphate or the terminal phosphate bond
200
A molecule of glucose represents what type of energy?
chemical potential energy
300
Which of the following terms best describes the forward reaction in Figure 8.1?
2 answers: exergonic v endergonic
&
∆G < 0 or ∆G > 0
exergonic, ∆G < 0
300
This type of inhibitor binds to the active site of the enzyme and block the active site so the substrate cannot bind and react.
competitive inhibitor
300
The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. What does each variable represent?
ΔG = free energy
ΔH = enthalpy - heat content
T = temperature
ΔS = entropy - disorder
300
When ATP is broken down to release energy, what type of chemical reaction must occur? What 2 molecules are involved in this type of chemical reaction?
- hydrolysis
- water & an enzyme
300
True or False: Metabolism consists of all the energy transformation reactions in an organism.
True
400
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?
a substrate
400
Which curve(s) on the graphs above may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?
curves 3 & 5
400
If ΔG = 0, what does that mean for the cell?
- there is no work being done bc there is no free energy to do work with
400
What is the term used to define what happens when the energy released from an exergonic reaction is then directly used to power an endergonic reaction?
energy coupling
400
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a _____________ needed to activate an enzyme.
cofactor
500
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. With respect to the enzyme that converts X to Y, substance A functions as...
an allosteric inhibitor
500
How can one overcome a competitive inhibitor in an enzymatic reaction?
add more substrate to the reaction
500
ΔG° = ΔH - TΔS °C = 5/9(F-32) K = °C + 273
Calculate the Gibbs free energy change (ΔG) for a reaction that occurs at 20°C, the change in heat (ΔH) = 19,070 cal, and the change in entropy (ΔS) = 90 cal/K.
ΔG = -7,300 cal
500
When you have a severe fever, what grave consequence may occur if the fever is not controlled?
change in the tertiary structure of your enzymes
500
Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?
the active site