Energy & Reactions
Enzyme Function
Enzyme Structure
Enzymes & Metabolism
FINAL JEOPARDY!
100
What is the difference between kinetic energy and potential energy?
Kinetic energy is the energy of motion, while potential energy is energy stored in position or configuration.
100
A lactase enzyme catalyzes the decomposition of lactose. What happens to the enzyme when the reaction is done?
The enzyme is not changed.
100
Enzymes are biological ____ made out of ______ (which macromolecule).
Enzymes are biological catalysts made out of proteins.
100
What is the purpose of metabolic processes in the body?
Metabolic processes allow organisms to build and break down macromolecules.
200
What two main factors increase reaction rate? Why?
An increase in temperature or reactant concentration will increase reaction rate. This is because both of these increase the likelihood of collisions between particles.
200
Enzymes (speed up/slow down) reactions by (lowering/raising) the (Gibbs free energy/activation energy) of the reaction.
Enzymes speed up reactions by lowering the activation energy of the reaction.
200
What would happen if an enzyme that normally functioned at a pH of 7.4 was put into a solution with a pH of 3?
The enzyme would denature.
200
Substrates:
A -----------> B ----------> C ----------> D
enzyme 1 enzyme 2 enzyme 3
What are the B and C molecules referred to as?
Molecules B and C are called intermediates; they serve as both a product and a reactant.
300
Explain how ATP hydrolysis releases energy. How is this energy used in cells?
The phosphate groups of ATP are very high energy. When ATP is hydrolyzed, it forms ADP + inorganic phosphate. This releases a lot of energy (very exergonic). In cells, this energy can be used to power an endergonic reaction.
300
Explain the lock-and-key model.
Enzymes and their substrates have specific bonding; they fit together like a lock (the enzyme) and key (the substrate).
300
What is the difference between cofactors, coenzymes, and prosthetic groups?
Cofactors: inorganic ions that reversibly interact with enzymes
Coenzymes: organic molecules that reversibly interact with enzymes
Prosthetic groups: non-amino acid atoms or molecules permanently bonded to enzymes
300
Describe the process of feedback inhibition.
In feedback inhibition, the product of a metabolic pathway inhibits an enzyme earlier in the pathway.
400
What is Gibbs free energy (G)? What is a reaction with negative G called? What is a reaction with positive G called? What about zero G?
Gibbs free energy is the amount of energy in a reaction available to do work. A reaction with negative G is exergonic and spontaneous. A reaction with positive G is endergonic and nonspontaneous. A reaction with 0 G is at equilibrium.
400
What happens at the saturation point of enzyme-catalyzed reactions? How would the reaction rate increase?
At the saturation point, all available enzymes are working, so even if the concentration of the substrate increases, the rate of the reaction won’t increase. More enzymes would have to be added to increase the reaction rate.
400
What is the difference between competitive and allosteric inhibition of enzymes?
In competitive inhibition, a similarly-shaped molecule prevents the substrate from binding by binding to the active site. In allosteric inhibition, a regulatory molecule binds to the allosteric site of an enzyme, causing a shape change. Then, the original substrate is unable to bind to the enzyme.
400
What is the difference between catabolic and anabolic pathways?
Catabolic pathways break down molecules. Anabolic pathways synthesize molecules.
500
(CH2O)2H + 6O2 → 6CO2 + 6H2O + Energy
Which molecule is oxidized? Which is reduced?
The carbon of the glucose is oxidized and the oxygen is reduced. This is because electrons are pulled away from the carbon in CO2 and pulled towards the oxygen in H2O.
500
What is happening at the molecular level when an enzyme catalyzes a reaction?
At the molecular level, enzymes bond to the substrate (initiation). Then, the interactions between the enzyme and substrate lower the activation energy (transition state facilitation), perhaps stabilized by a shape change of the enzyme. Finally, the products are released due to a lower affinity for the active site (termination).
500
Label the parts of the enzyme.
500
What is bioremediation? How does it connect to metabolic pathways?
Some organisms have evolved to produce enzymes that can break down human-made chemicals. Bioremediation is the use of these enzymes to clean up human-made pollutants.
500
A person with lactose intolerance is not able to process lactose. The lactaid supplement allows people with lactose intolerance to eat dairy products.
What could be the cause of lactose intolerance? How could lactaid help?
Lactose intolerance is caused by a lack of lactase, the enzyme that breaks down the lactose sugar. Lactaid provides lactase enzymes produced from bacteria or fungi.