Metabolism Flashcards
What is potential energy?
Potential energy is the energy posessed by an object or person but isn’t currently being utilized.
What is kinetic energy?
The amount of kinetic energy an object has is due to movement. Water flowing down a cliff has kinetic energy.
What is activation energy?
Activation energy is the energy required for a reaction to occur and is at it’s lower when the reaction is catalyzed.
What is an exergonic reaction?
A exergonic reaction proceeds with a net release of energy and is spontaneous.
What is an endergonic reaction?
An endergonic reaction absorbs free energy from its surroundings and is nonspontaneous
What is entropy?
Entropy is a measure of disorder in a system.
Gases have higher entropy the liquids and liquids have higher entropy then solids.
What is ATP?
ATP is the primary currency of energy for the cell.
It has an adenosine backbone with three phosphate groups attached.
Which of the following is true is (are) true for anabolic pathways?
A)They do not depend on enzymes.
B) They are unusually high spontaneous chemical reactions
C) They consume energy to build up polymers from monomers.
D)They release energy as they degrade polymers to monomers.
E)They consume energy to decrease the entropy of the organism and it’s enviroment
A) They do not depend on enzymes.
Whenever energy is transformed, there is always an increase in the:
entropy of the universe.
Which of the following statements is a logical consequence of the second law of thermodynamics?
Every chemical reaction must increase the total entropy of the universe.
Which reaction would decrease the entropy within a cell?
Anabolic reactions
Which of the following is an example of potential rather than kinetic energy?
A) the muscle contractions of a person mowing grass
B) water rushing over Niagara Falls
C) light flashes emitted by a firefly
D) a molecule of glucose
E) the flight of an insect foraging for food
D) A molecule of glucose
Which of the following is the smallest closed system? A) a cell B) an organism C) an ecosystem D) Earth E) the universe
E) The universe
The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?
A) ΔS is the change in enthalpy, a measure of randomness.
B) ΔH is the change in entropy, the energy available to do work.
C) ΔG is the change in free energy.
D) T is the temperature in degrees Celsius.
C) ΔG is the change in free energy.
Which of the following is true for all exergonic reactions?
A) The products have more total energy than the reactants.
B) The reaction proceeds with a net release of free energy.
C) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.
D) A net input of energy from the surroundings is required for the reactions to proceed.
E) The reactions are rapid.
B) The reaction proceeds with a net release of free energy.
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell?
The phosphate may be incorporated into any molecule that contains phosphate
Which of the following statements is true about enzyme-catalyzed reactions?
A) The reaction is faster than the same reaction in the absence of the enzyme.
B) The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme.
C) The reaction always goes in the direction toward chemical equilibrium.
D) Enzyme-catalyzed reactions require energy to activate the enzyme.
E) Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions.
The reaction is faster than the same reaction in the absence of the enzyme.
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the
reaction’s
activation energy.
Which of the following statements regarding enzymes is true?
A) Enzymes increase the rate of a reaction by making the reaction more exergonic.
B) Enzymes increase the rate of a reaction by lowering the activation energy barrier.
C) Enzymes increase the rate of a reaction by reducing the rate of reverse reactions.
D) Enzymes change the equilibrium point of the reactions they catalyze.
E) Enzymes make the rate of a reaction independent of substrate concentrations.
B) Enzymes increase the rate of a reaction by lowering the activation energy barrier.
The active site of an enzyme is the region that
is involved in the catalytic reaction of the enzyme.
According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?
A) The binding of the substrate depends on the shape of the active site.
B) Some enzymes change their structure when activators bind to the enzyme.
C) A competitive inhibitor can outcompete the substrate for the active site.
D) The binding of the substrate changes the shape of the enzyme’s active site.
E) The active site creates a microenvironment ideal for the reaction.
D) The binding of the substrate changes the shape of the enzyme’s active site.
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? A) denaturization of the enzyme B) allosteric inhibition C) competitive inhibition D) saturation of the enzyme activity E) insufficient cofactors
C) competitive inhibition
19) Which of the following is true of enzymes?
A) Nonprotein cofactors alter the substrate specificity of enzymes.
B) Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered.
C) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature.
D) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
E) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.
D) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
