Ls7a Week 3 Tuesday Chapter 6
Chemical energy
A form of potential energy held in the chemical bonds between pairs of atoms in a molecule.
substrate
A molecule acted upon by an enzyme.
enzyme
A protein that functions as a catalyst to accelerate the rate of a chemical reaction; enzymes are critical in determining which chemical reactions take place in a cell.
inhibitor
A synthesized compound that decreases the activity of an enzyme.
activator
A synthesized compound that increases the activity of an enzyme.
Which of the following is considered a form of kinetic energy? heat a rolling ball wind All of these choices are correct. light
All of these choices are correct.
Which of the following is TRUE of allosteric inhibitors of an enzyme? Allosteric inhibitors are structurally similar to the normal substrate of an enzyme. Allosteric inhibitors bind to the active site of the enzyme. Allosteric inhibitors decrease enzyme activity. Allosteric inhibitors increase the rate of enzyme activity. The effect of allosteric inhibitors can be reduced by adding more substrate.
Allosteric inhibitors decrease enzyme activity.
allosteric enzyme
An enzyme whose activity is affected by binding a molecule at a site other than the active site. Typically, allosteric enzymes change their shape on binding an activator or inhibitor.
Energy
Capacity to do work A property of objects that can be transferred from one object to another, and that cannot be created or destroyed
Which of the following statements violates the first law of thermodynamics? Cells make energy when they produce ATP. The conversion of energy from one form to another is 100% efficient. The universe contains a constant amount of energy. Endergonic reactions store energy.
Cells make energy when they produce ATP.
exergonic
Describes reactions with a negative ΔG that release energy and proceed spontaneously.
endergonic
Describes reactions with a positive ΔG that are not spontaneous and so require an input of energy
negative feedback
Describes the effect in which the final product of a biochemical pathway inhibits the first step; the process in which a stimulus acts on a sensor that communicates with an effector, producing a response that opposes the initial stimulus. Negative feedback is used to maintain steady conditions, or homeostasis.
Which of the following is TRUE about exergonic reactions? There is a positive ΔG. Energy is released from the reactants. The products of exergonic reactions have more free energy than the reactants.
Energy is released from the reactants.
Which of the following do enzymes change? ΔG; reaction rate; types of product generated; activation energy; the laws of thermodynamics
Enzymes increase the reaction rate and decrease the activation energy. The other parameters are not changed by enzymes.
How does increasing the temperature affect the change in free energy (ΔG) of a chemical reaction?
Increasing the temperature increases the value of TΔS, which decreases ΔG, since ΔG = ΔH - TΔS. As a result, an increase in temperature makes it more likely that a reaction will proceed without a net input of energy.
PE
Stored energy that is released by a change in an object's structure or position.
absolute temp T
Temperature measured on the Kelvin scale.
gibbs free energy
The amount of energy available to do work.
transition state
The brief time in a chemical reaction in which chemical bonds in the reactants are broken and new bonds in the product are formed.
Metabolism
The chemical reactions occurring within cells that convert molecules into other molecules and transfer energy in living organisms.
entropy
The degree of disorder in a system.
entropy (S)
The degree of disorder in a system.
energy coupling
The driving of a non-spontaneous reaction by a spontaneous reaction.
activation energy
The energy input necessary to reach the transition state.
KE
The energy of motion.
first law of thermodynamics
The law of conservation of energy: Energy can neither be created nor destroyed—it can only be transformed from one form into another.
ATP
The molecule that provides energy in a form that all cells can readily use to perform the work of the cell. ATP is the universal energy currency for all cells. Adenosine Triphosphate
active site
The portion of the enzyme that binds substrate and converts it to product.
second law of thermodynamics
The principle that the transformation of energy is associated with an increase in the degree of disorder in the universe.
Which of the following is true about spontaneous chemical reactions? The reactions have a positive change in free energy (+?G). They require ATP to go to completion. The reactions are exergonic.
The reactions are exergonic.
Catabolism
The set of chemical reactions that break down molecules into smaller units and, in the process, produces ATP to meet the energy needs of the cell.
Anabolism
The set of chemical reactions that build molecules from smaller units utilizing an input of energy, usually in the form of ATP. Anabolic reactions result in net energy storage within cells and the organism.
enthalpy (H)
The total amount of energy in a system.
In a reaction, enzymes change the: types of products. first law of thermodynamics. second law of thermodynamics. ΔG. activation energy.
activation energy.
You notice that a chemical reaction in your system is happening at a slow rate. You want to speed up the reaction. What do you do? add more products add an enzyme that catalyzes the reaction increase the activation energy change the ΔG for the reaction
add an enzyme that catalyzes the reaction
Which of the following describes ATP hydrolysis? (Select all that apply.) spontaneous often coupled to a reaction that has a positive ΔG exergonic
all of dem
Energy input in the form of ATP is needed in which of the following processes? anabolism catabolism
anabolism
Imagine that a bowling ball is placed at various locations along a staircase. At which location does the ball possess the GREATEST amount of potential energy? The ball will have the same amount of potential energy no matter where it is placed. at the top of the stairs in the middle of the staircase at the bottom of the stairs
at the top of the stairs
Anabolic pathways of metabolism are pathways that: make large quantities of ATP. take place primarily in skeletal muscle. build complex molecules from simple ones. release stored chemical energy.
build complex molecules from simple ones.
The first law of thermodynamics states that: there is an increase in disorder in the universe over time. only eukaryotic cells can produce ATP. combustion engines are 100% efficient. the universe becomes more orderly over time. energy cannot be created or destroyed.
energy cannot be created or destroyed.
A carbohydrate such as glucose has a great deal of _____ energy. heat work kinetic potential entropy
potential
Reactions in which there is a negative change in free energy (-ΔG) are: spontaneous and endergonic. spontaneous and exergonic. nonspontaneous and endergonic. nonspontaneous and exergonic.
spontaneous and exergonic.
Gibbs free energy is defined as: the amount of energy available to do work. the amount of entropy. the amount of energy lost as heat. the amount of potential energy in a system. spontaneous energy.
the amount of energy available to do work
The second law of thermodynamics states that: the universe becomes more orderly over time. there is an increase in disorder in the universe over time. energy cannot be created or destroyed. combustion engines are 100% efficient. only eukaryotic cells can produce ATP.
there is an increase in disorder in the universe over time.
What is the function of an enzyme? to decrease amount of energy needed to reach the transition state to increase the rate of a specific reaction to both increase the rate of a specific reaction and decrease the amount of energy needed to reach the transition state to alter the equilibrium of a specific reaction
to both increase the rate of a specific reaction and decrease the amount of energy needed to reach the transition state
The highest free energy is found in the _____(s) of a reaction. transition state substrate product
transition state
