SQ topic 8 Biol1009
When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, enthalpy and entropy are as follows: -)+∆H, -∆S, +∆G -)+∆H, +∆S, +∆G -)+∆H, +∆S, -∆G -)+∆H, -∆S, -∆G
-)+∆H, -∆S, +∆G
Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? -)+∆S, -∆G -)-∆S, -∆G -)-∆S, +∆G -)+∆S, +∆G
-)-∆S, +∆G
ATP is formed: -All of these answers are correct. -by many exergonic reactions -during many catabolic reactions -during hydrolysis of many biological polymers (e.g. carbohydrates, lipids and proteins)
-All of these answers are correct.
The ATP used by the cell for energy coupling: -has three phosphate groups. -All of these answers are correct. -is a high energy molecule due to having unstable covalent bonds -is identical to one of the four nucleotides used for RNA synthesis.
-All of these answers are correct.
Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics? -Living organisms create lots of entropy after they die and the molecules in their bodies dissociate, which makes up for the decrease in entropy created while they were alive. -As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. -As a consequence of growing, organisms create an amount of disorder in their environment that is equal to the decrease in entropy associated with their growth. -Living organisms do not follow the laws of thermodynamics.
-As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.
Anabolism results in the production of molecules with high amounts of potential energy stored in their chemical bonds. How can the reactions of anabolism occur without violating the requirement that all reactions must result in a decrease in free energy? -D) None of these answers are correct. -B) Energy from ATP is often used to help combine an exergonic reaction with a reaction that would otherwise be endergonic. -A) A reaction that would otherwise be endergonic is combined with an exergonic reaction. The overall reaction than occurs in multiple steps, each of which involves an exergonic reaction. -C) Both A and B are correct.
-C) Both A and B are correct.
Which of the following statements is representative of the second law of thermodynamics? -Cells require a constant input of energy to maintain their high level of organization. -Conversion of energy from one form to another is always accompanied by some gain of free energy. -Every energy transformation by a cell decreases the entropy of the universe. -Without an input of energy, organisms would tend toward decreasing entropy.
-Cells require a constant input of energy to maintain their high level of organization.
In a particular metabolic pathway, "A" is converted to "B" which is converted to "C". Which of the following is likely to be TRUE about catalysis of the steps in this pathway? -Each step in the pathway will likely be catalyzed by the same enzyme. -It is not possible to know without more information about "A", "B" and "C". -Each step in the pathway will likely be catalyzed by a different enzyme. -Some steps in the pathway may be catalyzed by the same enzyme and some steps may be catalyzed by different enzymes.
-Each step in the pathway will likely be catalyzed by a different enzyme.
Which of the following is a statement of the first law of thermodynamics? -The entropy of the universe is increasing. -The entropy of the universe is constant. -The entropy of the universe is decreasing -Energy cannot be created or destroyed
-Energy cannot be created or destroyed
Whenever energy is transformed, there is always an increase in the: -Free energy of the system -Entropy of the system -Entropy of the universe -Free energy of the universe
-Entropy of the universe
Many of the reactions that occur during metabolism are reversible. Given the laws of thermodynamics, how is that possible? -Even in the same solution, some of the molecules of a particular species may have more energy than others. -Energy is used to drive a reversible reaction in one of the two possible directions. -These reactions are reversible in theory, but proceed in only one direction so that the laws of thermodynamics are not violated. -The free energy of the system will decrease when the reaction proceeds in one direction, but the total energy of the system will decrease when the reaction proceeds in the other direction.
-Even in the same solution, some of the molecules of a particular species may have more energy than others.
Which of the following is a statement of the second law of thermodynamics? -Every energy transfer or transformation increases the entropy of the universe -Every energy transfer or transformation increases the free energy of the universe -Energy cannot be created or destroyed -Every energy transfer or transformation increases the enthalpy of the universe
-Every energy transfer or transformation increases the entropy of the universe
Which of the following statements is FALSE? -Phosphorylation of a molecule usually raises the potential energy of the molecule, making it more energetically favorable for that molecule to undergo spontaneous reactions. -Hydrolysis of ATP to form ADP and inorganic phosphate is a highly exergonic reaction -Hydrolysis of ATP to form ADP and inorganic phosphate is a highly endergonic reaction -Phosphorylation of a molecule usually makes the molecule less stable.
-Hydrolysis of ATP to form ADP and inorganic phosphate is a highly endergonic reaction
Which of the following is TRUE for ALL exergonic reactions? -If the reaction proceeds there will be a net decrease in free energy. -A net input of energy from the surroundings is required for the reactions to proceed. -The products have more total energy than the reactants. -The reactions are nonspontaneous.
-If the reaction proceeds there will be a net decrease in free energy.
When chemical, transport or mechanical work is done by an organism, what happens to the heat generated? -It is lost to the environment. -It is transported to specific organs such as the brain. -It is used to store more energy as ATP. -It is used to power yet more cellular work.
-It is lost to the environment.
Why is ATP an important molecule in metabolism? -It is formed by endergonic reactions. -All of these answers are correct. -It helps drive exergonic reactions. -It provides energy coupling between exergonic and endergonic reactions.
-It provides energy coupling between exergonic and endergonic reactions.
If most metabolic reactions are reversible, why is equilibrium rarely reached for these reactions? -The enzymes that catalyze these reactions drive the reactions more in one direction than in the other. -The activation energy barrier for the reaction is lower in one direction than in the other. -Because living organisms increase the entropy of the universe. -Most of the products of the reactions are removed from the system.
-Most of the products of the reactions are removed from the system.
If I try to hit a hockey puck, but miss and hit the ice instead, isn't that a violation of the first law of thermodynamics because my stick is no longer moving and neither is the puck? -A hockey game is a closed system. The first law of thermodynamics applies to the universe as a whole. -No, because the kinetic energy from the motion of my stick will have been transferred/transformed into increased heat energy in the ice. -None of these answers are correct. -This is a trick question since, of course, I NEVER miss the puck!
-No, because the kinetic energy from the motion of my stick will have been transferred/transformed into increased heat energy in the ice.
The mathematical expression for the change in the free energy of a system is ∆G = ∆H - T∆S. Which of the following is (are) TRUE? -T is the temperature in degrees Kelvin. -∆H is the change in free energy. -∆S is the change in enthalpy. -∆G is the change in entropy.
-T is the temperature in degrees Kelvin.
Which of the following is TRUE for all endergonic reactions in open systems (e.g. a cell)? -The products have less free energy than the reactants -The products have more free energy than the reactants -The products have more total energy than the reactants -The products have less total energy than the reactants
-The products have more free energy than the reactants
A reaction has a ∆G of -5.6 kcal/mol. Which of the following would most likely be TRUE? -The reaction would result in products with a greater free energy content than in the initial reactants. -The reaction would result in a decrease in entropy (S) and an increase in the energy content (H) of the system. -The reaction could be coupled to power an endergonic reaction with a ∆G of +8.8 kcal/mol. -The reaction would result in an increase in entropy (S) and a decrease in the energy content (H) of the system.
-The reaction would result in an increase in entropy (S) and a decrease in the energy content (H) of the system.
Which of the following statements about biological systems is FALSE? -The total energy in a biological system can increase -The entropy of a biological system can decrease -The total energy in a biological system can decrease -The total energy in a biological system cannot increase or decrease
-The total energy in a biological system cannot increase or decrease
What is the difference, if any, between the structure of ATP and the structure of the precursor of the A nucleotide in RNA? -There is no difference. -The number of phosphates is three instead of one. -The nitrogen-containing base is different. -The sugar molecule is different.
-There is no difference.
Which of the following statements concerning catabolic pathways is TRUE? -They combine molecules into more energy-rich foods. -They are spontaneous and do not need enzyme catalysis. -They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.
-They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.
Which of the following is (are) TRUE for anabolic pathways? -They do not depend on enzymes. -They are usually highly spontaneous chemical reactions. -They consume energy to build up polymers from monomers. -They release energy as they degrade polymers to monomers.
-They consume energy to build up polymers from monomers.
Living organisms don't violate the 2nd law of thermodynamics because: -Trick question, living organisms do violate the 2nd law of thermodynamics! -They typically increase their own entropy -They increase the free energy of their surroundings -They typically increase the entropy of their surroundings
-They typically increase the entropy of their surroundings
Which of the following is an example of potential rather than kinetic energy? -water flowing in a river -a food molecule -a hockey puck hitting the boards -an increase in air temperature as a meteor passes through the atmosphere
-a food molecule
At zero degrees Kelvin, in theory: -water will be frozen -you will be frozen -entropy will reach a minimum value -all of these answers are correct
-all of these answers are correct
The rate of flow of materials through a metabolic pathway can be altered by: -altering the amount of substrate for the reaction -all of these answers are correct -altering the amount of product for the reaction -changing the activity level(s) of one or more of the enzymes that catalyze steps in that pathway.
-all of these answers are correct
Which of the following is considered an open system? -a plant cell with a strong cell wall -an animal cell -a clam -all of these answers are correct
-all of these answers are correct
Which of the following is most similar in structure to ATP? -an amino acid with three phosphate groups attached -a DNA helix -an RNA nucleotide -an anabolic steroid
-an RNA nucleotide
Which of the following is considered an open system? -food cooking in a pressure cooker -an organism -a sealed terrarium -liquid in a corked bottle
-an organism
What is the term for metabolic pathways that release stored energy by breaking down complex molecules? -catabolic pathways -thermodynamic pathways -anabolic pathways -bioenergetic pathways
-catabolic pathways
The breakdown of polymers to their constituent monomers occurs during: -catabolism -condensation reactions -anabolism -dehydration reactions
-catabolism
Which term precisely describes the cellular process of breaking down large molecules into smaller ones? -catalysis -metabolism -anabolism -catabolism
-catabolism
Which of the following types of reactions would decrease the entropy of a cell? -catabolism -respiration -hydrolysis -dehydration reactions
-dehydration reactions
Spontaneous reactions: -all of these answers are correct -always proceed rapidly -do not require an energy input to occur -always occur, and do not require an energy input
-do not require an energy input to occur
A chemical reaction that has a positive ∆G is correctly described as: -endergonic -none of these answers are correct -spontaneous -exergonic
-endergonic
What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways? -cooperativity -energy coupling -feedback regulation -bioenergetics
-energy coupling
The total energy of a biological system is represented by: -free energy (G) -enthalpy (H) -temperature (T) -entropy (S)
-enthalpy (H)
The amount of energy in a system that is available to do work is represented by: -temperature (T) -free energy (G) -enthalpy (H) -entropy (S)
-free energy (G)
The hydrolysis of ATP to form ADP and Pi is: -highly endergonic -highly exergonic -slightly exergonic -slightly endergonic
-highly exergonic
Which of the following best describes enthalpy (H)? -the condition of a cell that is not able to react -the total kinetic energy of a system -in biological systems, enthalpy is equivalent to total energy -the system's entropy
-in biological systems, enthalpy is equivalent to total energy
Entropy: -is a measure of disorder or randomness -is a measure of the total energy of a system -is a measure of the energy in a system that is available to do work -is a measure of the total energy of a biological system
-is a measure of disorder or randomness
Free energy (G): -is a measure of the energy in a system that is available to do work -is a measure of the total energy of a system -is a measure of disorder or randomness -is a measure of the total energy of a biological system
-is a measure of the energy in a system that is available to do work
The statement "energy cannot be created or destroyed": -is a statement of the second law of thermodynamics -is true for closed and open systems, but not for the universe as a whole -is a statement of the first law of thermodynamics -is a statement of the third law of thermodynamics
-is a statement of the first law of thermodynamics
"Every energy transfer or transformation increases the entropy of the universe": -is true, except for living organisms -is a statement of the first law of thermodynamics -is a statement of the third law of thermodynamics -is a statement of the second law of thermodynamics
-is a statement of the second law of thermodynamics
Which of the following most accurately describe kinetic and potential energy? -kinetic energy includes energy from the attraction of the earth to the moon -potential energy includes energy from molecular movement -kinetic energy includes the energy in a stretched rubber band -kinetic energy is due to movement and potential energy is energy that is stored in matter that is not due to movement
-kinetic energy is due to movement and potential energy is energy that is stored in matter that is not due to movement
In an isolated system: -energy, but not matter, can leave the system. -neither energy nor matter can leave the system. -matter, but not energy, can leave the system. -heat, but not other forms of energy or matter, can leave the system.
-neither energy nor matter can leave the system.
Are most chemical reactions at equilibrium in living cells? -yes -no -most reactions, except those powered by ATP -only the exergonic reactions
-no
Energy that goes to increase the entropy of the universe is: -lost forever -all of these answers are correct -stored as potential energy -no longer available to perform work
-no longer available to perform work
What is the change in free energy of a system at chemical equilibrium? -slightly increasing -no net change -greatly increasing -slightly decreasing
-no net change
What is the change in free energy of a system at chemical equilibrium? -slightly increasing -slightly decreasing -no net change -greatly increasing
-no net change
Most cells cannot harness heat to perform work because: -heat is not a form of energy. -heat can never be used to do work. -cells do not have much heat; they are relatively cool. -temperature is usually uniform throughout a cell
-temperature is usually uniform throughout a cell
The hydrolysis of ATP: ATP + H2O → ADP + Pi is exergonic, with a ∆G of -7.3 kcal/mol under standard conditions. What is the source of the 7.3 kcal/mol released in this reaction? -both the energy released from breaking the terminal phosphate bond and the increase in entropy -breaking the terminal phosphate bond to form ATP -the difference between the potential energy in the bonds of ATP and the water molecule, minus the potential energy in the bonds of ADP and Pi. In other words: (potential energy in bonds of ATP + potential energy in bonds of H2O) - (potential energy in bonds of ADP + potential energy in bonds of Pi) = 7.3 kcal/mol -the increase in entropy from breaking apart ATP
-the difference between the potential energy in the bonds of ATP and the water molecule, minus the potential energy in the bonds of ADP and Pi. In other words: (potential energy in bonds of ATP + potential energy in bonds of H2O) - (potential energy in bonds of ADP + potential energy in bonds of Pi) = 7.3 kcal/mol
The respiration (catabolism) of glucose is exergonic.C6H12O6 + 6 O2 → 6 CO2 + 6 H2OWhat is the source of the free energy released in this reaction? -breaking the C-H covalent bonds -the difference between the potential energy in the bonds of the glucose and oxygen molecules, minus the potential energy in the bonds of the carbon dioxide and water molecules. In other words: (potential energy in bonds of 1 glucose molecule + potential energy in bonds of 6 O2 molecules) - (potential energy in bonds of 6 CO2 molecules + potential energy in bonds of 6 H2O molecules) = positive number -breaking both the C-H and O-O covalent bonds -breaking the O-O covalent bonds
-the difference between the potential energy in the bonds of the glucose and oxygen molecules, minus the potential energy in the bonds of the carbon dioxide and water molecules. In other words: (potential energy in bonds of 1 glucose molecule + potential energy in bonds of 6 O2 molecules) - (potential energy in bonds of 6 CO2 molecules + potential energy in bonds of 6 H2O molecules) = positive number
"Conservation of energy" is another way of stating: -the first law of thermodynamics -the second law of thermodynamics -the third law of thermodynamics -that the universe expends as little energy as possible in carrying out fundamental processes
-the first law of thermodynamics
The mathematical expression for the change in the free energy of a system is ∆G = ∆H - T∆S. Which of the following is (are) TRUE? -∆H is the change in enthalpy. -T is the temperature in degrees Celsius. -∆S is the change in free energy. -∆G is the change in entropy.
-∆H is the change in enthalpy.
The mathematical expression for the change in the free energy of a system is ∆G = ∆H - T∆S. Which of the following is (are) TRUE? -∆H is the change in free energy. -T is the temperature in degrees Celsius. -∆G is the change in enthalpy. -∆S is the change in entropy.
-∆S is the change in entropy.
The mathematical expression for the change in the free energy of a system is ∆G = ∆H - T∆S. Which of the following is (are) TRUE? ∆G is the change in free energy. ∆H is the change in entropy. ∆S is the change in enthalpy. T is the temperature in degrees Celsius.
∆G is the change in free energy.
