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Question: 1 a covalent bond between a hydrogen atom and an...

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1.   A covalent bond between a hydrogen atom and an oxygen atom represents what kind of energy?
a.   Kinetic energy
b.   Potential energy
c.   Mechanical energy
d.   Solar energy

2.   During a redox reaction the molecule that gains an electron is:
a.   Reduced and now has a higher energy level
b.   Oxidized and now has a lower energy level
c.   Reduced and now has a lower energy level
d.   Oxidized and now has a higher energy level

3.   When a hibernating animal uses its stored fat to power basic body functions (e.g., breathing), it is
a.   Converting kinetic energy to potential energy
b.   Converting kinetic energy to chemical energy
c.   Converting potential energy to kinetic energy
d.   Converting chemical energy go potential energy

4.   During certain stages of stages of cellular respiration, electrons are transferred from glucose molecules to a molecule called nicotinamide adenine dinucleotide (NAD+). In this example,
a.   Glucose is oxidized and NAD+ is reduced
b.   Glucose is reduced and NAD+ is oxidized
c.   Both glucose and NAD+ have gained protons
d.   Glucose has gained protons and NAD+ has lost protons.

5.   When a bear eats a salmon, some of the energy stored in the salmon is used by the bear for its activities and growth. Much of this energy originally in the salmon is dissipated as heat. This is an example of:
a.   The first law of thermodynamics
b.   The second law of thermodynamics
c.   100% efficient energy conversion
d.   A conversion of kinetic energy to potential energy

6.   An endergonic reaction has the following properties
a.   +G and the reaction is spontaneous
b.   +G and the reaction is not spontaneous
c.   -G and the reaction is spontaneous
d.   -G and the reaction is not spontaneous

7.   A spontaneous reaction is one which:
a.   The reactants have a higher free energy than the products
b.   The products have a higher free energy than the reactants
c.   An input of energy is required
d.   Entropy is decreased

8.   Where is energy stored in a molecule of ATP?
a.   Within the bonds between nitrogen and carbon
b.   In the carbon to carbon bonds round in the ribose
c.   In the phosphorous to oxygen double bond
d.   In the bonds connecting two terminal phosphate groups.

9.   An in active protein becomes activated by ATP. How does ATP activate the protein?
a.   A high energy phosphate form ATP attaches to the protein
b.   ATP is an enzyme
c.   ATP removes a phosphate from the protein
d.   An ATP molecules binds directly to the protein

10.   Cells use ATP to drive endergonic reactions because
a.   ATP is a universal catalyst
b.   Energy released by ATP hydrolysis makes G for coupled reactions more negative.
c.   Energy released by ATP hydrolysis makes G for coupled reactions more positive.
d.   The conversion of ATP to ADP is also endergonic.

11.   What is activation energy?
a.   The thermal energy associated with random movements of molecules
b.   The energy released through breaking chemical bonds
c.   The difference in free energy between reactants and products
d.   The energy required to initiate a chemical reaction

12.   Which of the following is not a property of an enzyme?
a.   An enzyme reduces the activation energy of a reaction
b.   An enzyme lowers the free energy of the reactants
c.   An enzyme does not change as a result of the reaction
d.   An enzyme works in both the forward and reverse directions of a reaction

13.   Which statement about the influence of temperature on enzymes is NOT true?
a.   All enzymes have the same intrinsic optimal temperature
b.   Raising the temperature may increase the activity of an enzyme
c.   Some enzymes are stable at the boiling point of water
d.   Raising the temperature may decrease the activity of an enzyme

14.   In competitive inhibition
a.   Two enzymes compete with each other for a substrate
b.   An inhibitor molecule binds to an allosteric site on an enzyme, causing a change in the active site.
c.   An inhibitor molecule binds to the active site of an enzyme, so that the substrate cannot bind
d.   The products of a reaction both compete for the active site.

15.   The enzyme aromatase is found in the cytoplasm of some cells and converts testosterone to estrogen. You decide to test aromatase from a particular cell type, and your lab partner admits that he drastically increased the pH in all the test tubes. Which of the following is a likely result?
a.   The enzyme will be denatured and the substrate will not bind to tis active site
b.   The enzyme will convert testosterone to estrogen at a faster rate.
c.   The mistake will have no effect, as enzymes are not sensitive to changes in ph.
d.   The G will be lowered and the reaction will proceed spontaneously.

16.   Consider the enzyme-catalyzed pathway below. It is regulated by feedback inhibition of enzyme 1. Which of the following statements is not accurate regarding this pathway?   

  A->B->C->D->E->F
a)   Compound F binds to the active site of enzyme 1
b)   Enzyme 1 contains an allosteric site for compound F
c)   When enough compound F is made in high enough levels, it shuts off its own synthesis
d)   When F binds to enzyme 1, it causes a conformational change

17.   Which of the following is a statement of the first law of thermodynamics?
a.   Energy cannot be created of destroyed.
b.   The entropy of the universe is decreasing.
c.   The entropy of the universe is constant.
d.   Kinetic energy is stored energy that results from the specific arrangement of matter
e.   Energy cannot be transferred or transformed

18.   Which of the following is an example of potential rather than kinetic energy?
a.   A boy mowing grass
b.   Water rushing over Niagara Falls
c.   A firefly using light flashes to attract a mate
d.   A food molecules made up of energy-rice macromolecules
e.   An insect foraging for food

19.   The mathematical expression for the change in free energy of a system is G=H -TS. Which of the following is (are) correct?
a.   S is the change in enthalpy, a measure of randomness
b.   H is the change in entropy, the energy available to do work
c.   G is the change in free energy
d.   T is the temperature in degrees Celsius

20.   What is the change in free energy of a system at chemical equilibrium?
a.   Slightly increasing
b.   Greatly increasing
c.   Slightly decreasing
d.   Greatly decreasing
e.   No net change

21.   A chemical reaction that has a positive G is correctly described as;
a.   Endergonic
b.   Endothermic
c.   Enthalpic
d.   Spontaneous
e.   Exothermic

22.   Which of the following best describe enthalpy (H)?
a.   The total kinetic energy of a system
b.   The heat content of a chemical system
c.   The system’s entropy
d.   The cell’s energy equilibrium
e.   The condition of a cell that is not able to react.

23.   Why is ATP an important molecule in metabolism?
a.   Its hydrolysis provides an input of free energy for exergonic reactions
b.   It provides energy coupling between exergonic and endergonic reactions
c.   Its terminal phosphate group contains a strong covalent bond that when hydrolyzed releases free energy.
d.   Its terminal phosphate bond has higher energy than the other two

24.   When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
a.   It is used to power yet more cellular work
b.   It is used to store energy as more ATP
c.   It is used to generate ADP from nucleotide precursors
d.   It is lost to the environment
e.   It is transported to specific organs such as the brain.

25.   When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (of any) to the cell?
a.   It is released as excreatory waste
b.   It can only be used to regertate more ATP
c.   It can be added to water and excreted as liquid
d.   It can be added to other molecules in order to activate them.

26.   How can one increase the rate of a chemical reaction
a.   Increase the activation energy needed
b.   Cool the reactants
c.   Decrease the concentration of the reactants
d.   Add a catalyst
e.   Increase the entropy of the reactants

27.   Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction;
a.   Entropy
b.   Activation energy
c.   Endothermic level
d.   Heat content
e.   Free-energy content

28.   The active site of an enzyme is the region that
a.   Binds allosteric regulators of the enzyme
b.   Is involve in the catalytic reaction of the enzyme
c.   Binds the products of the catalytic reaction
d.   Is in habited by the presence of a coenzyme or a cofactor

29.   Increasing the substrate concentration in a enzymatic reaction could overcome which of the following?
a.   Denaturation of the enzyme
b.   Allosteric inhibition
c.   Competitive inhibition
d.   Saturation of the enzyme activity

30.   If an enzyme solution is saturated with substrate, the most effective way to obtain a faster yield of product is to :
a.   Add more of the enzyme
b.   Heat the solution
c.   Add more substrate
d.   Add an allosteric inhibitor

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