Quiz 3

Which statement about enzymes is not true? Choose one: A. Enzymes reduce the activation energy required to initiate a spontaneous reaction. B. An enzyme can force an energetically unfavorable reaction to take place inside the cell. C. Enzymes can speed up energetically favorable reactions. D. Enzymes can help build large polymers.

B. An enzyme can force an energetically unfavorable reaction to take place inside the cell.

What is true of the breakdown of polymers inside living cells?Choose one: A. It is energetically unfavorable. B. It is associated with a negative change in free energy. C. It occurs without the need for enzymes.

B. It is associated with a negative change in free energy.

Which of the following statements regarding NADPH and NADH is true? Choose one: A. NADPH and NADH are used in separate biochemical pathways in cells. B. NADH carries electrons in animal cells and NADPH does the same in plants. C. NADPH and NADH deliver electrons to the same set of enzymes. D. NADPH loses a phosphate group to form NADH during biosynthetic reactions.

A. NADPH and NADH are used in separate biochemical pathways in cells.

Which statement about polymers is true? Choose one: A. Polymer synthesis requires an input of free energy and involves the release of water. B. Polymer synthesis requires an input of free energy and involves the consumption of water. C. Polymer breakdown requires an input of free energy and involves the release of water. D. Polymer breakdown requires an input of free energy and involves the consumption of water.

A. Polymer synthesis requires an input of free energy and involves the release of water.

Which statement is true about the removal of a terminal phosphate from ATP? Choose one: A. The reaction is energetically favorable. B. The reaction is associated with a positive change in ΔG°. C. The reaction is a condensation reaction.

A. The reaction is energetically favorable.

Which energy conversion characterizes photosynthesis? Choose one: A. electromagnetic (light) energy → chemical bond energy B. electromagnetic (light) energy → heat energy C. electromagnetic (light) energy → CO2 D. electromagnetic (light) energy → oxidation energy E. electromagnetic (light) energy → kinetic energy

A. electromagnetic (light) energy → chemical bond energy

Which of the following represents energy in its most disordered form?Choose one: A. heat energy B. kinetic energy of a moving object C. chemical bond energy D. electromagnetic (light) energy E. potential energy

A. heat energy

In a cell, the rate at which an enzyme will encounter its substrate depends on which of the following? Choose one: A. the concentration of the substrate B. the concentration of other proteins in the cytosol C. the size of the enzyme D. the way that the cytosol is structured

A. the concentration of the substrate

Which of the following does not occur in cells?Choose one: A. the use of heat to burn foodstuffs and transport glucose B. the use of chemical energy to transport organelles through the cytosol C. the metabolism of nutrients to produce useful energy stores D. the conversion of sunlight into energy stored in chemical bonds during photosynthesis

A. the use of heat to burn foodstuffs and transport glucose

All four possible reactions in the animation are energetically favorable; the energy of the four products is lower than the energy of the original starting molecule. Why does the starting molecule not completely and quickly convert to its possible products before the addition of heat or an enzyme? Choose one: A. The starting molecule can only form some of the products quickly. B. The starting substrate does quickly convert to the four products. C. An activation energy barrier exists that must be overcome for conversion to products. D. When heat was added to the reaction, only some of the products were produced.

C. An activation energy barrier exists that must be overcome for conversion to products.

Which of the following statements about NADPH and/or NADH is not true?Choose one: A. NADPH is an activated carrier molecule that is usually used in biosynthetic reactions to build energy-rich molecules. B. NADH is an activated carrier molecule that is usually used in oxidation reactions to produce ATP. C. NADPH is an activated carrier molecule that is used primarily by plants. D. All of these statements are incorrect regarding the activated carrier nature of these molecules.

C. NADPH is an activated carrier molecule that is used primarily by plants.

In thermodynamics, what does the term "free energy" refer to?Choose one: A. energy required to initiate a chemical reaction B. energy that cannot be harnessed to do work or drive chemical reactions C. energy that can be harnessed to do work or drive chemical reactions D. excess energy from a reaction that a cell does not use E. energy that cells borrow from the environment

C. energy that can be harnessed to do work or drive chemical reactions

Compared to adding heat to the system, what is the advantage of using an enzyme to overcome an energy barrier? Choose one: A. An enzyme speeds up a reaction more than heat does. B. An enzyme generates multiple different products using multiple pathways. C. An enzyme can catalyze a reaction in many different ways. D. An enzyme is specific for one desired pathway and end product

D. An enzyme is specific for one desired pathway and end product

Small molecules diffuse through the cytosol very efficiently by doing which of the following? Choose one: A. binding to larger molecules B. taking the shortest path from one location to another C. forming noncovalent bonds with other molecules D. moving randomly, knocked around by colliding with other molecules E. migrating along cytoskeletal microtubules

D. moving randomly, knocked around by colliding with other molecules

Which of the following does not describe an oxidation reaction?Choose one: A. the addition of oxygen atoms to a molecule B. the conversion of Fe2+ to Fe3+ C. the removal of electrons from a molecule D. the conversion of a chlorine atom to Cl-

D. the conversion of a chlorine atom to Cl-

What is the measure of disorder in a system called?Choose one: A. free energy B. enthalpy C. catabolism D. second law of thermodynamics E. entropy

E. entropy

For a biochemical reaction, ____________ energy is the term for the extra energy boost required to initiate an energetically favorable reaction within the cell.

activation

Reactions that use energy to drive the synthesis of molecules inside the cell are most specifically considered

anabolic