AP BIOLOGY ENZYMES AND ENERGY
TEST QUESTIONS WITH COMPLETE
ANSWERS
Transport Work of Cells - ANSWER-Pumping of substances across membranes
against the direction of spontaneous movement
Mechanical Work of Cells - ANSWER--Beating of cilia
-contraction of muscle cells
-movement of chromosomes
Energy Coupling - ANSWER-Use of an exergonic process to drive an endergonic
one
-ATP is responsible for mediating most energy coupling cells
-Acts as the immediate source of energy that powers cellular work
ATP (Adenosine Triphosphate) - ANSWER-Contains a sugar ribose, nitrogenous
base adenine, 3 phosphate groups
ATP --> ADP - ANSWER--bonds between phosphate groups can be broken by
hydrolysis
-when a water molecule is added, terminal phosphate leaves ATP
-ATP molecule becomes ADP (Adenosine Diphosphate)
-->exergonic reaction
-->free-energy change
Phosphorylation - ANSWER--All 3 phosphate groups in ATP are negatively charged
-Like charges crowd together → mutual repulsion contributes to instability of the
region of the ATP molecule
-ATP donates/gives one phosphate to another molecule
-ATP is releasing energy
-another molecule (ADP) becomes ATP with donated phosphate
ATP Cycle - ANSWER-Energy released by catabolic reactions in the cell
phosphorylate ADP, regenerating ATP → nonspontaneous
-chemical potential energy stored in ATP drives most cellular work
-cellular respiration (catabolic) provides energy for the endergonic process of making
ATP
-plants use light energy to produce ATP
Enzyme - ANSWER--Macromolecule (type of protein) that acts as a catalyst,
chemical agent that speeds up a reaction without being consumed by the reaction
-Without enzymes, chemical traffic through metabolism pathways would be
congested and take a long time
Activation Energy - ANSWER-Amount of energy needed to push the reactants to the
top of an energy barrier (uphill) so that the "downhill" part of the reaction can begin
, How Energy is Supplied - ANSWER--Supplied by heat in the form of thermal energy
→ reactant molecules absorb from surroundings
-Absorption of thermal energy accelerates reactant molecules → they collide more
often and forcefully
-Makes the breakage of bonds more likely, agitating the atoms within the molecules
-When molecules have absorbed enough energy for the bonds to break, reactants
are in an unstable condition (transition state)
Lowering of Activation Energy - ANSWER-Enzymes speed up reaction by enabling
reactant molecules to absorb enough energy to reach the transition state at lower
temperatures
Substrate - ANSWER-Reactant an enzyme acts on
Enzyme-Substrate Complex - ANSWER-Enzyme binds to substrate
-converts substrate to the product(s) of the reaction
-example: enzyme sucrase catalyzes the hydrolysis of the disaccharide sucrose into
two monosaccharides (glucose and fructose)
Active Site - ANSWER-Region of an enzyme where catalysis occurs (typically a
groove or pocket on the enzyme's surface)
Enzymes Specificity - ANSWER-Complementary fit between the shape of its active
site and the shape of the substrate
Induced Fit - ANSWER-Brings chemical groups of the active site into positions that
enhance their ability to catalyze the chemical reaction
Characteristics of Enzymes - ANSWER--All enzymes are proteins that catalyze
reactions
-Work best at a specific pH and temperature
-Lower activation energy for reactions to occur
-Have an active site
-Require a substrate
Differences Between Enzymes - ANSWER--Shape (3D-form)
-Primary, Secondary, Tertiary, Quaternary Structures
-Size (number of amino acids it is built of)
-Activation energy needed to get them to work
-Temperature and pH optimum
-Hydrophobic or hydrophilic nature
Ribozymes - ANSWER--RNA molecule that functions as an enzyme
-Catalyzes own removal during RNA splicing
-Can be used only once --> enzymes repeatedly used
-Part of large ribosomal subunit RNA --> links amino acids during protein synthesis
-Used in: RNA splicing, viral replication, transfer RNA biosynthesis
TEST QUESTIONS WITH COMPLETE
ANSWERS
Transport Work of Cells - ANSWER-Pumping of substances across membranes
against the direction of spontaneous movement
Mechanical Work of Cells - ANSWER--Beating of cilia
-contraction of muscle cells
-movement of chromosomes
Energy Coupling - ANSWER-Use of an exergonic process to drive an endergonic
one
-ATP is responsible for mediating most energy coupling cells
-Acts as the immediate source of energy that powers cellular work
ATP (Adenosine Triphosphate) - ANSWER-Contains a sugar ribose, nitrogenous
base adenine, 3 phosphate groups
ATP --> ADP - ANSWER--bonds between phosphate groups can be broken by
hydrolysis
-when a water molecule is added, terminal phosphate leaves ATP
-ATP molecule becomes ADP (Adenosine Diphosphate)
-->exergonic reaction
-->free-energy change
Phosphorylation - ANSWER--All 3 phosphate groups in ATP are negatively charged
-Like charges crowd together → mutual repulsion contributes to instability of the
region of the ATP molecule
-ATP donates/gives one phosphate to another molecule
-ATP is releasing energy
-another molecule (ADP) becomes ATP with donated phosphate
ATP Cycle - ANSWER-Energy released by catabolic reactions in the cell
phosphorylate ADP, regenerating ATP → nonspontaneous
-chemical potential energy stored in ATP drives most cellular work
-cellular respiration (catabolic) provides energy for the endergonic process of making
ATP
-plants use light energy to produce ATP
Enzyme - ANSWER--Macromolecule (type of protein) that acts as a catalyst,
chemical agent that speeds up a reaction without being consumed by the reaction
-Without enzymes, chemical traffic through metabolism pathways would be
congested and take a long time
Activation Energy - ANSWER-Amount of energy needed to push the reactants to the
top of an energy barrier (uphill) so that the "downhill" part of the reaction can begin
, How Energy is Supplied - ANSWER--Supplied by heat in the form of thermal energy
→ reactant molecules absorb from surroundings
-Absorption of thermal energy accelerates reactant molecules → they collide more
often and forcefully
-Makes the breakage of bonds more likely, agitating the atoms within the molecules
-When molecules have absorbed enough energy for the bonds to break, reactants
are in an unstable condition (transition state)
Lowering of Activation Energy - ANSWER-Enzymes speed up reaction by enabling
reactant molecules to absorb enough energy to reach the transition state at lower
temperatures
Substrate - ANSWER-Reactant an enzyme acts on
Enzyme-Substrate Complex - ANSWER-Enzyme binds to substrate
-converts substrate to the product(s) of the reaction
-example: enzyme sucrase catalyzes the hydrolysis of the disaccharide sucrose into
two monosaccharides (glucose and fructose)
Active Site - ANSWER-Region of an enzyme where catalysis occurs (typically a
groove or pocket on the enzyme's surface)
Enzymes Specificity - ANSWER-Complementary fit between the shape of its active
site and the shape of the substrate
Induced Fit - ANSWER-Brings chemical groups of the active site into positions that
enhance their ability to catalyze the chemical reaction
Characteristics of Enzymes - ANSWER--All enzymes are proteins that catalyze
reactions
-Work best at a specific pH and temperature
-Lower activation energy for reactions to occur
-Have an active site
-Require a substrate
Differences Between Enzymes - ANSWER--Shape (3D-form)
-Primary, Secondary, Tertiary, Quaternary Structures
-Size (number of amino acids it is built of)
-Activation energy needed to get them to work
-Temperature and pH optimum
-Hydrophobic or hydrophilic nature
Ribozymes - ANSWER--RNA molecule that functions as an enzyme
-Catalyzes own removal during RNA splicing
-Can be used only once --> enzymes repeatedly used
-Part of large ribosomal subunit RNA --> links amino acids during protein synthesis
-Used in: RNA splicing, viral replication, transfer RNA biosynthesis
