Enzymes & Organic Chemistry

Question 1

acetyl CoA

Answer 1

the combination of an acetyl group derived from pyruvic acid and coenzyme A which is made from pantothenic acid (a B-group vitamin)

Question 2

activation energy

Answer 2

the amount of initial energy necessary for reactions to occur

Question 3

active site

Answer 3

a specific region on the enzyme where the substrate binds

Question 4

allosteric inhibition

Answer 4

the mechanism for inhibiting enzyme action in which a regulatory molecule binds to a second site (not the active site) and initiates a conformation change in the active site, preventing binding with the substrate

Question 5

anabolic

Answer 5

describes the pathway that requires a net energy input to synthesize complex molecules from simpler ones

Question 6

anaerobic cellular respiration

Answer 6

the use of an electron acceptor other than oxygen to complete metabolism using electron transport-based chemiosmosis

Question 7

ATP

Answer 7

• ATP is a small, relatively simple molecule, but within its bonds contains the potential for a quick burst of energy that can be harnessed to perform cellular work.

(adenosine triphosphate) the cell’s energy currency

Question 8

ATP synthase

Answer 8

a membrane-embedded protein complex that regenerates ATP from ADP with energy from protons diffusing through it

Question 9

bioenergetics

Answer 9

the concept of energy flow through living systems

Question 10

catabolic

Answer 10

describes the pathway in which complex molecules are broken down into simpler ones, yielding energy as an additional product of the reaction

Question 11

chemiosmosis

Answer 11

the movement of hydrogen ions down their electrochemical gradient across a membrane through ATP synthase to generate ATP

Question 12

citric acid cycle

Answer 12

a series of enzyme-catalyzed chemical reactions of central importance in all living cells that harvests the energy in carbon-carbon bonds of sugar molecules to generate ATP; the citric acid cycle is an aerobic metabolic pathway because it requires oxygen in later reactions to proceed

Question 13

citric acid cycle

Answer 13

a series of enzyme-catalyzed chemical reactions of central importance in all living cells that harvests the energy in carbon-carbon bonds of sugar molecules to generate ATP; the citric acid cycle is an aerobic metabolic pathway because it requires oxygen in later reactions to proceed

Question 14

competitive inhibition

Answer 14

a general mechanism of enzyme activity regulation in which a molecule other than the enzyme’s substrate is able to bind the active site and prevent the substrate itself from binding, thus inhibiting the overall rate of reaction for the enzyme

Question 15

electron transport chain

Answer 15

a series of four large, multi-protein complexes embedded in the inner mitochondrial membrane that accepts electrons from donor compounds and harvests energy from a series of chemical reactions to generate a hydrogen ion gradient across the membrane

Question 16

endergonic

Answer 16

describes a chemical reaction that results in products that store more chemical potential energy than the reactants

Question 17

enzyme

Answer 17

a molecule that catalyzes a biochemical reaction

Question 18

exergonic

Answer 18

describes a chemical reaction that results in products with less chemical potential energy than the reactants, plus the release of free energy

Question 19

feedback inhibition

Answer 19

a mechanism of enzyme activity regulation in which the product of a reaction or the final product of a series of sequential reactions inhibits an enzyme for an earlier step in the reaction series

Question 20

fermentation

Answer 20

the steps that follow the partial oxidation of glucose via glycolysis to regenerate NAD+; occurs in the absence of oxygen and uses an organic compound as the final electron acceptor

Question 21

glycolysis

Answer 21

the process of breaking glucose into two three-carbon molecules with the production of ATP and NADH

Question 22

heat energy

Answer 22

the energy transferred from one system to another that is not work

Question 23

kinetic energy

Answer 23

the type of energy associated with objects in motion

Question 24

metabolism

Answer 24

all the chemical reactions that take place inside cells, including those that use energy and those that release energy

Question 25

noncompetitive inhibition

Answer 25

a general mechanism of enzyme activity regulation in which a regulatory molecule binds to a site other than the active site and prevents the active site from binding the substrate; thus, the inhibitor molecule does not compete with the substrate for the active site; allosteric inhibition is a form of noncompetitive inhibition

Question 26

oxidative phosphorylation

Answer 26

the production of ATP by the transfer of electrons down the electron transport chain to create a proton gradient that is used by ATP synthase to add phosphate groups to ADP molecules

Question 27

potential energy

Answer 27

the type of energy that refers to the potential to do work

Question 28

substrate

Answer 28

a molecule on which the enzyme acts

Question 29

thermodynamics

Answer 29

• the science of the relationships between heat, energy, and work
• the study of energy and energy transfer involving physical matter.

Question 30

metabolic pathway

Answer 30

a series of chemical reactions that takes a starting molecule and modifies it, step-by-step, through a series of metabolic intermediates, eventually yielding a final product.

Question 31

anabolic

Answer 31

Build polymers

Question 32

catabolic

Answer 32

breaking down polymers into their monomers