Enzyms

Front 1

activation energy

Back 1

The amount of energy that reactants must absorb before a chemical reaction will start

Front 2

active site

Back 2

The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds

Front 3

active transport

Back 3

The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins.

Front 4

ATP

Back 4

(adenosine triphosphate)An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Front 5

calorie

Back 5

The amount of energy that raises the temperature of water by 1 degree Celsius.

Front 6

cellular respiration

Back 6

The aerobic harvesting of chemical energy from organic fuel molecules.

Front 7

chemical energy

Back 7

Energy stored in the chemical bonds of molecules; a form of potential energy.

Front 8

conservation of energy

Back 8

The principle that energy can neither be created nor destroyed

Front 9

diffusion

Back 9

The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area.

Front 10

endocytosis

Back 10

The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.

Front 11

energy

Back 11

The capacity to do work (to move matter against an opposing force).

Front 12

energy coupling

Back 12

In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.

Front 13

entropy

Back 13

A quantitative measure of disorder or randomness, symbolized by S.

Front 14

enzyme

Back 14

A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.

Front 15

exocytosis

Back 15

The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane.

Front 16

active site

Back 16

The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.

Front 17

allosteric regulation

Back 17

The binding of a molecule to a protein that affects the function of the protein at a different site.

Front 18

anabolic pathway

Back 18

A metabolic pathway that synthesizes a complex molecule from simpler compounds.

Front 19

ATP (adenosine triphosphate)

Back 19

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Front 20

bioenergetics

Back 20

The flow of energy through an animal, taking into account the energy stored in the food it consumes, the energy used for basic functions, activity, growth, reproduction, and regulation, and the energy lost to the environment as heat or in waste.

Front 21

catabolic pathway

Back 21

A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds.

Front 22

catalyst

Back 22

A chemical agent that changes the rate of a reaction without being consumed by the reaction.

Front 23

chemical energy

Back 23

Energy stored in the chemical bonds of molecules; a form of potential energy.

Front 24

coenzyme

Back 24

An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.

Front 25

cofactor

Back 25

Any non-protein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis.

Front 26

competitive inhibitor

Back 26

A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.

Front 27

cooperativity

Back 27

An interaction of the constituent subunits of a protein whereby a conformational change in one subunit is transmitted to all the others.

Front 28

endergonic reaction

Back 28

A non-spontaneous chemical reaction, in which free energy is absorbed from the surroundings.

Front 29

energy

Back 29

The capacity to do work (to move matter against an opposing force).

Front 30

energy coupling

Back 30

In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.

Front 31

entropy

Back 31

A quantitative measure of disorder or randomness, symbolized by S.

Front 32

enzyme

Back 32

A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.

Front 33

enzyme-substrate complex

Back 33

A temporary complex formed when an enzyme binds to its substrate molecule(s).

Front 34

exergonic reaction

Back 34

A spontaneous chemical reaction, in which there is a net release of free energy.

Front 35

exergonic reaction

Back 35

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Front 36

first law of thermodynamics

Back 36

The principle of conservation of energy. Energy can be transferred and transformed, but it cannot be created or destroyed.

Front 37

free energy

Back 37

The portion of a system’s energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system is calculated by the equation ΔG = ΔH - T Δs, where T is absolute temperature.

Front 38

free energy of activation

Back 38

The amount of energy that reactants must absorb before a chemical reaction will start; also called activation energy.

Front 39

heat

Back 39

The total amount of kinetic energy due to molecular motion in a body of matter. Heat is energy in its most random form.

Front 40

induced fit

Back 40

The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

Front 41

kinetic energy

Back 41

The energy of motion, which is directly related to the speed of that motion. Moving matter does work by imparting motion to other matter.

Front 42

metabolic pathway

Back 42

A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule into simpler compounds (catabolic pathway).

Front 43

metabolism

Back 43

The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways.

Front 44

non-competitive inhibitor

Back 44

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.

Front 45

phosphorylated

Back 45

Referring to a molecule that has been the recipient of a phosphate group.

Front 46

potential energy

Back 46

The energy stored by matter as a result of its location or spatial arrangement.

Front 47

substrate

Back 47

The reactant on which an enzyme works.

Front 48

thermodynamics

Back 48

(1) The study of energy transformations that occur in a collection of matter. See first law of thermodynamics and second law of thermodynamics. (2) A phenomenon in which external DNA is taken up by a cell and functions there.