Bio Chapter 7

Front 1

Matter

Back 1

Anything that has mass and takes up space.

Front 2

Energy

Back 2

The capacity to do work, which is a change in the state or motion of matter

Front 3

Kilojoules (kJ)

Back 3

Energy is expressed in units of work

Front 4

Kinetic Energy

Back 4

When an archer draws a bow, kinetic energy, the energy of motion, is used and work is performed. When the string is finally released, the potential energy is converted to kinetic energy in the motion of the bow, which propels the arrow.

Front 5

Potential Energy

Back 5

The resulting tension in the bow and string represents stored, or potential, energy. This is the capacity to do work as a result of position or state.

Front 6

Chemical energy

Back 6

potential energy stored in chemical bonds

Front 7

Thermodynamics

Back 7

The study of energy and its transformation, governs all the activities of the universe, from the life and the death of organisms, to the life and the death of stars.

Front 8

Closed System

Back 8

Does not exchange energy with its surroundings

Front 9

Open System

Back 9

Does exchange energy with its surroundings

Front 10

First law of thermodynamics

Back 10

Energy cannot be created nor destroyed, although it can be transferred from one form to another, including conversions between matter and energy.

Front 11

Second law of thermodynamics

Back 11

When energy is converted from one form to another, some usable energy – that is energy available to do work – is converted into heat that disperses into the surroundings

Front 12

Entropy

Back 12

The measure of disorder or randomness in energy.
•
Organized, usable energy has a low entropy, whereas disorganized energy, such as heat, has a high entropy
o
Entropy is continuously increasing in the universe in all natural processes.

Front 13

Metabolism

Back 13

the sum of all chemical activities that take place within an organism.

Front 14

Anabolism

Back 14

Includes the various pathways in which complex molecules are synthesized from simpler substances, such as in the linking of amino acids to form proteins.

Front 15

Catabolism

Back 15

Includes the pathways in which larger molecules are broken down into smaller ones, such as in the degradation of starch to form monosaccharides

Front 16

Enthalpy

Back 16

The total bond energy (i.e. the energy required to break a specific bond) is essentially equivalent to the total potential energy of the system

Front 17

Free Energy

Back 17

the amount of energy available to do work under the conditions of a biochemical reaction

Front 18

•
H = enthalpy (total energy of the system)
•
G = free energy (usable energy)
•
T = absolute temperature of the system, expressed in Kelvin units
•
S = entropy (unusable energy)

Back 18

H = G +TS

Front 19

Exergonic reaction

Free energy decreases during an exergonic reaction

Back 19

releases energy and is said to be a spontaneous or “downhill” reaction, from higher to lower free energy.

Front 20

Endergonic reaction

Free energy increases during an endergonic reaction

Back 20

a reaction in which there is a gain of free energy.

Front 21

Diffusion is an exergonic reaction

Back 21

• Cells must expend energy to produce a concentration gradient. In this way, a concentration gradient is a form of potential energy. As particles move down the concentration gradient, it is degraded. Thus, free energy decreases and entropy increases.

Front 22

Dynamic equilibrium

Back 22

in which the rate of the reverse reaction equals the rate of the forward reaction

Front 23

Coupled reactions

Back 23

the thermodynamically favorable exergonic reaction provides the energy required to drive the thermodynamically unfavorable endergonic reaction.

Front 24

Adenosine Triphosphate (ATP)

Back 24

– In all living cells, energy is temporarily packaged within this chemical compound, which holds readily available energy for very short periods of time.

Front 25

Adenosine Diphosphate (ADP)

Back 25

when the terminal phosphate group is removed from ATP, this is the remaining molecule

Front 26

Phosphorylation reaction

Back 26

a reaction in which a phosphate group is transferred to some other compound

Front 27

Oxidation

Back 27

the chemical process in which a substance loses electrons

Front 28

Reduction

Back 28

the complementary process in which a substance gains electrons

Front 29

Redox reactions

Back 29

oxidation and reduction reactions are often called redox reactions because they occur simultaneously.

Front 30

Nicotinamide Adenine Dinucleotide (NAD+)

Back 30

one of the most frequently encountered acceptor molecules.

Front 31

Nicotinamide adenine dinucleotide phosphate (NADP+)

Back 31

is a hydrogen acceptor that is chemically similar to NAD+ but has an extra phosphate group.

Front 32

Flavin Adenine dinucleotide (FAD)

Back 32

a nucleotide that accepts hydrogen atoms and their electrons

Front 33

Cytochromes

Back 33

proteins that contain iron, the iron component accepts electrons from hydrogen atoms and the transfers these electrons to some other compound.

Front 34

Enzymes
• Most enzymes are proteins

Back 34

Help cells regulate the rates of chemical reactions, which are biological catalysts that increase the speed of a chemical reaction without being consumed by the reaction

Front 35

Catalase

Back 35

an enzyme that has the highest catalytic rate known

Front 36

Energy of activation (E subscript A)/activation energy

Back 36

all reactions, exergonic or endergonic have this energy barrier, which is the energy required to break the existing bonds and begin the reaction.

Front 37

Enzyme-Substrate Complex

Back 37

An enzyme helps control a chemical reaction by forming an unstable intermediate complex with the substrate, the substrate on which it acts.

Front 38

Active Sites

Back 38

Every enzyme contains one or more of these regions, to which the substrate binds, to form the enzyme-substrate complex.

Front 39

Induced Fit

Back 39

The binding of the substrate to the enzyme molecule causes this change, in the overall shape of the enzyme

Front 40

Oxidoreductases

Back 40

Catalyze oxidation-reduction reactions

Front 41

Transferases

Back 41

Catalyze the transfer of a functional group from a donor molecule to an acceptor molecule

Front 42

Hydrolases

Back 42

Catalyze hydrolysis reactions

Front 43

Isomerases

Back 43

Catalyze conversion of a molecule from one isomeric form to another

Front 44

Ligases

Back 44

Catalyze certain reactions in which 2 molecules join in a process coupled to the hydrolysis of ATP

Front 45

Lyases

Back 45

Catalyze certain reactions in which double bonds form or break

Front 46

Coenzyme

Back 46

An organic, nonpolypeptide compound that binds to the apoenzyme and serves as a cofactor

Front 47

Coenzyme A

Back 47

Is involved in the transfer of groups derived from organic acids.

Front 48

Metabolic Pathway

Back 48

Each enzyme carries out one step in a chain; such as changing molecule A into molecule B. Then molecule B is passed along to the next enzyme, which converts it into molecule C, and so on

Front 49

Feedback inhibition

Back 49

A type of enzyme regulation, in which the formation of a product inhibits an earlier reaction in the sequence

Front 50

Allosteric Site

Back 50

A receptor site that some enzymes have on some region of the enzyme molecule other than the active site

Front 51

Allosteric regulators

Back 51

Substances that affect enzyme activity by binding to allosteric sites

Front 52

Reversible inhibition

Back 52

Occurs when an inhibitor forms weak chemical bonds with the enzyme

Front 53

Competitive inhibition

Back 53

The inhibitor competes with the normal substrate for binding to the active site of the enzyme

Front 54

Noncompetitive inhibition

Back 54

the inhibitor binds with the enzyme at a site other than the active site.

Front 55

Irreversible inhibition

Back 55

An inhibitor permanently inactivates or destroys an enzyme when the inhibitor combines with one of the enzymes functional groups, either at the active site or elsewhere