Fi B/p 250-255

Front 1

Covalent bonds

Back 1

Strong molecular interactions mediated by shared electrons

Front 2

Non covalent bonds

Back 2

Weak reversible molecular interactions

Front 3

Types of non covalent bonds

Back 3

Ionic bonds

Hydrogen bonds

Vander waals bonds

Front 4

Ionic bonds

Back 4

Mediated by oppposite electrostatic charges

Front 5

Hydrogen bonds

Back 5

Mediated by a shared hydrogen atom

Front 6

Van der waals bonds

Back 6

A nonspecific attraction (occurs when any two atoms are 3-4 A• apart

Front 7

Water

Back 7

Polar

Triangular

Highly cohesive

Excellent solvent for polar molecules

Weakens ionic and H- bonds

Front 8

Water

Back 8

Polar

Triangular

Highly cohesive

Excellent solvent for polar molecules

Weakens ionic and H- bonds

Front 9

Carbonic anhydrase

Back 9

Catalyzes the reaction between CO2 and H2O

Extremely fast enzyme

Located largely in erythrocytes and kidneys

A metalloenzyme contains zinc

Front 10

Most CO2 is transported in the blood as

Back 10

Bicarbonate

Front 11

Laws of thermodynamics

Back 11

First law: the total energy of a closed system is conserved

Second law: the entropy of a closed system always increases

Front 12

Laws of thermodynamics

Back 12

First law: the total energy of a closed system is conserved

Second law: the entropy of a closed system always increases

Front 13

Enthalpy is the heat content of a system

Back 13

Entropy is the degree of disorder of a system

Front 14

Direct calorimetry

Back 14

Direct measurement of the amount of heat produced in a given system

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Direct calorimetry

Back 15

Direct measurement of the amount of heat produced in a given system

Front 16

Indirect calorimetry

Back 16

Measurement of the amount of heat produced in terms of inhaled O2 and exhaled CO2

Front 17

Enzymes

Back 17

Highly specific catalysts for biochemical reactions

Classified according to their mechanism of action

Front 18

Examples of metallic coenzymes of various enzymes

Copper- cytochrome oxidase

Iron- catalase

Peroxidase

Back 18

Magnesium- hexokinase , glucose-6- phosphatase

Pyruvate kinase

Nickel- urease

Zinc- carbonic anhydrase,

Alcohol dehydrogenase

Front 19

Enzymes composed of proteins combined with non protein structures (either organic or inorganic) that aid in their function

Back 19

Coenzymes

Cofactors

Prosthetic groups

Front 20

Coenzyme

Back 20

Non protein portion of an enzyme

Front 21

Apoenzyme

Back 21

Protein portion of an enzyme

Catalytically inactive by itself

Front 22

Halo enzyme

Back 22

Complete catalytically active enzyme

Apoenzyme + coenzyme

Front 23

Isoenzymes

Back 23

Enzymes with subtle molecular differences that catalyze the same reaction

Front 24

Classification of enzymes

OVER THE HILL

Back 24

Oxidoreductases

Transferases

Hydrolases

Isomerases

Lyases

Ligases

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Oxidoreductases

Back 25

Catalyze redox reactions

Front 26

Transferases

Back 26

Catalyze the transfer of functional groups

Front 27

Transferases

Back 27

Catalyze the transfer of functional groups

Front 28

Hydrolases

Back 28

Catalyze bond cleavage by hydrolysis

Front 29

Transferases

Back 29

Catalyze the transfer of functional groups

Front 30

Hydrolases

Back 30

Catalyze bond cleavage by hydrolysis

Front 31

Isomerases

Back 31

Catalyze a change in molecular structure

Front 32

Transferases

Back 32

Catalyze the transfer of functional groups

Front 33

Hydrolases

Back 33

Catalyze bond cleavage by hydrolysis

Front 34

Isomerases

Back 34

Catalyze a change in molecular structure

Front 35

Lyases

Back 35

Catalyze bond cleavage by elimination

Front 36

Ligases

Back 36

Catalyze the union of two molecules

Front 37

Metals and B complex vitamins

Back 37

Serve as the majority of nonprotein coenzymes

Front 38

Metals and B complex vitamins

Back 38

Serve as the majority of nonprotein coenzymes

Front 39

Induced fit model:

Substrate binding induces a conformational change in an enzyme

Back 39

The energy produced by these changes enables the reactions to progress

Hint 39

Front 40

Enzyme kinetics

Substrate concentration:

Increasing substrate concentration increases reaction rate only until the enzyme binding sites are saturated

Back 40

Maximum reaction velocity (Vmax) is achieved when any further increase in substrate concentration does not increase reaction rate

Front 41

Enzyme kinetics

Substrate concentration:

Increasing substrate concentration increases reaction rate only until the enzyme binding sites are saturated

Back 41

Maximum reaction velocity (Vmax) is achieved when any further increase in substrate concentration does not increase reaction rate

Front 42

The Michaelis constant (Km) is the

Back 42

Substrate concentration when the initial reaction velocity is half of the maximum reaction velocity

Illustrated mathematically by the Michaelis- Menten equation

Front 43

Km reflects the affinity of the enzyme for its substrate

Km is indirectly proportional to enzyme affinity

Back 43

Vmax is directly proportional to the substrate concentration

Front 44

Gibbs free energy change

Back 44

Determines reaction direction

If delta Gs > delta Gp, then delta G will be negative and the reaction will proceed spontaneously toward equilibrium

Equilibrium is attained when delta G=0

Front 45

Michaelis Menten equation

Back 45

Vi = Vmax . [S]/ Km + [S]

Front 46

Delta G provides no information about the reaction rate and is independent of the path of the reaction

Back 46

Reactions are based on their delta G

Exergonic

Endergonic

Front 47

Reaction direction

Back 47

Determined by the delta G

Front 48

Reaction equilibrium

A. A + B + Enz = C + D + Enz

B. Keq = [C][D][Enz]/ [A][B][Enz]

Back 48

A: any reaction with enzyme present

B: equilibrium constant of the reaction

Enzymes have no effect on reaction equilibrium

Front 49

Activation energy

Back 49

Is the energy needed to initiate a reaction

Front 50

Reaction rate :

Determined by the activation energy

Attaining activation energy requires an increase in reactant kinetic energy

Back 50

Kinetic energy is largely influenced by temperature and substrate concentration

Enzymes lower the activation energy of a reaction accelerating the rate

Front 51

What are the factors influencing reaction rate

Back 51

pH

Temperature

Enzyme concentration

Inhibitor concentration

Substrate concentration

Front 52

Classification of reactions based on delta G:

Reaction type: exergonic

Delta G: negative

Energy flow: released

Back 52

Reaction type: endergonic

Delta G : positive

Energy flow: required

Front 53

Change in factor for pH:

Extreme changes can alter the charged state of the enzyme or substrate

Back 53

Characteristics of pH:

Enzymes function within an optimal pH range

Front 54

Change in factor for pH:

Extreme changes can alter the charged state of the enzyme or substrate

Back 54

Characteristics of pH:

Enzymes function within an optimal pH range

Front 55

Change in factor for temperature:

An increase in temperature will increase the reaction rate

Back 55

Characteristics of temperature:

Extreme increase in temperature can cause enzyme denaturation

Front 56

Change in factor for pH:

Extreme changes can alter the charged state of the enzyme or substrate

Back 56

Characteristics of pH:

Enzymes function within an optimal pH range

Front 57

Change in factor for temperature:

An increase in temperature will increase the reaction rate

Back 57

Characteristics of temperature:

Extreme increase in temperature can cause enzyme denaturation

Front 58

Change in factor for enzyme concentration

Back 58

An increase in enzyme concentration will increase the reaction rate

Front 59

Change in factor for inhibitor concentration

Back 59

An increase in inhibitor concentration will decrease the reaction rate

Front 60

Change in factor for substrate concentration:

An increase in substrate concentration will increase reaction rate only until the enzyme binding sites are saturated

Back 60

Characteristics of substrate concentration:

Enzymes have a limited number of active sites