Chapter 10 Micro

Front 1

Autotrophs

Back 1

CO2 sole or carbon source

Front 2

Heterotrophs

Back 2

Reduced organic molecules from other organisms

Front 3

Phototrophs

Back 3

light

Front 4

Chemotrophs

Back 4

oxidation of organic or inorganic compounds

Front 5

Lithotrophs

Back 5

Reduced inorganic molecules

Front 6

Orgotrophs

Back 6

Organic molecules

Front 7

Photolithoautotrophy

Back 7

algae, purple and green sulfur bacteria, cyanobacteria

Front 8

Photoorganoheterotrophy

Back 8

purple and green nonsulfur bacteria

Front 9

Chemolithoautotrophy

Back 9

Sulfur-oxidizing bacteria

hydrogen, iron-oxidizing, and nitrifying bacteria

Front 10

Chemoorganoheterotrophy

Back 10

protozoa, fungi, and non photosynthetic abcteria (pathogens)

Front 11

Metabolism

Back 11

the total of all chemical reactions in the cell

Front 12

2 parts of metabolism

Back 12

catabolism and anabolism

Front 13

catabolism

Back 13

fueling reactions, energy-conserving reactions

provide ready source or reducing power (electrons)

generate precursors of biosynthesis

Front 14

anabolism

Back 14

the synthesis of complex organic molecules from simpler ones

requires energy from fueling reactions

Front 15

energy

Back 15

capacity to do work or to cause particular changes

Front 16

chemical work

Back 16

synthesis of complex molecules

Front 17

transport work

Back 17

take up nutrients, elimination of wastes, and maintenance of ion balnaces

Front 18

mechanical work

Back 18

movement of organisms or cells and movement of internal structures

Front 19

ATP

Back 19

used to transfer energy from cell's energy-conserving systems to the systems that carry out cellular work

Front 20

First law of thermodynamics

Back 20

energy cannot be created or destroyed; it can be changed from one form to another

Front 21

Second law of thermodynamics

Back 21

energy cannot be changed from one form into another without a loss of usuable energy

Front 22

Entropy

Back 22

measure of randomness or disorder

-organized/usable forms of energy -- low entropy

-unorganized/less stable forms -- high entropy

Front 23

Entropy of the universe is always _____ because _____

Back 23

increasing; energy conversions result in heat

Front 24

Free energy (G)

Back 24

the amount of energy that is free to do work after a chemical reaction

Front 25

negative delta G

Back 25

products have less free energy than reactants; reaction occurs spontaneously

Front 26

postive delta G

Back 26

products have more free energy than reactants, reaction occurs non-spontaneously

Front 27

Exergonic reactions

Back 27

energy is released

Front 28

Endergonic reactions

Back 28

require and input of energy

Front 29

Reversible reactions

Back 29

Have a free energy difference near zero, such a reaction is at equilibrium

Front 30

Equilibrium

Back 30

rate of forward reaction = rate of reverse reaction

Front 31

Equilibrium constant (Keq)

Back 31

expresses the equilibrium concentrations of products and reactants to one another

Front 32

Standard Reduction Potential E0

Back 32

-Equilibrium constant for an oxidation-reduction reaction

-a measure of the tendency of the reducing agent to lose electrons

Front 33

more negative E0

Back 33

better electron donor

Front 34

less negative E0

Back 34

better electron acceptor

Front 35

The greater the difference between the E0 of the donor and the E0 of the acceptor

Back 35

the more negative the free energy

Front 36

oxidation-reduction reactions

Back 36

electron transfers

Front 37

Purpose of electron carriers

Back 37

used to transfer electrons from an electron donor to an electron acceptor

Front 38

reducing agent/reductant

Back 38

electron donor

Front 39

oxidizing agent/oxidant

Back 39

electron acceptor

Front 40

NAD

Back 40

nicotinamide adenine dinucleotide

Front 41

NADP

Back 41

nicotinamide dinucleotide phosphate

Front 42

Electron Carrier examples

Back 42

NAD and NADP

FAD, FMN

coenzyme Q (CoQ)

Front 43

FAD

Back 43

flavin adenine dinucleotide

Front 44

FMN

Back 44

-flavin mononucleotide

-riboflavin phosphate

Front 45

Coenzyme Q (CoQ)

Back 45

a quinone, also called ubiqunone

Front 46

Biochemical pathways

Back 46

-creates complex networks

-dynamic pathways can be used to monitor changes in metabolite levels (flux)

Front 47

Protein catalysts

Back 47

have great specificity for the reaction catalyzed and the molecules acted on

Front 48

catalyst

Back 48

substance that increases the rate of a reaction without being permanently altered

Front 49

substrates

Back 49

reacting molecules

Front 50

products

Back 50

substrates formed by reaction

Front 51

Structure of enzymes

Back 51

composed of one or more polypeptides and sometimes nonprotein components

Front 52

apoenzyme

Back 52

protein component of an enzyme

Front 53

cofactor

Back 53

nonprotein component of an enzyme

Front 54

prosthetics group

Back 54

a firmly attached nonprotein component of an enzyme

Front 55

coenzyme

Back 55

a loosely attached nonprotein component of an enzyme

Front 56

holoenzyme

Back 56

apoenzyme + cofactor

Front 57

oxidoreductase

Back 57

oxidation-reduction reactions

Front 58

transferase

Back 58

reactions involving the transfer of groups between molecules

Front 59

hydrolase

Back 59

hydrolysis of molecules

Front 60

lyase

Back 60

removal of groups to form double bonds or addition of groups to double bonds

Front 61

isomerase

Back 61

reactions involving isomerizations (same # of atoms, different arrangement

Front 62

ligase

Back 62

joining of two molecules using ATP energy

Front 63

transition-state complex

Back 63

resembles both the substrates and the products

Front 64

activation energy Ea

Back 64

energy required to form transition-state complex

Front 65

enzymes ______ ___ reacts by _______ ___

Back 65

speeds up, lowering activation energy

Front 66

catalytic site

Back 66

site where enzyme and substrate bind

Front 67

How do enzymes lower activation energy?

Back 67

-by increasing concentrations of substrates at active site of enzyme

-by orienting substrates properly with respect to each other in order to form the transition-state complex

Front 68

Km

Back 68

substrate concentration required by the enzyme to operate at half its maximum velocity

Front 69

Vmax

Back 69

the rate of product formation when the enzyme is saturated with substrate and operating as fast as possible

Front 70

denaturation

Back 70

loss of enzyme's structure and activity when temperature and pH rises too much above optima

Front 71

competitive inhibitor

Back 71

directly competes with binding of substrate to active site

Front 72

noncompetitive inhibitor

Back 72

binds enzyme at site other than active site; changes enzyme's shape so that it becomes less active

Front 73

ribozymes

Back 73

RNA molecules that can catalyze reactions

Front 74

Thomas Cech & Sidney Altman

Back 74

discovered ribozymes - RNA molecules that can catalyze reactions

Front 75

Splicing of pre-rRNA

Back 75

Tetrahymena spp.

Front 76

Splicing of mitochondrial rRNA and mRNA

Back 76

Numerous fungi

Front 77

Splicing of chloroplast tRNA, rRNA, and mRNA

Back 77

plants an algae

Front 78

Splicing of viral mRNA

Back 78

viruses

Front 79

Regulation of metabolism

Back 79

-important for conservation of energy and materials

-maintenance of metabolic balance despite changes in environmetn

Front 80

3 major mechanisms of metabolism

Back 80

-metabolic channeling

-regulation of the synthesis of a particular enzyme (transcriptional and translational)

-direct stimulation or inhibition of the activity of a critical enzyme

Front 81

Metabolic channeling

Back 81

differential localization of enzymes and metabolites

Front 82

Compartmentation

Back 82

-differential distribution of enzymes are metabolites among separate cell structure or organelles

-can generate marked variations in metabolite concentratino

Front 83

Two important reversible control measures

Back 83

-allosteric regulation

-covalent modification

Front 84

Allosteric Regulation

Back 84

allosteric enzyme -enzyme inactive- cant bind to substrate

-effector binding alters shape of active site

Front 85

Covalent modification of enzymes

Back 85

reversible addition or removal of a chemical group alters enzyme activity

Front 86

Feedback inhibition (end product inhibition)

Back 86

inhibition of one or more critical enzymes in a pathway regulates entire pathway

Front 87

pacemaker enzyme

Back 87

catalyzes the slowest or rate-limiting reaction in the pathway

Front 88

isoenzymes

Back 88

different enzymes that catalyze the same reaction