Microbio Chapters 4-5

Front 1

what is the definition for metabolism?

Back 1

sum total of all chemical reactions in the body

Front 2

the metabolic process is divided into what two categories?

Back 2

- anabolic reactions

- catabolic reactions

Front 3

what is anabolism?

Back 3

there are reactions that require energy to take place

Front 4

what are examples of simple substances that combine to form complex molecules (anabolism)?

Back 4

amino acid ---> proteins

simple sugars ---> polysaccharides

Front 5

what is catabolism?

Back 5

- these are chemical reactions that break down complex organic compounds into simpler ones.

- these reactions release energy which can drive anabolic reactions

Front 6

what are examples of reactions that release energy which can drive anabolic reactions (catabolism)? reactions?

Back 6

glucose ---> pyruvic acid + ATP

pyruvic acid ---> TCA cycle---> ATP + CO2 + H2O

Fermentation ---> ATP + other byproducts

Front 7

what type of life processes do cells need constant energy for?

Back 7

- reproduction

- growth

- flagellar or ciliar movement

- movement of compounds or ions in and out of cells

Front 8

where do plants get their energy from?

Back 8

sun light

Front 9

where do most organisms get their energy from?

Back 9

chemical energy stored in chemical bonds

Front 10

In chemcial reactions, some reactions are ______ and others are _______.

Back 10

exergonic ; endergonic

Front 11

Exergonic is what type of reaction?

Back 11

energy releasing

Front 12

Endergonic is what type of reactions?

Back 12

energy absorbing

Front 13

what type of chemical reacion is ATP hydrolysis?

Back 13

exergonic reaction

Front 14

what can ATP hydrolysis by coupled with (as a reaction)?

Back 14

phosphorylation of glucose

Front 15

what type of chemical reaction is phosphorylation of glucose?

Back 15

endergonic reaction

Front 16

what different forms can energy exist in?

Back 16

- mechanical

- thermal (heat)

- electrical

- chemical

Front 17

what is the first law of thermodynamics?

Back 17

energy can be converted from one form to another, but cannot be created or destroyed

Front 18

what unit is used to measure energy?

Back 18

kilo calorie

Front 19

what is the definition of one kilo calorie?

Back 19

the amount of heat needed to raise the temperature of 1 kg of water by 1 degree C.

Front 20

do the products or reactions of a chemical formula have more energy?

Back 20

energy within the products is LESS than the energy of the reactants

Front 21

what is enthalpy?

Back 21

the difference in enrgy between the initial and final states of a reaction (so total energy released during a reaction)

Front 22

what is entropy?

Back 22

this is the unrecoverable free energy that is released after a reaction and it cannot be used to do work

- it's a measurement of the disorder of a system

Front 23

what is the second law of thermodynamics?

Back 23

all processes in the universe occur in such a way that there is an increase in total entropy

Front 24

the world constantly moves towards ________ disorder

Back 24

maximum

Front 25

what are spontaneous reactions?

Back 25

they are reactions that always proceed with an increase in entropy (as per second law of thermodynamics)

Front 26

do chemical reactions occur the same way as spontaneous reactions?

Back 26

yes, they also occur in way that there is an increase in entropy

Front 27

The reactions that move in the direction of the products have a ___________.

Back 27

negative DGo’, and cannot be reversed without an input in energy. The oxidation of glucose is an example:

C6H12O6 + 6O2 ® 6CO2 + 6H2O DGo’ = - 673 Kcal / mole

Front 28

what are autotrophs?

Back 28

- organisms tat use CO2 as their carbon source by coverting CO2 to organic compounds.

- nutrionally dependent on living things

Front 29

what are photoautotrophs?

Back 29

- have their energy source from sun light

Ex. algae salts, green plants, cyanobacteria, green and purple sulfer bacteria

Front 30

what are chemoautotrophs?

Back 30

- their energy sources come from inorganic compounds

- Ex: H, sulfur, Fe, nitrifying bacteria and methanogens recycle inorganic nutrients

Front 31

what are heterotrophs?

Back 31

- organisms whose energy and carbon sources are organic compounds

- Ex: proteins, carbs, lipids, nucleic acids

- they are dependent upon other life forms for survival

Front 32

what is food defined as?

Back 32

raw material from which nutrients are derived

Front 33

what are nutrients defined as?

Back 33

chemical substances required by a cell for metabolism, growth, and maintenance

Front 34

what are essential nutrients defined as?

Back 34

nutrients that are required by an organism

Front 35

what are examples of essential nutrients?

Back 35

- Carbon is needed to make proteins, carbohydrates, lipids, nucleic acids and CO2

- Nitrogen is needed to make proteins, DNA, RNA and ATP. Sources include: nitrogen gas (N2), NO3, and NO2

- Oxygen is needed for making organic compound production (autotrophs)

- Hydrogen is needed for organic and inorganic compounds. Sources include: H2S, CH4, H2

- Phosphorus is needed for nucleic acids, cellular energy transfer (ATP), phospholipids and coenzymes

- Sulfur is needed for protein structure (in S-S, aa) and enzyme function. Sources include: sulfate (SO4), sulfides (FeS), H2S, & S

Front 36

what is the most important molecule in any cell?

Back 36

water

Front 37

when it comes to nutrients, the role of hydrogen includes...?

Back 37

- maintain pH

- form H bonds in macromolecules

- act as a prime force in oxidation-reduction reactions of respiration

Front 38

what is the importance of certain inorganic compounds?

Back 38

- K ---> needed for protein synthesis and membrane function

- Na ---> needed for cell function and transport

- Ca ---> needed for cell wall stabilization and cell function endospores

- Mg ---> needed for chlorophyll, membrane and ribosome stabilization, and cell energetics

- Fe ---> needed for cytochrome pigments

Front 39

a rate of a reaction at a given temperature and concentration is determined by what?

Back 39

the activation energy, which is the amount of energy required to initiate a chemical reaction

Front 40

how can the rate of a chemical reaction be increased?

Back 40

- by increasing the rate of molecular collisions and the rate of movement of the reactants - this can be done by increase in temperature

- also by catalysts

Front 41

what are examples of increasing the reaction rate of a chemical reaction?

Back 41

- if a mixture of H2 + ½ O2 ® H2O is ignited with an electrical spark, it forms H2O immediately. The increase in temperature provides the Ea required

- if H2 + ½ O2 + Palladium catalyst lowers the Ea and the reaction can take place at room temperature

Front 42

what are propeties of enzymes?

Back 42

- enzymes are biological catalysts required for cellular reactions

- enzyme-substrate interactions are specific, catalyzing specific reactions

- are highly efficient

- needed in small quantities

- lower the activation energy

Front 43

how are enzyme-substrates formed?

Back 43

enzymes bind to active site and forms temporary enzyme-substrate complex

Front 44

how are enzymes highly efficient?

Back 44

they can speed up reactions up to 10,000,000,000 times

Front 45

why are enzymes needed in small quantaties?

Back 45

because one enzyme can catalyze up to 500,000 substrates per second

Front 46

what happens when enzymes lower the activation energy?

Back 46

they permit the reaction to proceed at a high rate at room temperature

Front 47

how many enzymes does each cell have?

Back 47

thousands

Front 48

what happens to reactions without enzymes?

Back 48

without enzymes, reactions can't occur fast enough to maintain life processes

Front 49

what kind of affect do enzymes have on molecular collisions?

Back 49

- they increase the frequency of molecular collisions

- also propery orient to colliding molecules

Front 50

what are the two type of enzymes?

Back 50

- endoenzymes

- exoenzymes

Front 51

what are endoenzymes like?

Back 51

- they are retained intracellularly

- function within the cell

Front 52

what are exoenzymes like?

Back 52

- they are secreted extracellularly

- they are used to break down large food molecules or harmful chemicals

Front 53

what are examples of endoenzymes?

Back 53

most enzymes used in metabolic pathways such as:

- hexokinase

- lactase

- lactate dehydrogenase

Front 54

what are examples of exoenzymes?

Back 54

- cellulase

- amylase

- penicillinase

Front 55

how does substrate work with enzymes?

Back 55

- comes in contact with the active site on enzyme and forms temporary enzyme-substrate complex

- after activated transition state reached, dissociates into reaction products and enzyme.

Front 56

what is amylase?

Back 56

- exoenzyme

- produced by bacteria like Bacillus to degrade starch

Front 57

what is gelatinase?

Back 57

- exoenzyme

- used by bacteria to break down gelatin

Front 58

what is a more accurate way of identifying bacteria than staining?

Back 58

- based on metabolic activities

Front 59

why are metabolic activities are better way of identifying bacteria rather than staining?

Back 59

- since they are a result of specific enzyme reactions, they are more reliable
- the reason is because enzymes depend on genetic code of bacteria

Front 60

what offers the best identification results in the lab?

Back 60

enzymes and their by-products

Front 61

why are certain indicators or chemical reagents added to certain carbohydrate or protein-containing media?

Back 61

to facilitate detection of the chemical reactions that take place when bacteria are inoculated on those certain carbohydrate or protein-containing media

Front 62

what is the principle for adding carbohydrate to the media?

Back 62

- glucose and lactose (simple sugars) used

- have inverted Durham tubes in them to test whether or not the organisms ferment one or both of of these carbs

- at same time, test if gas is produced

Front 63

what is a durham tube?

Back 63

- small tube that is inserted into the glocose or lactose fermentation tube

- used to trap any gas produced during fermentation

Front 64

how is gas prodcution determined on solid medium (like KIA tubes)?

Back 64

by seeing if presence of cracks in the media

Front 65

what are the two pH indicators?

Back 65

- phenol red (red at neutral pH)

- bromcresol purple (purple at neutral pH)

* both turn yellow in acidic pH

Front 66

what is iodine used for in the carb or protein containing media?

Back 66

used to detect whether or not starch is degraded

Front 67

Starch + Iodine always produces what color?

Back 67

blue-black color

Front 68

If there is no color change around bacterial colonies with starch + iodine, what does that mean?

Back 68

idicates production of amylase by the bacterium

Front 69

how is Kovac's reagent used in the carb/protein containing media?

Back 69

- this reagent contains para-dimethylaminobenzaldehyde

- used to detect degradation of tryptophan (amino acid)

Front 70

In the presence of the enzyme tryptophanase, what happens to tryptophan?

Back 70

- broken down into indole + pyruvic acid + ammonia

Front 71

What happens when Kovac's reagent is added to a medium containing tryptophan?

Back 71

- a red ring forms at the top of the tube

- This is a result of indole binding to Korva'c reagent and producing rosindole, which is a red=colored substance

Front 72

How is H2O2 used in carb/protein containing media?

Back 72

- this is hydrogen peroxide

- used to detect the production of enzyme called catalase in bacteria

Front 73

how is simmons citrate used in carb/protein containing media?

Back 73

- used to detect citrate degradation

- contains sodium citrate as the sole carbon source

- contains ammonium ions as nitrogen source

Front 74

if citrate is degraded, what will happen?

Back 74

- the CO2 produced will react with Na+ and H2O to produce alkaline compounds like Na2CO3

- this turns the bromthymol blue pH indicator to blue

Front 75

which pH indicator is used with simmons citrate?

Back 75

- bromthymol blue

- this indicator is color green at pH 6.9

Front 76

bacteria have specific ______ which degrade proteins

Back 76

enzymes

Front 77

which are more complex, proteins or carbs?

Back 77

proteins

Front 78

enzymes can be involved in the breakdown of proteins into what?

Back 78

usable amino acids

Front 79

what is the indole test?

Back 79

- one of the commonly used tests

- determines whether or not the byproducts (ammonia, pyruvic acid, indole) are due to the breakdown of tryptophan

Front 80

what is indole?

Back 80

one of the byproducts produced when the amino acid tryptophan is broken down into its component parts

Front 81

what is the only thing that can break tryptophan down into its byproducts?

Back 81

only bacteria that contain an enzyme called tryptophanase

Front 82

what are the 3 byproducts of tryptophan?

Back 82

- ammonia

- pyruvic acid

- indole

Front 83

what is the procedure of the indole test?

Back 83

- add few drops of Kovac's reagent to previously inoculated tryptone broth with test bacteria

Front 84

how is the indole test read?

Back 84

- development of red ring at top of tryptone broth indicates that bacteria has tryptophanase enzyme because if indole present, para-dimethylaminobenzaldehyde binds to indole and produces compound called rosindole, which has red color

- if no red color after addition of Kovac's reagent, indicates that organisms have no tryptophanase enzyme

Front 85

how does the cysteine desulfhydrase protein degradation test work?

Back 85

- if bacteri have cysteine desulfhydrse enzyme, why you inoculate them on medium that contains cysteine (or proteins containing the amino acid cysteine), the enzyme will break down cysteine

- the breakdown of cysteine makes other reactions possible

Front 86

what are other reactions that occur due to the breakdown of cysteine?

Back 86

- formation of hydrogen sulfide (H2S)
gas (smells like rotten eggs)

- if H2S formed as result of breakdown of cysteine in medium that also has Ferrous sulfate (FeSO4), will lead to formton of compound called ferrous sulfide (FeS)

- this results in formation of black precipitate on KIA, which contains both cysteine and ferrous sulfate

Front 87

how is carbohydrate metabolism in a KIA slant determined?

Back 87

- by observing chne to yellow, or red on the KIA slant and/or butt

Y/Y ---> glucose and lactose metabolized

R/Y ---> only glucose metabolized

R/R ---> neither glucose not lactose metabolized

Front 88

how is the presence of gelatinase enzyme tested?

Back 88

- by inoculating the culture tubes containing gelatin

- in lab, used Serratia marcescens and Escherichia coli

Front 89

how are the results of gelatin degradation read?

Back 89

- if after 24-48 incubation period the gelatin tube is coverted from a solid medium to a liquid medium, the organism has gelatinase enzyme

- if medium remains solid, the organism does not metabolize gelatin

Front 90

what is one of the easiest ways (besides morphology) to differentiate Staphylococci from Streptococci?

Back 90

using the catalase test

Front 91

what is the catalase enzyme?

Back 91

- belongs to a group of zymes knowns as cytochrome oxidase enzyme system

- the two enzymes of the group that are regularly used in the identification process of bacteria are catalase and oxidase

Front 92

what does aerobic mean?

Back 92

requires oxygen

Front 93

what does anaerobic mean?

Back 93

doesn't require oxygen

Front 94

what are bacteria that possess the cytochrome oxidase enzyme system able to do?

Back 94

oxidize reduced cytochromes with oxygen

Front 95

what does the reduction of oxygen result in?

Back 95

formation of a whole cascae of very toxic substances like

- O2-

- OCl-

- OH-

Front 96

when oxygen is reduced and toxins formed, how can organisms still survive?

Back 96

- have to have enzyme systems able to convert the toxic free radicals to non-toxic molecules

Front 97

which produces toxic substances - aerobes or anaerobes?

Back 97

- both produce the toxic substances when they are growing the the presence of oxygen

Front 98

what do aerobes convert in the catalase test?

Back 98

- the superoxide (O2-) to H2O2 which the superoxide dismutase (SOD enzyme)

Front 99

what do anaerobes convert in the catalase test?

Back 99

- covert H2O2 to H2O + O2 with the catalase enzyme

Front 100

why can't anaerobes survive in the presence of oxygen?

Back 100

they do not have the enzymes to convert the toxic radicals to non-toxic substances

Front 101

how do you read the results of the catalase test?

Back 101

- add two drops of H2O2 to Staph and Strep

- if observe air bubbles, bacteria are catalase positive

- if no bubbles produced, bacteria lacks catalase enzyme

Front 102

what are some rapid identification systems used to ID bacteria?

Back 102

- API system

- Enterotube II system

Front 103

why are rapid identification systems used?

Back 103

- to speed up the identification process

- to cut cost of the tests

Front 104

what system do we use in lab to ID unknowns?

Back 104

- only use the classical biochemical technique (NOT rapid system)

Front 105

what is the temperature range when using temperature to control bacterial growth?

Back 105

temperature ranges from freezing to incinerting

Front 106

what will destroy vegetative cells and spores completely?

Back 106

- Incinerating (like heating your inoculating loop on a Bunsen burner)

- Autoclaving

Front 107

what is another method that will destroy vegetative cells but not spores?

Back 107

boiling

Front 108

where are incinerating and/or autoclaving generally used to control microbial growth?

Back 108

- microbio labs

- medical establishments

- dental offices

Front 109

what methods are used in households to control microbial growth?

Back 109

- boiling

- refrigeration

*these methods are based on the principles of minimum and maximum bacterial temperature growth limits

Front 110

what are the temperature ranges in which microorganisms can grow?

Back 110

- minimum

- maximum

- optimum

Front 111

what is the optimum growth temperature?

Back 111

- temperature at which microorganisms will grow best and fastest

- because at this temperature, enzymes function best and at their highest efficiency

Front 112

what happens at temperatures that are more than the maximum growth temperature?

Back 112

- enzymes and other proteins will be denatured (irreversibly damaged)

- this will lead to death of the organism

Front 113

what happens at temperatures that are less than minimum growth temperature?

Back 113

- this temperature does not denature bacterial enzymes

- their efficiency will be decreased by inactivating them

- the slowing down of the metabolic rte to a great extent results in growth inhibition

Front 114

what is one peculiar bacterial activity that is affected by growth temperature?

Back 114

the expression of pigmentation

Front 115

what are the 3 major groups which indicates the wide range of temperature at which bacteria are able to grow?

Back 115

- Psychrophiles: which are those bacteria that will grow best between 0-20 celsius

- Mesophiles: which are bacteria that will grow best between 20-50 celsius

- Thermophiles: which are bacteria that will grow best above 50 celsius

Front 116

which bacteria produce spores?

Back 116

- Clostridia

- genus Bacillus

Front 117

what happens if matures spores are in vegetative cells during boiling?

Back 117

the begetative cells will die, but the spores will survive

Front 118

how is incineration used to destroy spores?

Back 118

use hot oven set at 180 celsius for 3 hours

Front 119

how is autoclaving used to destroy spores?

Back 119

combination of high pressure (15 p/i), steam, and high temperature (121 celsius) for a period of 15 mins.

Front 120

what is pH?

Back 120

- defined as the negative log of the hydronium ion concentration in a solution

- or simply as the hydrogen ion concentration ([H+]) in a solution

Front 121

what range of pH do majority of bacteria grow in?

Back 121

- very limited range

- 6.5 - 7.5

Front 122

what are neutrophiles?

Back 122

the majority of baceria that grow with a pH range of 6.5 - 7.5

Front 123

what is high pH known as?

Back 123

alkaline

Front 124

what is low pH known as?

Back 124

acidic

Front 125

what happens if neutrophiles are exposed to high or low pH?

Back 125

their enzymatic functions are hampered from functioning properly

Front 126

how are enzymes essential for bacteria?

Back 126

are essential for all metabolic activities of the bacteria

Front 127

how will alteration of enzymatic functions affect bacteria?

Back 127

it will affect the growth of the bacteria

Front 128

what are acidophiles?

Back 128

- bacteria that is able to grow at very low pH's (1-5)

- many bacteria and mold fall into this category

Front 129

what are alkalinophiles?

Back 129

- bacteria that are able to grow between pH's of 8.5-12.0

Front 130

why are many of the bacterial growth media converted to an acidic pH?

Back 130

as a result of the acidic byproducts during fermentation

Front 131

what can limit drastic pH shifts within the growth media?

Back 131

- buffers such as K2HPO4 or KH2PO4

Front 132

what is one of the most common methods used in the food industry to control bacterial growth?

Back 132

regulating the concentration of water in cells by controlling salt and sugar concentrations in the food storage solution

Front 133

what are some examples of the food industry controlling bacterial growth in their products?

Back 133

- use of salt in canned soups

- use of concentrated sugars in preserving fruits

Front 134

what is the principle of controlling bacterial growth by regulating the concentration of water in cells based on?

Back 134

osmotic pressure

Front 135

what is osmosis?

Back 135

movement of water across a cell membrane

Front 136

how does osmosis work in normal conditions?

Back 136

molecules move from a region of higher concentration to a region of lower concentration

Front 137

what are the three conditions that affects the movement of water across membranes?

Back 137

- hypotonic solution

- hypertonic solution

- isotonic solution

Front 138

what is hypotonic solution?

Back 138

- low osmotic pressure

- more solutes in the cells than outside

- water will move inside cells

- cells can burst

Front 139

what is plasmoptysis?

Back 139

- this is a condition that happens in hypotonic solution if cells can't pump out water and the cells lyse

Front 140

why are bacteria able to live and divide in hypotonic solution?

Back 140

partly because of the rigidity of their cell walls and prevent cell lysis

Front 141

gram positive or negative - which are more resistant to turgor pressure?

Back 141

gram positive due to their thick peptidoglycan layer

Front 142

what is hypertonic solution?

Back 142

- high osmotic pressure

- more solutes outside than inside of cell

- water molecules move from inside the cell to the outside

- cells shrivel

Front 143

what is plasmolysis?

Back 143

- a condition that happens in hypertonic solution because bacteria can't multiply because they lose too much of their cellular water

- this prevents bacteria from dividing and from conducting many cellular functions because there is not enough water to allow all the reactions to take place

Front 144

what is isotonic solution?

Back 144

- where water molecules are in same concentration inside as they are outside

- rate of water movement in andx out of cell will be the same and not affect the concentration in either direction

Front 145

what are halophiles?

Back 145

- "salt-loving"

- bacteria that are able to live in extremely high salt concentrations

- some are able to grow in salt concentrations of up to 30% and sometimes more

Front 146

what salt concentration do most cells live in?

Back 146

5% NaCl or less

Front 147

what kind of range of oxygen requirements do bacteria have in order to survive?

Back 147

they have a wide range of oxygen requirements

Front 148

what are the groups that bacteria are divided into based on their oxygen requirements/tolerance?

Back 148

- obligate aerobes

- obligate anaerobes

- facultative anaerobes

- microaerophiles

- aerotolerant

Front 149

what does the tolerance of bacteria to oxygen depend on?

Back 149

whether or not the bacteria have the necessary enzymes to detoxify oxygen radicals produced in the cells when they are exposed to oxygen

Front 150

what are obligate aerobes?

Back 150

- require oxygen to grow

- have the required enzymes (including superoxidase dismutase and catalase enzymes) which are involved in converting O2- and H2O2 and O2 when they grow in presence of oxygen

-

Front 151

what are examples of obligate aerobes?

Back 151

- mycobacteria spp.

- micrococcus spp.

- pseudomonas spp.

Front 152

what are obligate anaerobes?

Back 152

- bacteria that can't survive in presence of oxygen

- if come in contact with oxygen, substances like O2- and H2O2 and other radicals will be formed (these will kill bacteria because they don't have the required enzymes that would convert the toxic molecules to non-toxic substances

Front 153

what are examples of obligate anaerobes?

Back 153

Some are very serious pathogens:

- Colostridium tetani (causes tetanus)

- C. Botulinum (causes botulism)

- C. perfringens (causes gas gangrene)

Front 154

what are facultative anaerobes?

Back 154

- grow both in presence and absence of oxygen

- are able to conduct fermentation when growing in absence of oxygen

- respiration when they are growing in presence of oxygen

Front 155

what are examples of facultative anaerobes?

Back 155

- Escherichia coli

- Staphylococcus aureus

- proteus vulgaris

Front 156

what are microaerophiles?

Back 156

- can't grow at atmospheric oxygen concentrations

- require oxygen concentration of about 5%

Front 157

What are examples of microaerophiles?

Back 157

- Camplobacter spp. (bacteria thats involved in causing gastrointestinal problems)

- Treponema pallidum (causes syphilis)

- Actinomyces israelii (causes lumpy jaw)

Front 158

what are aerotolerant bacteria?

Back 158

- can conduct fermentation both under aerobic and anaerobic conditions

Front 159

what are examples of aerotolerant bacteria?

Back 159

- Streptococcus lactis

- Lactobacillus spp.

Front 160

what medium is used in lab to determine the oxygen requirements for bacteria?

Back 160

- thioglycollate medium

Front 161

why is thioglycollate used in lab?

Back 161

because this medium contains sodium thyoglycollate, a reducing agent that will bind with free oxygen and create an anaerobic environment at the bottom of the test tube.

Front 162

what is the resarzurin indicator?

Back 162

this is added to the thioglycollate medium as an indicator to measure oxidation reduction reactions

Front 163

what are the results of the resarzurin indicator?

Back 163

- is colorless in anaerobic conditions

- is pink in aerobic conditions

Front 164

what is a cofactor on enzymes?

Back 164

- some enzymes have cofactors

- its a compound tightly bound to an enzyme surface

- required for enzymatic activity

- they're non-proteins which may be organic (vitamin derivatives known as coenzymes) or inorganic (metallic ions like Mg++, Na+)

Front 165

what are cofactors involved in?

Back 165

- carboxylation

- electron transport

- transamination

- transfer of carbon units

- group transfers

Front 166

enzyme composition may be composed of....?

Back 166

- Protein part, know as ---> apoenzyme

- Non-protein part, known as
---> cofactor

- Apoenzyme + cofactor ---> holoenzyme

Front 167

how do enzymes facilitate cellular chemical reactions?

Back 167

- by donating or accepting electrons

- donating or accepting atoms

Front 168

during what temperature do enzymes move at a slower rate?

Back 168

during low temperatures

Front 169

how can changes in pH affect enzymes?

Back 169

- pH can affect the charge characteristics of amino acids, comprising the structure of the enzyme and its active sites

Front 170

what two things must be set correctly in a growth medium in order for an enzyme to work optimally?

Back 170

temperature and pH

Front 171

what are enzyme inhibitors?

Back 171

- they prevent or slow down enzymatic actions either in a competitive or non-competitive manner

Front 172

what are the two types of enzyme inhibitors?

Back 172

- competitive inhibitors

- non-competitive inhibitors

Front 173

what do competitive inhibitors do?

Back 173

they bind to the active site of enzymes and inactivate its activity

Front 174

what do non-competitive inhibitors do?

Back 174

they bind to enzymes at sites other than the substrate binding site and inactivate enzymes

ex. cyanide, mercury, arsenic

Front 175

what are the two types of binding sites that allosteric enzymes have?

Back 175

- an active site, where substrate binds

- an alosteric site, where effectors bind

Front 176

what do molecules that bind to the allosteric site do?

Back 176

they change the enzyme conformation at the active site, inhibiting enzyme activity

ex, feedback inhibition

Front 177

what is respiration?

Back 177

is the oxidation of glucose to CO2 + H2O + energy

- can occur aerobically or anaerobically

Front 178

where does aerobic respiration occur?

Back 178

- occurs in the cytoplasm and mitochondria (in bacteria, occurs in the membrane)

Front 179

what kind of net does aerobic respiration generate?

Back 179

a net of 36 (38 total) ATP molecules

Front 180

where does anaerobic respiration occur?

Back 180

- aka fermentation

- common in bacteria and protista

- takes place in the cytoplasm

Front 181

what kind of net does anaerobic respiration generate?

Back 181

net of 2 ATP molecules

Front 182

what are the 3 steps of aerobic respiration?

Back 182

1) Glycolysis

2) Kreb's cycle

3) Electron transport system

Front 183

what are the steps of glycolysis?

Back 183

- glucose is oxidized ---> pyruvate

- occurs in cytoplasm

- generates 2 ATP (net) and 2NADH molecules

Front 184

what are the steps of the Kreb's cycle?

Back 184

- occurs in the mitochondria (and in membrane in bacteria)

- pyruvate oxidized to ---> CO2 + H2O

- generates 2 ATP, * NADH, 2 FADH and molecules

Front 185

what are the steps of the electron transport system?

Back 185

- occurs in the mitochondria (in the membrane in bacteria)

- generates 32 ATP molecules

- oxygen acts as the final electron acceptor

Front 186

how can ATP be generated?

Back 186

ADP + P ---> ATP

- Substrate level phosphorylation

- chemiosmotic-phosphorylation

- generation of ATP using energy from protons passing across a membrane through ATP synthase

Front 187

what is fermentation?

Back 187

its the incomplete oxidation of glucose or other CHO in the absence of O2

Front 188

what does alcoholic fermentation in yeast result in?

Back 188

- pyruvic acid ---> ethanol +CO2

Front 189

what does acidic fermentation result in?

Back 189

-streptococcus and lactobacillus

- pryruvic acid ---> lactic acid (cheese, yogurt)

Front 190

what does mixed acid fermentation result in?

Back 190

- produce combination of acids:

pyruvic acid ---> acetic, lactic, succinic, and formic acids, etc

Front 191

what do propionbacterium produce?

Back 191

produce mostly propionic acid, which gives flavor to Swiss cheese

Front 192

what type of environments can microorganisms live in?

Back 192

- hot

- cold,

- saline

- alkaline

- acidic

- neutral

- oxygen free

- in air and toxic

Front 193

what does the growth and survival of microorganisms depend on?

Back 193

- Availability of nutrients and energy sources

- ambient temperature of the locality

- absence of presence of certain gases

- osmotic pressure of solutions

- pH

- presence or absence of light or radiation

- presence or absence of other organims in the environment

Front 194

what do microorganisms need nutrients for?

Back 194

- growth

- cellular functions

- metabolic functions

Front 195

where do microorganisms get their nutrients from?

Back 195

- ranges from simple substances like sulfur by some bacteria to protozoa that digest cellulose

Front 196

what elements do organims require?

Back 196

- carbon

- hydrogen

- nitrogen

- potassium

- oxygen

- phosphorous

- calcium

- iron

- chlorine

- sulfur

Front 197

what two categories can nutrients be divided into?

Back 197

- macronutrients

- micronutrients

Front 198

what are macronutrients?

Back 198

-these are nutrients needed for general cellular metabolism

- generally required in large quantities

Front 199

what are examples of macronutrients?

Back 199

- carbs

- lipids

- proteins

(organic nutrients)

Front 200

what are micronutrients?

Back 200

- these are essential nutrients that are only required in trace amounts for enzymatic funtions

Front 201

wha are examples of micronutrients?

Back 201

- manganese

- zinc

- nickel

(inorganic nutrients)

Front 202

what are the two categories that microorganisms are divided into based on what their energy source is?

Back 202

- autotrophs

- heterotrophs

Front 203

what are the subcategories of autotrophs?

Back 203

- photoautotrophs

- chemoautotrophs

Front 204

what are photoautotrophs?

Back 204

- organisms that are capable of derviving energy from sun

- in process of photosynthesis

Front 205

what are chemoautotrophs?

Back 205

- organisms that derive energy from chemical reactions

- use simple inorganic molecules such as hydrogen gas, hydrogen sulfide, or sulfer

Front 206

what are heterotrophs?

Back 206

organisms that obtain energy and carbon source from organic compounds

- do this by respiration or fermentation

- include all animals, most protozoa, fungi , and bacteria

Front 207

what are the groups that bacteria is divided into based on their growth temperature?

Back 207

- psyhrophiles (-20 ---> 20 C)

- mesophiles (20 ---> 50 C)

- thermophiles (50 ---> 110 C)

Front 208

what are examples of psychrophiles?

Back 208

- Staphycocci

- Listeria monocytogenes

Front 209

what temperature do most human pathogens grow between?

Back 209

- 20 ---> 50 C

- optimum temperature around 37 C (which is human body temp)

(mesophiles)

Front 210

why can thermophiles grow in higher temperatures?

Back 210

they have heat stable proteins

Front 211

which enzymes have enabled the polymerase chain reaction (PCR)?

Back 211

enzymes obtained from thermophiles

Front 212

what are neutrophiles?

Back 212

- have pH of 7

- majority of bacteria grow around this pH

Front 213

what phases does the bacterial growth curve have?

Back 213

- lag

- log

- stationary

- death

Front 214

what happens in the lag phase of the bacterial growth cycle?

Back 214

- bacteria adapt to the growth environment

- increase in size

- adjust their metabolism

- repair cell components

Front 215

what happens in the log phase of the bacterial growth cycle?

Back 215

- cells frow at a logarithmic rate

- have increased metabolic activity

Front 216

what happens in the stationary phase of the bacterial growth cycle?

Back 216

- average cell population remains constant

- nutrients are depleted

- production of toxic materials that decrease cell growth increase

Front 217

what happens in the death phase of the bacterial growth cycle?

Back 217

- death of cells occurs due to physical stress, lack of ribosomal repair and protein depletion

Front 218

what are examples of some methods used to control growth of microorganisms in ancient times?

Back 218

- salting

- smoking

- drying of food materials

Front 219

what did the Egyptians do to control bacterial growth?

Back 219

-had sophisticated embalming methods

- introduced filtration of wine and water

Front 220

what did the Greeks and Romans do to control bacterial growth?

Back 220

- burned clothes and corpses during epidemics

- this is similar to what they did during the Great Plague, along with burying people in mass graves

Front 221

what are some physical methods used to kill or limit microbial growth?

Back 221

- heat

- radiation

- antibiotics

- masks, gloves, gowns, and hand washing

- fliteration

- pasturization

Front 222

whats the most effective and widely used method for killing or limiting microbials?

Back 222

- heat (dry or moist)

Front 223

what are two ways that radiation can be when killing microbials?

Back 223

can be:

- microbicidal

- microbistatic

Front 224

how does the filtration method work to control microbials?

Back 224

- used to remove mircrobes from liquids and air based on their pore size

Front 225

how does the pasturization method work to control microbials?

Back 225

- foods and drinks (like milk, juices, beer, wine) are pasturized to reduce microbial load

- done by heating to 71.6 C for 15 seconds or 63-66 C for 30 mins.

Front 226

how much bacteria does pasturized milk have?

Back 226

about 2000 bacteria per drop of milk

Front 227

what are new techniques now used to sterlize milk?

Back 227

- by heating it at 134 C for 1-2 seconds, this will keep it godo for up to 3 months

Front 228

does moist or dry heat require more time for sterlization?

Back 228

dry heat

Front 229

how many times are bacterial spores more resistant than vegetative cells?

Back 229

10 times more

Front 230

at what temperature and time does it take to kill non-enveloped and enveloped viruses?

Back 230

- non-enveloped: 57 C, 29 min

- enveloped: 54 C, 22 min

Front 231

at what temperature and time does it take to kill fungal spores and yeasts?

Back 231

- fungal spores: 76 C, 22 min

- Yeasts: 59 C, 19 mins

Front 232

what what temperature and time does it take to kill other bacteria?

Back 232

- non-spore forming pathogenic bacteria: 58 C, 28 min

- non-spore forming non-pathogenic bacteria: 61 C, 18 min

- Vegetative stage of spore-forming bacteria: 58 C, 19 min

Front 233

what does non-ionizing radiation do?

Back 233

- excites atoms by raising them to a higher energy state, but does not ionize

- causes abnormal base pairings (T-T), (T-C)

Front 234

what is UV (non-ionizing) effective between?

Back 234

- 240-280 nM

- most effective at 260 nM

Front 235

What does UV not penetrate?

Back 235

* its not as penetrating as ionizing radiation

Doesn't penetrate:

- solids

- glass

- paper

- plastics

Front 236

UV causes generation of ______.

Back 236

free radicals

Front 237

what does ionizing radiation do?

Back 237

- causes severe DNA mutations

- is effective in sterilizing heat and chemical sensitive materials

- can sterilize through packages and wrappings

- used to sterilize medical products (vaccines, druges, instruments, syringes, sutures, and surgical gloves)

Front 238

what are examples of ionizing radiations?

Back 238

- y-rays (more penetrating)

- X-rays (intermediate penetrating)

- B-particles (least penetrating)

Front 239

when choosing an anti-microbial agent, what factors does one have to consider?

Back 239

- solubility

- stability

- spectrum of action

- modes of action (protein, DNA, cell wall)

- resistance to inactivation

- corrosive properties

- toxicity

- price

Front 240

we now have anti-bacterial agents that will...?

Back 240

- kill

- sanitize

- deodorize

- fight plaque

- sterilize

- clean the air

Front 241

what anti-microbial chemicals have been in use since the 1800s?

Back 241

- chloride of lime

- iodine

Front 242

how are the antimicrobial activity in agents classified as?

Back 242

- high

- intermediate

- low

Front 243

what can antimicrobial agents with HIGH classification do?

Back 243

- sterilize and kill vegetative cells and spores

- used to sterilize thigns like heart and lung equipment, catheters, and implants

Front 244

what can antimicrobial agents with INTERMEDIATE classification do?

Back 244

- capable of killing fungal spores and pathogens

- used to disinfect materials including equipment like endoscopes

- can NOT kill bacterial spores

Front 245

what can antimicrobial agents with LOW classification do?

Back 245

- can kill only vegetative cells like bacteria, fungi, and some viruses

Front 246

______ are highly effective microbicidals and sporicidals if used _______.

Back 246

halogens ; for long periods of time

(fluorine, chlorine, bromine, iodine)

Front 247

which halogens are dangerous?

Back 247

- Fluorine and bromine, so they are not used that much.

Front 248

which level of activity does chlorine have?

Back 248

intermediate

Front 249

how much chlorine is needed to make water safe to drink?

Back 249

0.6 - 1.0 parts per million of chlorine

Front 250

in which form does chlorine work best?

Back 250

both gaseous and liquid forms

Front 251

how does chlorine work?

Back 251

forms hypochlorites (OCl), and chloramines (NH2Cl), which, when dissolved, form hypochlorous acid (HOCl)

- this acid oxidizes the sulfhydryl (S-H) on systeine and denatures enzymes by interfereing with S-S bridges on enzymes

Front 252

when is chlorine not effective?

Back 252

- if used in alkaline pH

- in excess organic matter

- inactivated by sun light

Front 253

what are chloramites?

Back 253

- they are considered to be safer than pure chlorine

- being used more and more because believed that chlorination can cause cancer

Front 254

what is household bleach?

Back 254

- about 5% of sodium hypochlorite

Front 255

what level of activity does iodine have?

Back 255

intermediate level

Front 256

what are the two primary forms of iodine?

Back 256

- free iodine (I2)

- iodophores

Front 257

how does iodine affect cells?

Back 257

- penetrates them and interferes with normal cell functions

- does this by binding to H and S-S bonds of enzymes in similar way as chlorine

Front 258

what is iodine not affected by?

Back 258

not affected by organic matter

Front 259

how much iodide does Aqueous Iodine contain and where is it used?

Back 259

- contains 2% and 2.4% sodium iodide

- used in surgery and topical disinfections

Front 260

what are higher concentrations of iodine used for?

Back 260

- higher concentrations are 5% iodine and 10% potassium iodine

- used for disinfecting rubber instruments and thermometers

Front 261

what is tincture iodine?

Back 261

- 2% iodine dissolved in 70% alcohol

Front 262

are higher concentrations of iodine dangerous?

Back 262

- Yes, they are toxic to tissue

- should not be used topically

Front 263

what are phenols?

Back 263

- carbolic acid

- these are poisonous compounds that are derived from coal tar

- they are effective microbicidal agents

Front 264

who introduced phenols?

Back 264

- Joseph Lister (1867)

Front 265

how do phenols affect the cell?

Back 265

- disrupt cell walls and cell membranes

- precipitate proteins and inactivate enzymes

- therefore, are strong cell poisons (so not commonly used)

Front 266

what are alcohols?

Back 266

- hydrocarbons which have one or more - OH groups

- they are used to disinfect

Front 267

which alcohols are used for microbial control?

Back 267

- ethyl

- isopropyl alcohol

Front 268

what do alcohols in concentrations of 50-95% do?

Back 268

they are able to dissolve membrane lipids

Front 269

what does 100% alcohol do?

Back 269

dehydrates cells

Front 270

what what materials is alcohol used as a disinfectant?

Back 270

- masks

- electrodes

- thermometers

* by soaking them for 15-20 mins

Front 271

what will inhalation of alcohol vapors do?

Back 271

adversely affect the nervous system

Front 272

what is hydrogen peroxide H2O2?

Back 272

- germicidal colorless liquid

- it is is bactericidal, viricidal, fungicidal and at higher concentrations it is also sporocidal

Front 273

when can hydrogen peroxide decompose?

Back 273

- in presence of light, metals, and catalase

Front 274

The toxic products of oxygen in cells are _______, which are __________.

Back 274

hydroxyl free radicals (-OH); highly toxic

Front 275

what does the catalase enzyme do to hydrogen peroxide?

Back 275

- neutralizes it

- some bacteria have this enzyme to do that

- amount used during disinfection is too much for the bacteria to neutralize

Front 276

what is 1-2% silver nitrate used for?

Back 276

- preventing gonococcal infections in newborns

- in some countries, has been replaced by antibiotics because of resistance problems

- used on mouth ulcers

- used during root canals

- for dressings for burn patients

Front 277

what is ethylene oxide?

Back 277

- effective gas used to sterilize materials (explosive gas)

- strong alkalating agent

- vigorously reacts with DNA and functional groups of proteins

- blocks DNA replication and enzymatic action

- has microbicidal and sporocidal effects

- is slow acting (90-180 min) but very effective sterilizer

Front 278

what needs to be done with ethylene oxide to use it safely?

Back 278

- since explosive gas, needs to be mixed with CO2 for sterilization purposes

Front 279

what is ethylene oxide used to disinfect?

Back 279

- heart pacemakers

- artificial heart valves

- surgical supplies

- syringes

- petri dishes

- dry foods

- druges

- nuts

- starches

- spices

Front 280

what is one of the most important discoveries in medicine?

Back 280

discovery of antibiotics

Front 281

what two categories are antibiotics divided into?

Back 281

Based on their spectrum of activity:

- Narrow spectrum antibiotics

- Broad spectrum antibiotics

Front 282

what do narrow spectrum antibiotics kill?

Back 282

kill one or a few bacterial types ( G+ or G - )

Front 283

what do broad spectrum antibiotics kill?

Back 283

kill wide range of bacteria (G+ and G-)

Front 284

what are some antibiotics?

Back 284

- Penicillin G

- Methicillin

- Ampicillin B

- Amoxicillin

- Tetracycline

- Chloramphenicol

- Erythromycin

- Vancomycin

- Clindamycin

Front 285

what is penicillin G?

Back 285

- narrow spectrum antibiotic

- used as drug of choice when bacteria are sensitive because of its low cost and low toxicity

- can easily be hydrolyzed by penicillinase

Front 286

what is methicillin?

Back 286

- narrow spectrum antibiotic

- ususally not susceptible to penicillinase, but has poor absorption

Front 287

what is ampicillin B?

Back 287

- broad spectrum antibiotic

- works on G+ and G-

- can be hydrolyzed by penicillinase

- has fair absorption

Front 288

what is amoxicillin?

Back 288

- broad spectrum antibiotic

- works well on G+ and G-

- good absorption, but susceptible to hydrolysis by penicillinase

Front 289

what are tetracycline?

Back 289

- broad spectrum antibiotic

- effective for G+ and G-, mycoplasmas, spirochetes, and rickettsias

Front 290

what are side effects of generic tetracyclines?

Back 290

Cost less but my cause:

- diarrhea

- damage to liver

- gray discoloration of teeth enamel in fetus and children

- skin reactions to sunlight (photosensitization)

Front 291

what is chloramphenicol?

Back 291

- very potent broad spectrum antibiotic

- functions by blocking peptide bond formation and hence proteinsynthesis

- originally isolated from Streptomyces venezwelae, now produced chemically

Front 292

why is chloramphenicol use restricted?

Back 292

- because very toxic to humans

- side effects include aplastic anemia

- generally given only for life threatening diseases and should neer be given in high doses

Front 293

what is erythromycin?

Back 293

- broad spectrum antibiotic

- relatively low toxicity

- alternative to penicillin resistant G+ bacteria

- blocks protein synthesis by attaching to ribosomes

Front 294

what is vancomycin?

Back 294

- narrow spectrum antibiotic

- works well for G+ bacteria

_ very toxic and hard to administer, hence generally restricted to life threatening infections

Front 295

what is clindamycin?

Back 295

- broad spectrum antibiotic

- very toxic causing gastrointestinal problems, hence has limited use

Front 296

what are some common fungi infections that humans get?

Back 296

- candida albicans

- epidermophyton

- pneumocystis carinii

Front 297

what is candida albicans?

Back 297

- yeast which causes superficial candidiasis, yeast infections in women, thrush, intestinal candidiasis

Front 298

what chemicals control candida albicans?

Back 298

- Ketoconazole

- nystatin (topical)

Front 299

what is epidermophyton?

Back 299

- fungus that causes athlete's foot

Front 300

what chemical treats epidermophyton?

Back 300

- miconazole (topical)

Front 301

wha is pnemocystis carinii?

Back 301

- yease which can cause pneumonia

- one of the common infections found in AIDS patients

Front 302

what chemical treats pneumocystis?

Back 302

- SxT

- pentamidine

Front 303

what is entamoeba histolytica?

Back 303

- amoeba that is common cause of amebiasis

Front 304

what chemical treats entamoeba histolytica?

Back 304

- metronidazole

- tetracycline

- paromomycin

Front 305

what is giardia lamblia?

Back 305

- causative agent of giardiasis

Front 306

what chemical is used to treat giardia lamblia?

Back 306

- quinacrine

- metronidazole

Front 307

what is plasmodium?

Back 307

- agent that causes malaria

- one of the most serious diseases in world today

Front 308

what is the chemical that treats plasmodium?

Back 308

- chloroquine

- primaquine

- quinine

Front 309

what is toxoplasma gondii?

Back 309

- organism that cuases toxoplasmosis

Front 310

what is the chemical that treats toxoplasma gondii?

Back 310

- primethamine

- sulfadiazine

Front 311

what is trichomonas vaginalis?

Back 311

- parasite that causes trichomoniasis

Front 312

what chemical is used to treat trichomonas vaginalis?

Back 312

- metronidazole

Front 313

what is herpesvirus?

Back 313

- virus that causes genital herpes, oral herpes, and shingles

Front 314

what chemical is used to treat herpevirus?

Back 314

- acyclovir/vidarabine

- ganciclovir

Front 315

what are treatments used for HIV?

Back 315

- AZT

- DDI

- DDC

- D4T

- protease inhibitors

Front 316

what are plasmids?

Back 316

- extrachromosomal circular DNA molecules

- ususally not essential for survival of organism

Front 317

where are plasmids found?

Back 317

- mostly in bacteria

- may be 1 - 5% of the total chromosomal DNA

Front 318

what do plasmids have a resistance to?

Back 318

- encode antibiotic resistance

- some resistance to heavy metals and cell toxins