MICROPENIS Flashcards

1
Q

benign

A

The vast majority of microbes are “benign”. Most are either directly or
indirectly beneficial to us.
*A few are pathogenic
*They decompose organic waste
*They are producers in the ecosystem (by photosynthesis)
*Help in animal digestion and vitamin production
*Commercial uses include chemicals, therapeutic drugs and more

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2
Q

Luis Pasteur

A

He started off by demonstrating the presence of microbes in the air. He used a cotton plug that caught germs to filter the air in order to do this. The microbes were then examined under a microscope, and he found that many of them matched the descriptions made by researchers who had previously investigated broths. The sterilized soup that Pasteur placed the cotton plug into became cloudy as a result of the growth of these bacteria. In particular, Pasteur demonstrated that sterile broths maintained their sterility even when exposed to air in specially designed swan-necked flasks. Airborne microorganisms gathered in the flask neck bends rather than reaching the soup. The broth could only support microbial growth when the flasks were tilted. Pasteur’s simple and elegant experiments refuted the assertions that broths or unheated air had the “vital power” necessary for spontaneous creation. They gave birth to the biogenesis theory, which states that live things are created from non-living ones.

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3
Q

Describe two microbial activities essential to life and three that
make our lives more comfortable.

A

Essential activities—(1) Conversion of nitrogen of the air into a form that is useable by plants and animals, and (2) replenishment of O2 in the atmosphere by photosynthetic microorganisms. Non-essential activities—(1) Synthesis of many products used in every day life (amino acids, vitamins, etc), (2) involvement in food and beverage production, and (3) degradation of environmental pollutants

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4
Q

Describing three factors that cause certain infectious diseases to become more
common.

A

poor sanitation, unsafe food and water, and poor hygiene

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5
Q

Organic molecules

A

*Carbohydrates
*Lipids
*Proteins
*Nucleic Acids

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6
Q

Chemistry of life

A

Carbon, hydrogen, Phosphorous, sulfur, oxygen, and nitrogen (these six elements make up 96% of our mass).

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7
Q

Chemical bonds

A

The forces that attract atoms to each other in compounds

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8
Q

Ionic bond

A

the attractive electrostatic force between a negative ion and a positive ion

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9
Q

covalent bond

A

Atoms that do not have filled valence shells may share pairs of valence electrons

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10
Q

Carbohydrates (monomer and Polymer)

A

Monosaccharide (monomer) polysaccharide (polymer)

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11
Q

Proteins (monomer and Polymer)

A

Amino acids (monomer) polypeptide (polymer)

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12
Q

Lipids (monomer and Polymer)

A

Fatty acid, glycerol (monomer) Lipid (polymer)

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13
Q

Nucleic acids (monomer and Polymer)

A

Nucleotide (monomer) Nucleic acid (polymer)

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14
Q

Monosaccharides

A

Glucose, Fructose, Galactose

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15
Q

Disaccharides

A

Maltose, Lactose, Sucrose

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16
Q

Polysaccharides

A

Starches, Fibers, Glycogen

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17
Q

Lipids

A

Phospholipids, triglycerides, sterols

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18
Q

Hydrogen bonds

A

are weak bonds formed when a hydrogen atom in a polar molecule is attracted to an electronegative atom in the same or another polar molecule.

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19
Q

Prokaryotes

A

-lack membrane
bound organelles
-lack membrane
a bound nucleus
-Archaea
-Bacteria

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20
Q

Eukaryotes

A

-have several membrane bound organelles.
-have a membrane bound nucleus
-much larger in comparison to prokaryotes in the
order of 100X
-Eukarya

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21
Q

Viruses

A

consist of DNA or RNA, surrounded by a protein coat. They are obligate intracellular parasites and collectively infect of all forms of life.

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22
Q

Viroids

A

consist of only RNA, with no protein coat. Like viruses, they are obligate intracellular agents. Viroids cause a number of plant diseases.

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23
Q

Prions

A

consist only of proteins. Prions are simply misfolded versions of normal cellular proteins found in the brain.

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24
Q

cytoplasmic membrane

A

is a thin, delicate structure that
surrounds the cytoplasm and defines the boundary of the cell.
The membrane is selectively permeable. Molecules move through the membrane by a variety of mechanisms

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25
Q

Simple diffusion

A

a passive process in which molecules move from a region of high
concentration to one of low concentration, until equilibrium is reached.

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26
Q

Osmosis

A

a passive process in which water moves across the cell membrane down its
concentration gradient from high water concentration (low solute concentration) to
low water concentration (high solute concentration).

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27
Q

facilitated diffusion

A

(a passive process in which molecules cross the
membrane via transport proteins called permeases or carriers),

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28
Q

active transport

A

(that moves molecules against their concentration gradient
and thus requires energy expenditure; energy is provided by ATP or the
proton motive force)

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29
Q

Diplococci

A

two cocci cells stuck together

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30
Q

Streptococci

A

describes multiple chains

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31
Q

Staphylococci

A

produce grape-like
clusters

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32
Q

Gram-positive wall

A

thick peptidoglycan layer and there are teichoic acids in
the wall but there is no outer membrane.
(Bacteria stain purple if positive)

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33
Q

The Gram-negative wall

A

has a thin layer of peptidoglycan and an outer membrane containing lipopolysaccharide (LPS).
Between the cytoplasmic membrane and the outer membrane is the periplasm.
(Bacteria stain pink if negative)

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34
Q

LPS

A

It has two components: lipid A and O antigen. O antigen
can be used to identify bacteria. Lipid A alerts the immune system to microbial invaders when present in low amounts. In high amounts however, LPS can cause shock and even death – it is an ENDOTOXIN.

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35
Q

Peptidoglycan (Murein) Structure

A

contains N-acetyl glucosamine and N-acetylmuramic acid and several different amino acids.

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36
Q

Capsules and slime layers

A

which are used by cells for attachment to surfaces, and
creating biofilms e.g. dental plaque, a biofilm on teeth. Some capsules also function to protect cells from phagocytosis.

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37
Q

Flagella

A

which are appendages composed of the protein flagellin, and are used for movement.

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38
Q

Pili

A

which are shorter and firmer than flagella and are composed of the protein pilin.
Pili called fimbriae are used for attachment to surfaces; sex pili are used in genetic exchange.

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39
Q

Chemotaxis

A

Movement towards or away
from a substance
*Positive chemotaxis: towards
the attractant
*Negative chemotaxis: away
from the attractant

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40
Q

Transport proteins

A

which function either as channels or carriers.

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41
Q

Endocytosis

A

(including receptor-mediated endocytosis) and pinocytosis, the
uptake of small molecules or drops of liquid.

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42
Q

Phagocytosis,

A

the engulfment of bacteria and debris by specialized cells

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43
Q

Exocytosis

A

the reverse of endocytosis by which debris is released from a cell

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44
Q

Electron microscopes (transmission and scanning)

A

can magnify up to 100,000-
fold and are used to examine fine details of cell structure. Information is also given on
scanning probe microscopes such as atomic force microscopes.

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45
Q

principles of light microscopy

A

magnification, resolution, refraction, and contrast.

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46
Q

Simple staining

A

a single dye is used. Typically the dye is basic and has a positive charge; it stains bacterial cells, which have many negatively charged components.

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47
Q

negative staining

A

Acidic dyes have a negative charge and are used for negative staining, in which the
background is colored, rather than the cells.

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48
Q

Differential staining

A

is used to distinguish between groups of bacteria. The most commonly used are the Gram stain and the acid-fast stain. The Gram stain differentiates between Gram-positive bacteria (which stain purple) and Gram-
negative bacteria (which stain pink).

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49
Q

Special stains

A

including the capsule stain, the endospore stain, the flagella stain, and fluorescent stains that are used in a technique called immunofluorescence.

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50
Q

Binary fission

A

Bacteria and archaea multiply by binary fission

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51
Q

Exponential

A

Cell growth is exponential

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52
Q

generation time

A

he time it takes for a generation to double is the generation time

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53
Q

biofilms

A

In nature, most microbes grow in polymer-encased communities called biofilms
- Biofilms
may be either damaging (for example, those involved in infections) or beneficial (for
example, they are used in bioremediation). The majority of bacterial infections involve
biofilms. Treatment of these infections is difficult because microbes within the biofilm often
resist the effects of antibiotics as well as the body’s defenses.

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54
Q

In the laboratory, prokaryotes are generally grown in ______

A

pure cultures

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55
Q

Pure cultures are typically obtained using the _________in which individual
_______ are isolated using __________

A

streak-plate method; colonies; aseptic technique

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56
Q

Once a pure culture has been obtained, it can
be maintained as a _________

A

stock culture

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57
Q

open system

A

nutrients are continually added and wastes are removed, so that cells are maintained in a state of constant growth.

58
Q

closed system

A

nutrients are not renewed and wastes are not renewed. The cells follow distinct stages of growth, called a growth curve.

59
Q

lag phase

A

cells are metabolically active but do not divide.

60
Q

exponential or log growth phase

A

cells divide and their numbers increase logarithmically. Cells are most sensitive to antibiotics during this time. They also produce primary and secondary metabolites during this phase, which may be commercially valuable.

61
Q

stationary phase

A

When the nutrient level in the system is too low to sustain growth, cells enter the stationary phase, and the total number of cells in the population remains fairly
constant.

62
Q

death phase

A

the number of cells in the population declines as cells die at
a constant rate.

63
Q

period of prolonged decline

A

during which most cells die, but a few are able to survive.

64
Q

Psychrophiles

A

optimum between –5°C and 15°C.

65
Q

Psychrotrophs

A

optimum between 15°C and 30°C but grow at lower
temperatures as well. Refrigeration slows growth but does not kill these
microbes.

66
Q

Mesophiles

A

optimum between 25°C and about 45°C. Pathogens, adapted to
growth in the human body, typically have an optimum between 35°C and 40°C
although some may prefer lower temperatures and grow in cooler regions of
the body e.g. M. leprae, the causative organism of leprosy.

67
Q

Thermophiles

A

optimum between 45°C and 70°C

68
Q

Hyperthermophiles

A

optimum of 70°C or greater.

69
Q

Obligate aerobes

A

have an absolute requirement for oxygen (O2). They use it
in aerobic respiration, an energy-harvesting process.

70
Q

Facultative anaerobes

A

grow better if O2 is present, but can also grow without
it.

71
Q

Obligate anaerobes

A

cannot multiply if O2 is present

72
Q

Microaerophiles

A

require low amounts of O2 (2% to 10%).

73
Q

Aerotolerant anaerobes

A

indifferent to O2. They can grow in its presence,
but do not use it to harvest energy. They are also called obligate fermenters,
because fermentation is their only metabolic option.

74
Q

neutrophiles

A

Most microbes are neutrophiles—they live and multiply within the range of
pH 5 (acidic) to pH 8 (basic), and have a pH optimum near neutral (pH 7).

75
Q

Acidophiles

A

grow optimally at a pH below 5.5.

76
Q

Alkaliphiles

A

grow optimally at a pH above 8.5.

77
Q

Water availability

A

All microorganisms require water for growth. If the solute
concentration is higher in the medium than in the cell, water diffuses out of the cell due to osmosis. This causes the cytoplasm to dehydrate and shrink from the cell wall,
a phenomenon called plasmolysis

78
Q

Microbes that tolerate high salt concentrations, up to approximately 10% NaCl, are _________

A

halotolerant

79
Q

halophiles

A

require high levels of sodium chloride.

80
Q

heterotrophs

A

use organic carbon; medically important bacteria are typically heterotrophs.

81
Q

autotrophs

A

use inorganic carbon in the form of carbon dioxide (CO2). They play a critical role in the cycling of carbon in the environment

82
Q

Phototrophs

A

harvest energy from sunlight

83
Q

chemotrophs

A

extract energy from chemicals.

84
Q

Photoautotrophs

A

use the energy of sunlight to make organic compounds from CO2 in the atmosphere

85
Q

Photoheterotrophs

A

use the energy of sunlight and obtain their carbon from organic
compounds.

86
Q

Chemolithoautotrophs

A

use inorganic compounds for energy and obtain their carbon
from CO2.

87
Q

Chemoorganoheterotrophs

A

use organic compounds for both energy and carbon.

88
Q

complex medium

A

contains a variety of ingredients such as meat juices and
digested proteins, and is used for routine purposes. Examples include blood agar, and chocolate agar.

89
Q

chemically defined medium

A

is composed of specific amounts of pure chemicals,
so its exact chemical composition is known. This type of medium is generally used
only for certain research experiments e.g. glucose-salts agar.

90
Q

Selective media

A

contain an ingredient that inhibits the growth of certain species in a mixed sample, while allowing the growth of the species of interest e.g. MacConkey
agar, which inhibits the growth of Gram-positive cells.

91
Q

Differential media

A

contain a substance that certain microbes change in a
recognizable way e.g. blood agar (showing hemolysis) and MacConkey agar (differentiating between lactose-fermenting bacteria [pink-red] and lactose-negative bacteria [colorless]).

92
Q

Direct cell counts

A

are used to determine total number of cells including living and
dead cells; examples are direct microscopic counting and cell-counting instruments such as the Coulter counter or the flow cytometer.

93
Q

Viable cell counts

A

are used to determine the number of microorganisms capable of
growing in a given set of conditions; includes plate counts, membrane filtration and most probable number.

94
Q

Biomass

A

can be correlated to cell number. Biomass can be measured by measuring turbidity or total microbial weight.

95
Q

Taxonomy order

A

Kingdom, Phylum, Class, Order, Family, Genus, Species

96
Q

NT=N0X2^N

A

NT = NUMBER OF CELLS IN POPULATION
N0 = ORIGINAL NUMBER OF CELLS IN THE POPULATION
N - NUMBER OF DIVISIONS

97
Q

Catabolism

A

is the set of chemical reactions that degrade compounds, releasing their energy. Cells capture that energy and use it to make ATP—the energy currency of the cell.

98
Q

Anabolism

A

is the set of chemical reactions that cells use to synthesize and assemble the subunits of macromolecules, using ATP for energy.

99
Q

metabolic pathway

A

The series of chemical reactions that
converts a starting compound to an end product

100
Q

Enzymes

A

drive chemical reactions; these are molecules (usually
a protein) that function as biological catalysts, speeding up the conversion of one substance, the substrate, into another, the product, by lowering the activation energy—the energy it
takes to start a reaction

101
Q

co-factor

A

Some enzymes require the assistance of an
attached non-protein component called

102
Q

denature

A

losing their characteristic 3D shape.

103
Q

Glycolysis

A

converts glucose to pyruvate and generates 2 ATP (net) by substrate-level phosphorylation, 2 NADH + 2 H+, and six different precursor metabolites

104
Q

pentose phosphate cycle

A

is an alternative break down glucose, and generates
various amounts of NADPH + H+, and two different precursor metabolites

105
Q

transition step

A

links glycolysis or the pentose phosphate pathway to the TCA
cycle; it is repeated twice to oxidize two molecules of pyruvate to acetyl-CoA, and generates 2 NADH + 2 H+ and one precursor metabolite

106
Q

TCA cycle

A

is repeated twice to incorporate two acetyl groups and generates 2 ATP by substrate-level phosphorylation, 6 NADH + 6 H+, 2 FADH2 and two different precursor metabolites

107
Q

Hydrogen bacteria

A

oxidize hydrogen gas.

108
Q

Sulfur bacteria

A

oxidize hydrogen sulfide.

109
Q

Iron bacteria

A

oxidize reduced forms of iron.

110
Q

Nitrifying bacteria

A

include two groups of bacteria; one oxidizes ammonia (forming
nitrite), and the other oxidizes nitrite (producing nitrate).

111
Q

photosynthesis

A

conversion of radiant energy into chemical energy

112
Q

carbon fixation

A

Chemolithoautotrophs and photoautotrophs incorporate carbon dioxide (CO2) into organic compounds

113
Q

Calvin cycle

A

(1) Incorporation of CO2 into an organic compound; (2)
reduction of the resulting molecule; and (3) regeneration of the starting compound.

114
Q

genome

A

The genetic material of a cell

115
Q

cell division

A

(1) replicate its DNA and (2), express its genes, which involves copying the information of DNA into RNA
(transcription) and then decoding the RNA to synthesize a protein (translation).

116
Q

DNA

A

is a double-stranded, helical structure composed of nucleotides. Each nucleotide contains a 5-carbon sugar (deoxyribose), a phosphate group, and one of four different
nucleobases (A, T, G, or C). The two strands in the DNA helix are complementary and are held together by characteristic bonding of A to T and G to C, called base pairing

117
Q

transcription

A

It involves copying a gene’s DNA sequence to make an RNA molecule.

118
Q

Translation

A

decoding of the information in mRNA to create the specified protein.

119
Q

Antigenic variation

A

random changing in the characteristics of certain surface proteins.

120
Q

Phase variation

A

is the random switching on and off of
certain genes. This can help a microbe colonize different habitats.

121
Q

constitutive

A

(synthesized continuously)

122
Q

inducible

A

(synthesized when needed)

123
Q

repressible

A

(routinely produced but synthesis
can be turned off when they are not needed).

124
Q

repressor

A

blocks transcription when it binds
to an operator

125
Q

activator

A

enhances transcription when it binds to an activator-binding site

126
Q

Inducers

A

bring about gene expression by binding either to repressors (disabling them)
or to activators (allowing them to attach to the activator-binding site).

127
Q

lac operon

A

model for gene regulation

128
Q

Carbon catabolite repression (CCR)

A

prevents transcription of the lac operon
when glucose is available

129
Q

inducer exclusion.

A

A type of CCR that prevents a carbon/energy source from being transported into the cell

130
Q

Mutation

A

changes the existing nucleotide sequence of a cell’s DNA, which is then passed on to the progeny through vertical gene transfer

131
Q

Horizontal gene transfer

A

is the movement of
DNA from one organism to another. Like mutations, the changes are then passed on to the
progeny by vertical transfer.

132
Q

auxotroph

A

mutant that requires a growth factor

133
Q

prototroph

A

A wild type organism that does not require additional growth factors

134
Q

base substitution

A

-most common mutation
-occurs during DNA synthesis when an incorrect nucleotide is incorporated.

135
Q

silent mutation,

A

the change generates a codon that translates into the same
amino acid as the original.

136
Q

missense mutation

A

results when the altered codon codes for a different amino
acid.

137
Q

nonsense mutation

A

occurs when the base substitution creates a stop codon,
resulting in a shorter (truncated) and often non-functional protein.

138
Q

Transposons

A

jumping genes, are pieces of DNA that can move from one location to another in a cell’s genome, a process called transposition.

139
Q

insertional inactivation.

A

The gene into which a transposon
jumps is inactivated by the event

140
Q

stop codons

A

UAG, UAA, UGA