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BIOL2265 Fundamentals Of Microbiology > 1. Introduction and Review > Flashcards

1. Introduction and Review Flashcards

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1
Q

Microbiology is the study of

A

Microbes

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2
Q

Microbes are

A

living organisms that are too small to be observed by the naked eye.

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3
Q

what is required for the study & observation of microbes.

A

Microscopes

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4
Q

A bacterium may weigh approximately

A

1x10^-11g

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5
Q

collectively microbes constitute about what % of the earth’s biomass?

A

60%

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6
Q

Microbes on earth for almost

A

4 billion years

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7
Q

Microbes Impacts

A

environment and higher life forms

there are Extremely high microbial numbers and diversity on earth

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8
Q

thereare Trillion of microbe Species on Earth with 5 million trillion trillion or 530 (5,000,000,000,000,000,000,000,000,000,000)

A

bacterial cells

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9
Q

Human body has ~3.0 X 10^ 13 cells and how many bacterial cells?

A

Human body has ~3.0 X 10^13cells and 3.8 X 10^13 bacterial cells

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10
Q

Microbes play a critical role in state of

A

health

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11
Q

Rhizosphere may contain >10 billion bacteria per

A

per gram of soil

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12
Q

Microbiological processes in the rhizosphere, phyllosphere and within plant impact tremendously on

A

health and productivity of plants

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13
Q

What are the theories of the origin of life on earth? (5)

A

1) Primordial soup theory

2) clay theory

3) spontaneous generation theory

4) pansermia

5) Directed Panspermia

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14
Q

4600 millions of years ago

A

planet earth formed

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15
Q

4300 - 3800 millions of years ago

A

indirect evidence of life on earth

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16
Q

3500 - 3400 millions of years ago

A

microbial life present evidenced by stromatolites

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17
Q

2800 - 2400 millions of years ago

A

cyanobacteria capable of oxygen evolving photosynthesis

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18
Q

2000 - 1800 millions of years ago

A

oxygen begins to accumulate in the atmosphere
evolution of eukaryotes

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19
Q

1400 millions of years ago

A

microbial assemblages of relatively large unicells

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20
Q

800 - 700 millions of years ago

A

rock deposits containing about 20 different taxa of eukaryotes, including probable protozoa and filamentous green algae

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21
Q

640 millions of years ago

A

oxygen reaches 3% of present atmospheric level

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22
Q

650 - 570 millions of years ago

A

the oldest fossils of multicellular animals, including primitive arthropods

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23
Q

570 millions of years ago onwards

A

the first evidence of plentiful living things in the rock record

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24
Q

400 millions of years ago onwards

A

development of the land flora

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25
Q

200 millions of years ago

A

mammals, flowering plants, social insects appear

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26
Q

The science of classification is known as

A

taxonomy

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27
Q

Each specific group or category used in classification is known as a

A

TAXON (plural TAXA)

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28
Q

Who was credited with founding the science of taxonomy

A

Carolus Linnaeus (1707-1778), the 18th century Swedish botanist

Linnaeus devised the binomial nomenclature system that is still used today to name organisms

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29
Q

the 5 kingdom classification systems

A
  1. Kingdom of protists (protozoans, algae)
  2. kingdom of prokaryotes / monerans (bacteria)
  3. kingdom of fungi (mushrooms, yeasts, mold)
  4. kingdom of plants (trees, fern, moss)
  5. kingdom of animals (insects, earthworm, sponge etc)
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30
Q

Proposed by Woese (1990) that a taxonomic category called DOMAIN placed above the level of

A

KINGDOM

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31
Q

taxonomic category called DOMAIN placed above the level of KINGDOM Based largely on

A

ancestral relationship derived from molecular sequence data.

Proposal spurred on by the discovery and study of organism representing a different cell type – archaeobacteria.

All living organisms evolve from a UNIVERSAL COMMON ANCESTOR

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32
Q

All living organisms evolve from a

A

UNIVERSAL COMMON ANCESTOR

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33
Q

The Cell Theory, formulated by Schleiden & Schwann, states that

A

cells are the fundamental units of all living organisms

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34
Q

All living organisms are classified as either

A

prokaryotic or eukaryotic

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35
Q

Prokaryotic

A

a combination of the Greek words pro (before) and karyon (nucleus).

These cells therefore lack a nucleus and other membrane-bound organelles

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36
Q

Eukaryotic

A

a combination of the Greek words eu (true) and karyon (nucleus).

These cells therefore contain a true membrane-bound nucleus as well as a host of membrane-bound organelles

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37
Q

DIAGRAM OF PROKARYOTIC CELL STRUCTURE

A
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38
Q

DIAGRAM OF EUKARYOTIC CELL STRUCTURE

A
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39
Q

Size of cells in Prokaryotes and Eukaryotes

A

Prokaryotes are smaller- typically 0.2-2.0 um in diameter
Eukaryotes are bigger - typically 10-100 um in diameter

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40
Q

membrane enclose organelles in Prokaryotes and Eukaryotes

A

absent in prokaryotes and present in eukaryotes (eg- lysosomes, golgi complex, endoplasmic reticulum, mitochondria and chloroplasts.

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41
Q

Flagella in Prokaryotes and Eukaryotes

A

Prokaryotes flagella consists of two protein building blocks

Eukaryotes flagella is complex and consists of multiple microtubules

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42
Q

glycocoalyx in Prokaryotes and Eukaryotes

A

prokaryotes - present as a capsule or slime layer

Eukaryotes- present in some cells that lack a cell wall

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43
Q

Cell wall in Prokaryotes and Eukaryotes

A

Prokaryotes - usually present; chemically complex (typically bacterial cell wall includes peptidoglycan

Eukaryotes - when present, chemically simple

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44
Q

Plasma membrane in Prokaryotes and Eukaryotes

A

Prokaryotes- plasma membrane has no carbohydrates and generally lacks sterols

Eukaryotes - plasma membrane has sterols and carbohydrates that serve as receptors

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45
Q

Cytoplasm in Eukaryotes

A

Eukaryotes - cytoskeleton; cytoplasmic streaming

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46
Q

Ribosomes in Prokaryotes and Eukaryotes

A

Prokaryotes - smaller size ribosomes

Eukaryotes - larger size; smaller size in organelles

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47
Q

Chromosome (DNA) in Prokaryotes and Eukaryotes

A

Prokaryotes - chromosomes usually single circular chromosome; typically lacks histones

Eukaryotes - multiple linear chromosomes with histones

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48
Q

Cell Division in Prokaryotes and Eukaryotes

A

Prokaryotes - Cell division by binary fission

Eukaryotes - cell division involves mitosis

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49
Q

Sexual Recombination in Prokaryotes and Eukaryotes

A

Prokaryotes - no sexual recombination; only transfer of DNA fragments only

Eukaryotes - sexual recombination involves meiosis

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50
Q

The prokaryotes comprise the domains

A

Archaea and Bacteria

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51
Q

How are the two domains distinguished from each other?

Archaea and Bacteria differ primarily in the following characteristics

A

Cell Wall
Membrane Lipids
Antibiotic Sensitivity
First Amino Acid in Protein Synthesis

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52
Q

There are three (3) major groups of Archaea recognized:

A

Methanogens

Extreme Halophiles

Extreme Thermoacidophiles

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53
Q

Extreme halophiles

A

Generally obligate aerobes

Thrive in highly saline environments such as the Dead Sea, the Great Salt Lake & surfaces of salt-preserved foods

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54
Q

Extreme halophiles Generally obligate

A

aerobes

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55
Q

Extreme halophiles thrive in

A

highly saline environments such as the Dead Sea, the Great Salt Lake & surfaces of salt-preserved foods

56
Q

Extreme thermoacidophiles

A

Optimum growth temperatures usually exceed 80°C

They possess heat-stable enzymes known as extremozymes

Usually colonise hot-springs, hydrothermal vents, etc

57
Q

Extreme thermoacidophiles optimum growth usually exceed

A

80°C

58
Q

Extreme thermoacidophiles possess heat-stable enzymes known as

A

extremozymes

59
Q

Diameter of bacteria

A

Bacteria are typically between 0.5 – 2.0µm in diameter

Human red blood cells measure at about 7.5µm in diameter

60
Q

Human red blood cells measure at about

A

7.5µm in diameter

61
Q

Bacteria have a large surface-to-volume ratio because of

A

Their small size.

The large surface-to-volume ratio of bacteria means that no internal structure is far from the cell surface allowing rapid access to nutrients from the exterior

62
Q

Bacteria reproduce by

A

binary fission

63
Q

Bacteria are classified according to a number of different criteria:

A

Morphology
Staining
Nutrition
Growth Characteristics
Physiology
Biochemistry
Genetics
Serology
Phage typing
rRNA sequencing
Protein electrophoretic profiles

64
Q

Bacteria show a variety of different shapes, however three basic shapes exist

A

Spherical
Rod-like
Spiral

65
Q

Coccus bacteria are what shape

A

Spherical

66
Q

Bacillus

A

rod shaped

67
Q

Spirillium

A

Spiral-shaped

68
Q

Coccobacillus shape are

A

Short rods (intermediate between coccus and bacillus)

69
Q

Vibrio

A

comma shaped

70
Q

Spirochete

A

Corkscrew-shaped

71
Q

pleomorphism.

A

when bacteria demonsrate minor variations in shape within a single species, however some species show major variations in morphology

72
Q

After cell-division bacteria adopt different cellular arrangements:

A

Diplococci – bacteria remain in pairs after dividing

Streptococci – bacteria remain attached in a chain-like pattern

Tetrads – bacteria divide in two planes and remain in groups of four

Sarcinae – bacteria divide in three planes and remain in groups of eight

Staphyllococci – bacteria divide in multiple planes and remain in clusters

73
Q

Diplococci

A

– bacteria remain in pairs after dividing

74
Q

Streptococci

A

bacteria remain attached in a chain-like pattern

75
Q

Tetrads

A

bacteria divide in two planes and remain in groups of four

76
Q

Sarcinae

A

bacteria divide in three planes and remain in groups of eight

77
Q

Staphyllococci –

A

bacteria divide in multiple planes and remain in clusters

78
Q

Staining involves

A

colouring the cells with certain dyes that emphasize different features and cellular structures

79
Q

before staining cells must be

A

fixed to the slide

80
Q

Stains are usually

A

organic salts comprising negative and positive ions, one of which is coloured

81
Q

Basic dyes are dyes in which

A

the positive ion is coloured

82
Q

Acidic dyes are those in which

A

the negative ion is coloured

83
Q

Three basic staining techniques are used to classify and identify bacteria:

A
  • Simple Staining
  • Differential Staining
  • Special Staining
84
Q

Simple Staining are either

A

aqueous or alcohol solutions of a single basic dye

85
Q

the purpose of simple staining is to

A

visualise the entire microorganism making cellular structure and morphology identifiable

86
Q

what chemical additive is usually added to simple staining

A

A chemical additive called a mordant is usually applied to:

Intensify the stain
Increase the affinity of the stain for the specimen
Act as a coating

87
Q

Examples of simple stains include

A

crystal violet,
methylene blue &
safrinin

88
Q

Differential Staining have the advantage of distinguishing between

A

between different types of bacterial cells since they react variably

89
Q

Multiple dyes are used in differential staining (the first dye is used to

A

create the primary stain and a subsequent counterstain is performed using another dye

90
Q

The two most common differential stains used for bacterial preparations are:

A

The Gram stain
The Acid-fast stain

91
Q

The Gram Stain technique is used to

A

distinguish between two main groups of bacteria and is based on the nature of bacterial cell walls.

92
Q

Gram-positive bacteria have

A

cell walls comprising a thick layer of peptidoglycan.

93
Q

Gram-negative bacteria have

A

cell walls comprising a thin layer of peptidoglcan sandwiched between the plasma membrane and an outer membrane. (inter-membrane space is known as the periplasm).

94
Q

Diagram of gram positive bacteria

A
95
Q

Diagram of gram negative bacteria

A
96
Q

difference between gram positive and negative bacteria diagram

A
97
Q

the gram staining procedure

A
  1. crystal violet (20 seconds)
  2. wash (2 seconds)
  3. grams iodine (1 minute)
  4. de-colorize with alcohol (until solvent flows colorlessly)
  5. wash (2 seconds)
  6. safranin (20 seconds)
  7. wash (2 seconds)
  8. blot dry
98
Q

diagram colour changes that occur at each step in the gram staining process

A

no colour change for heat fixed cells

colour change for crystal violet and grams iodine

gram positive have a colour change with alcohol

while gram negative is colourless

with safranin gram positive keeps colour change and gram negative turns into a different colour

99
Q

The Acid-fast Stain is Used to

A

observe bacteria with high lipid content in cell wall eg Mycobacterium

100
Q

diagram of acid fast bacteria

A
101
Q

The Acid-fast Stain is Mainly used to identify bacteria in the genus Mycobacterium

A

bacteria in the genus Mycobacterium

102
Q

The acid-fast stain makes use of the dye

A

arbol-fuchsin which binds strongly to lipids in the cell wall of these and related bacteria

103
Q

how does the acid fast stain work

A

The acid-fast stain makes use of the dye carbol-fuchsin which binds strongly to lipids in the cell wall of these and related bacteria

The fixed bacterial smear is washed with carbol-fuchsin and heated for several minutes to allow penetration into the cells

After cooling, acid alcohol is used to decolourise cells that are not acid-fast and therefore cannot retain the dye

104
Q

Acid-fast cells are able to retain

A

the red dye since carbol-fuchsin is more soluble in the waxy lipid components of the cell wall than in alcohol

105
Q

Counterstaining with methylene blue allows visualisation of

A

non-acid-fast bacteria

106
Q

what allows visualisation of non-acid-fast bacteria

A

Counterstaining with methylene blue

107
Q

Special Stains are stains that are

A

very specific and used to identify certain features of microbial cells

108
Q

Examples of special stains include:

A

Capsule staining- mostly use of negative staining techniques
Flagella staining
Endospore staining

109
Q

NEGATIVE STAINING can be used to

A

detect the presence of diffuse capsules surrounding bacteria

110
Q

negative staining uses acidic stains such as

A

negrosin or India ink

111
Q

Since these negative stains are negatively charged they

A

cannot penetrate the cells
The surface of bacterial cells is negatively charged

The unstained cells will be easily discernible against the coloured background

112
Q

advantages of negative staining

A

No fixing required
Enables visualisation of bacteria that are difficult to stain

113
Q

diagram of endospore staining - process of sporulation in bacillus

A
114
Q

in ENDOSPORE STAINING The spore stain uses

A

two different reagents

115
Q

Typical staining procedures do not work for endospore staining due to

A

the impervious nature of the spore coat
Malachite green is applied to the bacterial smear and heat is applied

116
Q

How is endospore staining done

A

Malachite green is applied to the bacterial smear and heat is applied

Both the spore as well as the cell pick up the green stain

Tap water is used as a decolourizing agent, however the endospore retains the green stain since the stain does not have a strong affinity for the vegetative cell components

Safrinin is used as a counterstain

117
Q

diagram of the bacterial growth curve

A
118
Q

bacterial growth curve is

A

a graph indicating the growth of a bacterial population over time

During batch culture, a typical bacterial growth curve shows five distinct phases of growth:

lag phase, the delay before the start of exponential growth;

exponential phase, where cell division proceeds at a constant rate;

stationary phase, when conditions become unfavorable for growth and bacteria stop replicating

death phase, when cells lose viability; and, finally, long-term stationary phase, which can extend for years

119
Q

what is the primordial soup theory

A

the primordial soup contained small organic molecules (monomers) and complex organic molecules (polymers) formed from inorganic materials in the primitive atmosphere.

120
Q

what is clay theory

A

A theory that is based on the fact that growing crystals are able to pass on traits to new crystal generations, and that clay crystals may have acted as precursors to genetic genetic material

121
Q

examples of microbes that can be seen

A

mushrooms

122
Q

endospores are bacteria but NOT

A

Fungi

endospores are resistant structures produced by gram positive bacteria

123
Q

spontaneous generation theory

A

aristotle concept that all life on earth originated spontaneously from inorganic matter

124
Q

organisms that are considered microbes

A

fungi
bacteria
microscopic algae
nemotodes
virues
protozones
parasites
virolos
satelite viruses

125
Q

pansermia theory

A

all life originated from the comits that crashed on earth

126
Q

direct pansermia

A

crashed onto earth- directed by some intelligent being

127
Q
A
128
Q

which experiment disproved the spontaenous generation theory

A

meat in test tube

129
Q

what type of reaction was used for energy by the earliest microorganisms

A

anaerobic because oxygen was not present in the atmosphere (it was present in the rocks)

Chemotrophic respiration under anaerobic conditions- the earth was largely inorganic at that time

130
Q

the earliest photosynthetic organisms were using

A

sulfur compounds

131
Q

what were the electron donors used by the earliest photosynthetic micoorganisms on earth

A

hydrogen and sulfur compounds but later on cyanobacteria

so now water is used as a donor which allowed oxygen to accumulate into the atmosphere

132
Q

with simple staining, if stained with crystal violet all the cells would appear

A

purple

133
Q

with simple staining, if stained with safronin all the cells would appear

A

pink

134
Q

simple staining does not

A

differentiate between the different types of bacterial cells.

135
Q
A

BIOL2265 Fundamentals Of Microbiology (5 decks)

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