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BI276 > week 3,4,5,6 cont.. > Flashcards

week 3,4,5,6 cont.. Flashcards

1
Q

-acidic dye

A

chromophore is the negative ion

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2
Q

pH can alter staining effectivness since

A

nature and degree of charges on cell components change with pH

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3
Q

Fixation causes the cells to

A

-kills the cell

-solidifies cellular consistuents

-avoids creation of artifacts

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4
Q

Staining

A

-increases visibility

-increaes differece in refractive index

-emphasizes cell differences through light absorption

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5
Q

Fimbriae

A

-occur at bacterial cell poles or evenly distributed over entire cell surface

-few or servers hundred per cell

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6
Q

Staining

A

-increases visibility

-increase difference in refractive index

-emphasizes cell differences through light absorption

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7
Q

Decolourization:

A

tests degree of attachment of dye to cell substrate

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8
Q

application of counter stain

A

-emphasizes difference between cells that retained primary and decolourized cells.

-must not replace original stain.

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9
Q

simple stain

A

-alcohol solution of single basic dye

-highlights entire microorganism to visualize

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10
Q

-Differential stain

A

-react differently with different kinds of bacteria

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11
Q

Gram stain:

A

1-primary stain applied to heat fixed smear

2-rinse primary stain

3-decolourize

4-counterstain

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12
Q

gram negative:

A

-non-cluster, cell wall structures are different. They are vasatile and flexible, stay pink under differential stain

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13
Q

gram positive:

A

-cluster, stay purple

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14
Q

Acid fast stain:

A

-binds only to bacteria with a waxy cell wall

-used for genus

-carbolfuchsin applied to fixed smear then heated, cooled and rinsed

-acid-alchol decolourizes non acid-fast bacteria.

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15
Q

Negative stain

A

-used for capsule staining

-colloidal suspension of India ink or nigrosin provide dark background

-bacteria stained with a simple stain but capsular material will not retain bio dye

-capsules appear as halos.

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16
Q

Endospore stain:

A

-schaeffer-fulton endospore stain

-primary stain is steam heated for 5 mins

-after rinishing, safranin applied as a counterstain

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17
Q

Flagella stain:

A

-the structure requires layers of stain to be built upon it

-important in diagnostics of certain bacterial species.

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18
Q

Synthetic reactions:

A

result in the formation of a particular product from reactant

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19
Q

Decomp reaction

A

: bonds are broken resulting in smaller molecules.

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20
Q

exchange reactions:

A

part synthesis and part decomposition.

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21
Q

endergonic reaction:

A

absorbs more energy than it releases

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22
Q

excgonic reaction:

A

releases more energy than it absorbs or requires

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23
Q

inorganic compounds:

A

small sturcturally simple

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24
Q

Organic compounds:

A

Always contain carbon, hydrogen ; more sturcutrally complex.

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25
pH
-most microorganisms grow best in pH ranges neutrality -Natural buffers help maintain a constant pH in the organism’s micro- enviroment -fungi prefer more acidic environment
26
Acidophile-
bacterium which grows below pH 4
27
alkaliphile=
organism growing best at high pH
28
carbs:
contain carbon, hydrogen and oxygen and perform a number of major functions in living systems including cell wall structures in bacterial cells. -monosacchidrides, diaccharides and polysaccharides
29
lipids:
-essential to the sturcture and function of membranes -amphipathic property makes them ideal permeability barriers -in membrane strucutre it’s important to maintain a specific viscosity to provide both support and allow nutrient passage.
30
Phospholipids contians:
-consistent of glycerol, two fatty acids and a phosphate group polar head = phosphate group + glycerol non-polar tail= fatty acid tail
31
Phospholipid membranes
-provides a barrier which seperates intracellular contents form the aqueous enviroment
32
Proteins- -
organic molecules containing C,H,O and N -specific proteins cna function as enzymes which catalyze bio reactions within the cell, or toxins which may promote disease.
33
Microbial diversity
-diversity evident through differences in cell shape, shape, physiology….
34
How much characteristics of living systems
6
35
metabolism-
uptake of nutrients from the enviroement, their transformation within the cell and elimination of wastes
36
-reproduction-
chemicals from the enviroment are turned into new cells under the direction of pre existing cells
37
-differentiation-
formation of new cell structure such as a spore, usually as part of a cellular life cycle.
38
-communication
-cells communicate or interact primarily by means of chemicals that are released or taken up
39
-movement-
Living organisms are often capable or self propulsion
40
-evolution-
cells contain genes and evolove to display new biological properties, phylogentic trees show the evolutionary relationships amongst species.
41
Metabolic diversity
-microorganisms can be classified metabolically according to a nutrientional pattern -baed on energy source: -
42
-chemotroph
-inorganic or organic compounds for energy
43
phototroph
-light is primary source
44
45
46
47
Photoautotrophs:
-use light for energy carbon dioxide as C source -photosynthetic bacteria
47
Autotroph
=CO2
48
Hetrotroph
=organic carbon source
49
Photoheterotrophs:
-use light energy and organic C source -green nonsulfer bacteria, purple nonsulfer bacteria
50
Chemoautotrophs:
-use inorganic compounds as an energy source and enviroment carbon dioxide as primary C source -ammonia, iron and nitrite
51
Chemoheterophs
-energy and carbon sources often the same organic compound -glucose
52
Smallness:
-advantages to bring small reflected by the larger surface area relative to cell volume compared to large cells -the surface area becomes a function of the radius of the phere where: -S/V=3/r
53
Cytoplasmic Membrane
-also called inner or plasma membrane -lies inside cell wall and encloses the cell cytoplasm seperating inside of the cell from the enviroment -composed primarily of phopholipids and proteins -phosphopipid bilayer -peropheral and integral proteins -arrangement of proteins and photopholipids, called the fluid mosaic model. -Fosil lipid bilayer
54
Archaeal Membranes:
-lipids contain ether linkages rather than ester linkages -fatty acid side chains replaced by isoprene -lipid monolayer structure rather than bilayer
55
Membrane function:
-forms a selective barrier for materials to enter or exit the cell -catalysis of speciic reactions occurs on or at the membrane -site of energy conservation in the cells
56
-passive processes involve movment with a concentration gradient and requring no energy
involve movment with a concentration gradient and requring no energy
57
Osmotic pressure-
Pressure required to stop the osmotic flow of water across the membran
58
actiove processes
involve movement against a conc gradient, requiring the expenditure of energy.
59
Active transport processes:
-in low nutrient environments, active processes are required -energy in the form of ATP, proton motive force or high energy compound -Dependent on transporter proteins in the plasma membrane.
60
Transport proteins:
-assist in accumulating solutes inside the cell against a concentration gradient -Necessary in order for the cell to accumulate nutrient levels higher than those found in nautre
61
Membrane-transporting systems:
1-involve only a membrane-spanning component 2-involve a periplasmic binding 3-Involve a series of proteins that cooperate to mediate the transport event
62
sympoter :
protein transports a substance along w another substance
63
antipoter :
protein transports a substance in one direction and second substance in the opposite direction.
64
Group translocation:
-occurs in prokaryotes -substance is chemically altered during transport across the membrane -altered substance is impeccable to the ell membrane -acquires substances present in low conc -requires high energy phosphate compounds
65
ABC syestem:
-periplasmic binding protein dependent transport -proteins within periplasm of gram negative bacteria mediate the transport event -hydrolysis of ATP supples required energy -more than 200 different types identified in prokaryotes
66
Bacterial cell Wall Structure
adjacent rows of peptidoglycan linked by polypeptide chains containing tetrapeptide side chains -Parallel tetrapeptide side chains are bonded directly or linked by cross bridges.
67
G+ve cells walls______, whereas, G-ve cell walls otherwise contain ________.
also have severals layers of peptidoglycan; thin layers of peptidoglycan and are not as rigid
68
Outer membrane porins
-proteins embedded in the OM which serve as channels to allow the passage of essential molecules such as nucleotides, dirracharides, peptides, amino acids
69
-G-ve cell walls contain few layers of peptidoglycan but include an outer membrane peptidoglyan.
-G+ve cell walls typically contain several layers of peptidoglycan, G-ve cells walls contain a thin peptidoglycan layer.
70
Gram-positive and Gram-negative cells walls:
-G-ve periplasm contains high concentrations of degradative enxymes and transport proteins -prokaryotic cell walls generally susceptible to the action of lysozyme, which attacks the peptidoglycan backbone, and certain antibiotics such as penicillin.
71
Gram negative outer membrane:
-composed of lipopolysaccharides (LPS), lipoproteins nad phospholipids
72
-outer membrane porins….-
-proteins embedded in the Outer membrane which serve as channels to allow passage of essential molecules such as neucleotide
73
Inclusions:
reserve deposits found in prokaryotic cells -include metachromatic granules, polysaccharide grandules, lipid inclusions, sulfer granul
74
Endospores
-specialized resting cell produced by certain positive bacteria -environmentally tolerant to heat low toxic chemicals and radiation
75
Endospore formation
-formed within the vegetative cell -usually initiated by a lack of available nutrients or environmental stress -spore septum forms initially-isolating replicated chromosome and a portion of the cytoplasm -septum thickens into a membrane and the forespore is formed. -Layers of peptidoglycan are laid down after which protein layers form creating a spore coat -only the most important bits are retained
76
-germinatation=
return to the vegetative state as a result of physical or chemical damage to the endospore coat.
77
Characteristics of endospores
-1) no means of reproduction -2) resistant to adverse contiions -3) compostion and activity different form vegetative cell. -4 no metabolic activty -5) low water content -6) low calcium ions.
78
Glycoclyx:
-geleatinous polymer composed of polysaccharide, polypeptide -can be important virulence factor
79
Lipopolysaccharides (LPS)
are important outer membrane components of gram-negative bacteria. They are large amphipathic glycoconjugates that typically consist of a lipid domain
80
Gram negative bacteria contains two pairs
s of rings in the basal body, outer pair encoded to the cell wall and inner pair anchored to the plasma membrwn
81
-Continpius
movement in one direction is called a run or swim which can be interrupted by an abrupt change in direction called a tumble.

BI276 (4 decks)

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