Microbial Cell Flashcards
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1
Q
The ability to distinguish two adjacent objects as separate and distinct. Its determined by the wavelength of light used and numerical aperture of lens
A
Resolution
2
Q
Its the ability to make an object larger
A
Magnification
3
Q
What is the maximum magnification of microscope
A
average 2,000 X
4
Q
What is the limit of the resolution of light microscope
A
0.2 microns
5
Q
Type of microscope:
- visualizes specimen by the differences in density between specimen and surroundings
A
Bright field microscope
6
Q
How to improve contrast of in light microscope
A
Staining
7
Q
It separates bacteria into groups
A
Gram Stain
8
Q
what is the color of gram positive bacteria
A
purple
9
Q
what is the color of gram negative bacteria
A
red
10
Q
Type of microscopy:
- invented by Frits Zernike
- Phase ring amplifies differences in refractive index of cell and surroundings
- improves contrast of sample without use of a stain
- allows visualization of live samples
- resulting image is dark cells on light background
A
Phase - Contrast microscopy
11
Q
Type of microscopy:
- light reaches specimen from the sides then scatters when reaching the it
- image appears light on dark background
- excellent for observing motility
A
Dark - Field microscopy
12
Q
Type of microscopy:
- used to visualize specimens that fluoresce
- widely used in microbial ecology for enumerating bacteria in natural samples
A
Fluorescence microscopy
13
Q
Example of cells that fluoresce naturally
A
Chlorophyll
14
Q
A fluorescent dye that can stain both live and fixed cells. It is excited by ultraviolet light which makes it emit blue color
A
DAPI
15
Q
Type of microscope:
- uses electrons instead of photons to create image of cells and structures
A
Electron Microscope
16
Q
Two types of electron microscopes
A
Transmission and Scanning
17
Q
Type of electron microscope:
- electromagnets function as lenses
- its system operates in a vacuum
- High mag and res is 0.2 nm
- specimen viewed must be very thin (20-60nm) and be stained
A
Transmission electron microscope
18
Q
Type of electron microscope:
- coated with thin film of heavy metal
- electron beam scans the object
- scattered electrons are collected by detector to produce an image
- mag range is 15 X - 100,000 X
- even large specimens can be observed
A
Scanning electron microscope
19
Q
It means the cells shape
A
Morphology
20
Q
Cell morphologies:
- spherical or ovoid
A
Coccus
21
Q
Cell morphologies:
- cylindrical shape
A
Rod
22
Q
Cell morphologies:
- spiral shape
A
Spirillum
23
Q
Cell morphologies:
- has a stalk and a hypha
A
Budding and Appendaged bacteria
24
Q
Cell morphologies:
- filamentous
A
Filamentous bacteria
25
what is the size range of eukaryotic cells?
10 to >200 microns in diameter
26
What is the size range of prokaryotes?
0.2 microns to >700 microns
27
What are the advantages of small cells?
- have more surface area relative to cell volume
- supports greater nutrient exchange per unit cell volume
- tend to grow faster than larger cells
28
Its general structure is a phospholipid bilayer. fatty acids point inward and hydrophilic portions remain exposed to cytoplasm. it is
8 -10 nm wide and is embedded with protein. Stabilized by hydrogen and hydrophobic interactions
Cytoplasmic Membrane
29
Found in the outer layer of cytoplasmic membrane
Membrane proteins
30
Proteins firmly embedded in membrane
Integral Membrane protein
31
Proteins that have one portion anchored in the membrane
Peripheral Membrane proteins
32
This membrane
- has ether linkages in phospholipids in any bacteria or Eukarya
- has isoprenes instead of fatty acids
- its major lipids are diethers and tetraethers
- can exist as lipid monolayers, bilayers, or mixture
Archaeal Membranes
33
Holds transport proteins in place
Protein anchor
34
Generation of proton motive force
Energy Conservation
35
Carrier mediated transport proteins are?
- shows saturation effect
- highly specific
- highly regulated
36
3 major classes of transport systems
1. Simple transport
2. Group Translocation
3. ABC system
37
Identify which transport system is being described:
- driven by energy in the proton motive force
Simple Transport
38
Identify which transport system is being described:
- chemical modification of the transported substance driven by phosphoenolpyruvate
Group Translocation
39
Identify which transport system is being described:
- periplasmic binding proteins are involved and energy comes from ATP
ABC Transporter
40
3 possible transport events
1. Uniporters
2. Symporters
3. Antiporters
41
Its a rigid layer that provides strength to the cell wall
Peptidoglycan
42
Its a polysacharide that is composed of
- amino acids
- N-acetylglucosamine and N-acetylmuramic acid
- Lysine or diaminopimelic acid
- Corss linked differently in gram negative and positive bacteria
Peptidoglycan
43
Prokaryotes that lack cell walls
Mycoplasma - group of pathogenic bacteria
Thermoplasma - Species of archea
44
Reasons why Mycoplasma and Thermoplasma can survive without cell wall
Mycoplasma - have sterols on their cell membrane
Thermoplasma - have lipoglycans in their cell membrane
Both - live in osmotically protected habitats
45
cell wall contains how much peptidoglycan
average 10%
46
Most of cell wall composed of what?
lipopolysaccharide (LPS) layer
47
LPS layer consist of what
core polysaccharide and O-polysaccharide
48
Replaces most of the phospholipids in outer half of outer membrane
LPS layer
49
Toxic component of LPS layer
Endotoxin
50
Its the space located between cytoplasmic and outer membrane.
- average 15 nm wide
- contents have gel like consistency
- houses many proteins
Periplasm
51
Channels for movement of hydrophilic low molecular weight substances. Facilitates that entry of materials needed by the cell that by the outer membrane. Can be nonspecific and specific
Porins
52
responsible for differences in the gram stain reaction of bacteria
structural differences between cell walls of gram positive and negative Bacteria
53
Its a bacteria with no cell walls, no outer membrane, and some may lack pseudomurein.
Archean
54
A polysaccharide similar to peptidoglycan. Composed of
N-acetylglucosamine and N-acetylalosaminuronic acid. Found in cell walls of certain methanogenic Archea
Pseudomurein
55
Most common cell wall type among Archaea. Consist of interlocking protein or glycoprotein. has Paracrystalline structure. allows archea to withstand strong osmotic pressure. serves as a filter to only allow solutes of lower molecular weight. Retains proteins near the cell surface. Its resistant to lysozyme
S-Layers
56
Cell surface structures:
- a polysaccharide layers that may be thick or thin, rigid or flexible
- assist in attachment to surfaces bacterial pathogenicity
- protect agains phagocytosis
- resists desiccation - enhancing bacterial virulence
Capsules and Slime layers
57
Cell surface structures:
- filamentous protein structure
- enable organisms to stick to surfaces or form pellicles or biofilm
- enhances bacterial virulence as it assist disease process or attachment to tissue
Fimbriae
58
Cell Surface Structures:
- Filamentous protein Structure
- typically longer than fimbriae
- assist in surface attachment
- facilitate genetic exchange between cells (conjugation)
- Receptor for certain viruses
Pili
59
Cell Inclusions:
- has lipids composed of 3-18 carbons
- has glycogen
Carbon Storage polymers
60
Its a glucose polymer
Glycogen
61
Cell inclusions:
- accumulations of inorganic phosphate
Polyphosphates
62
Cell Inclusions:
- Composed of elemental sulfur stored in periplasm
Sulfur globules
63
Cell Inclusions
- composed of barium, stronitum, and magnesium
Carbonate materials
64
Cell Inclusions:
- magnetic storage inclusions (iron oxide mineral magnetite)
- allows bacterial cells to orient themselves within magnetic field. not observed in archea
Magnetosomes
65
They confer buoyancy in planktonic cells. Spindle shaped, gas filled structures made of protein. Impermeable in water.
Gas Vesicles
66
What is phytoplankton?
- organism that lives in watery environments
- plant like, produces own food
67
What is zooplankton?
- animal like
- consumes other organisms
68
Molecular structure of gas vesicles
- composed of two proteins GvpA (water tight vesicle shell) and GvpC (strengthen the shell of the gas vesicle)
- functions by decreasing cell density
69
They are highly differentiated cells resistant to heat, harsh chemicals, and radiation. The dormant stage of bacterail life cycle. Ideal for dispersal via wind, water, or animal gut. Present only in some gram positive bacteria.
Endospores
70
Endospore structure
- structurally complex
- contains dipicolinic acid
- enrinched in Ca2+
- Core contains small acid soluble spore proteins (SASP)
71
Its a complex series of events and its genitically directed process.
Sporulation process
72
Structure that assists in swimming and helical in shape
Flagella
73
What are the different arrangements of flagellas
1. Petritchous (everywhere)
2. Polar (on side)
3. Iophotrious (many flagella on one side)
74
What is the structure of flagella of bacteria
- consists of several components
- filament composed of different types of protein called flagellin
- move by rotation like a propeller
75
What is the structure of flagella of archea
- half the diameter of bacterial flagella
- composed of several different proteins
- move by rotation
76
True or false:
Flagella increase or decrease rotational speed in relation to strength of the proton motive force
True
77
Arrangement of flagella on cells that move slowly in a straight line
Peritrichously Flagellated Cells
78
Arrangement of flagella on cells that move more rapidly and typically spin around
Polarly flagellated cells
79
Gliding Motility of a Flagella
- independent motility
- slower and smoother than swimming
- movement occurs along long axis of cell
- requires surface contact
80
Mechanisms of Flagella gliding motility
1. Excretion of polysaccharide slime
2. Type IV pili
3. Gliding specific proteins
81
Its the directed movement in response to chemical or physical gradients
Taxis
82
Types of Taxis
1. Chemotaxis
2. Phototaxis
3. Aerotaxis
4. Osmotaxis
5. Hydrotaxis
83
Type of Taxis being described:
- response to chemicals
- best studied in E.coli
- bacteria senses it with chemo receptors to respond to temporal, not spatial, difference in chemical concentration = Run and Tumble behavior
Chemo Taxis
84
Type of Taxis being described:
- response to light
Phototaxis
85
Type of Taxis being described:
- response to oxygen
Aerotaxis
86
Type of Taxis being described:
- response to ionic strength
Osmotictaxis
87
Type of Taxis being described:
- response to water
Hydrotaxis
88
How to measure chemotaxis?
- inserting capillary tube containing an attractant or repellent of motile bacteria
- can also be seen under a microscope
89
They are cells that contain a membrane enclosed nucleus and other organelles
Eukaryotes
90
It contains the DNA of a Cell.
Nucleus
91
Visible under light microscope without staining. Enclosed by two membranes and within it the nucleolus can be found.
Nucleus
92
Wound around histones
DNA
93
Site for ribosomal RNA snythesis
Nucleolus
94
Two types of cell division
Mitosis and Meosis
95
Cell division that is
- normal form of nuclear division in eukaryotic cells
- chromosomes are replicated and partitioned into two nuclei
- results in two diploid daughter cells
Mitosis
96
Cell division that is
- specialized form of nuclear division
- halves the diploid number to the haploid number
- results in four haploid gametes
Meiosis
97
These 3 parts that can be found in cells specialize in energy metabolism
1. Mitochondria
2. Hydrogenosome
3. Chloroplast
98
It creates energy through respiration and oxidative phosphorylation. In bacteria it may be rod or spherical shape. Over 1,000 in animals. Surrounded by two membranes.
Mitochondria
99
Folded internal membranes of mitochondria. Contains enzymes needed for respiration and ATP production
Cristae
100
Innermost area of mitochondrion. Contains enzymes for the oxidation of organic compounds
Matrix
101
Its similar in size to mitochondria but lacks TCA cycle enzymes and cristae. Creates energy through oxidation of pyruvate to H2, CO2, and acetate. Trichomonas and various protists have this
Hydrogenosome
102
Its a chlorophyll containing organelle found in phototropic eukaryotes. its size, shape, and number may vary.
Chloroplast
103
Chloroplast have flattened membrane discs called?
Thylakoids
104
Lumen of chloroplast is called what?
Stroma
105
Stroma contains large amounts of _____________
RubisCO
106
Its a key enzyme for Calvin cycle found in the Stroma
RubisCO
107
It has ribosomes attached to it
Endoplasmic Reticulum
108
Two types of ER
Rough and smooth
109
This type of ER participates in protein synthesis
Smooth ER
110
This type of ER is a major producer of glycoproteins
Rough ER
111
It is stacks of membrane distinct from but functioning in concert with ER. Modifies products of the ER destined for secretion
Golgi Complex
112
They are 25 nm in diameter. composed of a and b tubulin. function in maintaining shape of cell, in motility, in chromosome movement, and movement of organelles
Microtubules
113
They membrane enclosed compartments that contain digestive enzymes used for hydrolysis. It allows for lytic activity to occur within cell without damaging other cellular components
Lysosomes
114
They are 7 nm in diameter, polymers of actin, function in maintaining shape of cell, in motility by pseudopodia, and cell division
Microfilaments
115
They are 8 to 12 nm in diameter; has keratin protein. Function in maintaining cell shape and postioning of organelles in cell
Intermediate Filaments
116
These organelles allow cells to move around by swimming
Flagella and Cilia
