Exam 1 Flashcards
(141 cards)
1
Q
Staphylo-
A
Clustered
2
Q
cocci
A
Spherical
3
Q
Koch’s postulates
A
- The same pathogen must be present in every case of the disease
- The pathogen must be isolated from the diseased host and grown in pure culture
- The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal
- The pathogen must be isolated from the inoculated animal and must be shown to be the orginal organism
4
Q
Treatment with chemical is ______
A
chemotherapy
5
Q
Chemotherapeutic agents used to treat infectious disease can be _____ drugs or antibiotics
A
Synthetic
6
Q
_____ are chemicals produced by bacteria and fungi that inhibit or kill other microbes
A
antibiotics
7
Q
Pleomorphic
A
multiple shapes
8
Q
monomorphic
A
one shape
9
Q
Spirillum
A
one or more twists
10
Q
Vibrio
A
Curved rod
11
Q
Spirochete
A
Flexible, helical spirals
12
Q
Strepto-
A
Chains
13
Q
Diplo-
A
pairs
14
Q
Smaller cells have a _____ suface area/volume ratio
A
larger
15
Q
An inclusion that provides buoyancy for floating in aquatic enviroments
A
Gas Vacuole
16
Q
_____ is an absolute requirments for all living organims
A
Plasma Membrane
17
Q
Bacterial membranes lack ____
A
sterols (but can contain hopanoids, which are a sterol-like molecule)
18
Q
Homologs of all ___ eukaryotic cytoskeletal elements have been identified in bacteria
A
3
19
Q
FtsZ
A
- (many bacteria)
- Forms ring during septum formation in cell division
20
Q
MreB
A
- Found in bacilli, not cocci
- Maintains shape but by positioning peptidoglycan synthesis machinery
21
Q
CreS
A
- rare, maintains curve shape
22
Q
Plasma membrane infolding is observed in
A
- many photosynthetic bacteria
- many bacteria with high respiratory activity
23
Q
Types of Inclusions
A
- Storage
- Gas Vacuoles
- Magnetosomes
24
Q
Magnetosomes
A
- found in aquatic bacteria
- magnetitie particles (iron) or orientation in Earth’s magnetic field
- Cytoskeletal protein MamK
- helps form magnetosome chain
25
bactrial and archaea ribosome
70S
26
Eukaryotic ribosome
80S
27
Bacterial ribosome RNA
* 16S small subunit
* 23S and 5S in large subunit
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plasmids
* Extrachromosomal DNA
* found in bacteria, arachaea, and some fungi
* usually small, closed circular DNA molecules
* Exist and replicate independently of chromosome
* episomes- may integrate into chromosome
* inherited during cell division
* Contain few genes that are non-essential
* Confer selective advantage to host (e.g. drug resistance)
* Classification based on mode of existence, spread, and function
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31
Function of conjugative plasmids
* Transfer of DNA from one cell to another
32
R plasmids
* Carry antibiotic-resistance genes
33
functions of Cell wall
* Maintains shape of the bacterium
* Almost all bacteria have one
* Helps protect cell form osmotic lysis
* Helps protect from toxic materials
* May contribute to pathogenicity
34
Chains of peptidoglycan subunits are joined by ____ (covalent bonds) between the peptides
cross-links
35
Meshlike polymer of identical subunits forming long strands
* Two alternating sugars
* N-acetylglucosamine (NAG)
* N-acetylmuramic acid
* Alternating D- and L- amino acids (this is hooked on the NAM)
* ends in D-alanine
36
Fucntions of teichoic acids
* help maintain cell envelope
* protect from environmental substances
* May bind to host cells
37
Periplasmic space of gram positive bacteria
* Lies between plasma membrane and cell wall and is smaller than that of Gram-negative bacteria
* Periplasm has relatively few proteins
* Enzymes secreted by Gram-positive bacterai are called exoenzymes
* aid in degradation of large nutrients
38
What are enzymes secreted by Gram-positive bacteria called
exoenzymes
39
Outer membrane of gram negative cells is composed of
* Lipids
* lipoproteins
* lipopolysaccharide (LPS)
40
\_\_\_\_\_ connect outer membrane to peptidoglycan in gram negative cell wall
Braun's Lipoproteins
41
Lipopolysaccharide (LPS)
* Lipid A (endotoxin)
* Core polysaccharide
* O side chain (O antigen)
42
Lipid A is embedded in the ______ while core polysaccharide O antigen chain \_\_\_\_\_\_
outer membrane, extend out from the cell
43
Importance of LPS
* Contributes to negative charge on cellsurface
* Helps stabilize outer membrane structure
* may contribute to attachment to surfaces and biofilm formation
* Creates a permeability barrier
* Protection from host defenses (O antigen)
* Can act as an endotoxin (lipid A)
44
The outer membrane of gram-negative bacteria is more permable due to
the presence of porin proteins and transporter proteins
45
Lysozyme breaks the bond between ______ and \_\_\_\_\_\_\_
N-acetyl glucosamine and N-acetylmuramic acid
46
Penicillin inhibits \_\_\_\_\_\_
peptidoglycan synthesis
47
What cells that loss a cell wall may survive in Isotonic environments
* Protoplasts
* Spheroplasts
* Mycoplasma
* Does not produce a cell wall
* Plasma membrane more resistance to osmotic pressure
48
Archeal cell walls lack peptidoglycan but some have \_\_\_\_\_\_, also called \_\_\_\_
Pseudopeptidoglycan, pseudomurein
49
Components outside of the cell wall
* Outermost layer in the cell envelope
* glycocalyx
* Capsules and slime layers
* S layers
* Aid in attachment to solid surfaces
* e.g. Biofilms in plant and animals
50
Capsules usually are composed of
* polysaccharides
51
What are the protective advantages of capsules
* resistant to phagocytosis
* protect from desiccation
* exclude viruses and detergents
52
Slime layers
* Similar to capsule except diffuse, unorganized and easily removed
* slime may aid in motility
53
S layers
* Regularly structured layers of protein or glycoprotein that **self-assemble**
* ****in gram-negative bacteria the S layer adheres to outer membrane
* in gram-positive bacteria it is associated with the peptidoglycan surface
54
S layer functions
* Protect from ion and pH fluctuations, osmotic stress, enzymes, and predation
* Maintains shape and rigidity
* Promotes adhesion to surfaces
* Protects from host defenses
* Potential use in nanotechnology
* S layer spontaneoulsy associates
55
functions of flagella
* Motility and swarming behavior
* Attachment to surfaces
* may be virulence factors
56
What are the three components of the flagella
* Filament
* extends from cell surface to the tip
* hollow, rigid cylinder of flagellin protein
* Hook
* links filament to basal body
* Basal Body
* Series of rings that drive flagellar motor
57
Flagellar synthesis
* Complex process involving many genes/gene products
* new flagellin molecules transported through the hollow filament using Type III-like secretion system
* Filament subunits self-assemble with help of filament cap at tip, not base
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Monotrichous
one flagellum
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Polar flagellum
Flagellum at end of cell
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Amphitrichous
one flagellum at each end of cell
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Lophotrichous
Cluster of flagella at one or both ends
62
Peritrichous
spread over entire surface of cell
63
Chemotaxis
move toward chemical attractant such as nutrients, away from harmful substance
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counter clockwise flagellar movement
run
65
clockwise rotation of flagella
tumble
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Flagellum is ___ part motor producing torque
2 (rotor and stator)
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Rotor of flagellum
* C (FliG protein) ring and MS ring turn and interact with stator
69
Stator of flagellum
* Mot A and Mot B proteins
* form channel through plasma membrane
* protons move through Mot A and Mot B channels using energy of proton motive force
* torque powers rotation of the basal body and filament
70
In presence of attractant tumbling frequency is
intermittently reduced and runs in direction fo attractant longer
71
endospores are resistant to what
* heat
* radiation
* chemicals
* desiccation
72
An endospore is a spore surrounded by thin covering called
exosporium
73
What makes an endospore so resistant
* Calcium (coplexed with dipicolinic acid)
* Small, acid-soluble, DNA-bidning proteins (SASPs)
* Dehydrated core
* Spore coat and exosporium protect
* DNA repair enzymes
74
Sporulation usually occurs due to
when growth ceases because of lack of nutrients
75
What are the amino acids in peptidoglycan
* L-alanine
* D-Glutamic acid
* meso-diaminopimelic acid
* D-alanine
76
Direct cross-linking of peptidoglycan is normally observed in
* Gram-negative bacteria
77
Peptide interbridge of peptidoglycan is normally observed in
* Gram positive (this is a chain of 5 glycines from D-ala of one chain to the L-lys of the other chain)
78
Peptidoglycan synthesis uses _____ to transport NAG-NAM-peptapeptide units across the cell membrane
Bactroprenol
79
The cross-linking in peptidoglycan is formed by what type of reaction
Transpeptidation
80
Bactoprenol is a 55-carbon alcohol that attaches to ___ by a pyrophosphate group. and moves peptidoglycan units through hydrophobic membrane
NAM
81
What are the 2 carries involved in peptidoglycan biosynthesis
* Bactoprenol
* Uridine diphosphate
82
Peptidoglycan synthesis
* UDP derivative of NAM and NAG are synthesized
* Sequential addition of amino acids to UDP-NAM to form the NAM-pentapeptide. ATP is used but no tRNA and ribosomes are involved
* NAM-pentapeptide is transferred to bactoprenol phosphate. They are joined by a pyrophosphate bond
* UDP transfers NAG to bactoprenol-NAM-pentapeptide. if glycine bridge is requried then it is formed here (note that the interbridge is formed in the membrane)
* The bactoprenol carrier transports the completed NAG-NAM prentapeptide repeat unit across the membrane
* The NAG-NAM pentapeptide is attached to the growing end of a peptidoglycan chain, increasing the chain's length by one repeat unit
* The bactoprenol carrier moves back across the membrane. As it does, it loses one phosphate, beocming bactoprenol phosphate. It is now ready to begin a new cycle
* Peptide cross-links between peptidoglycan chains are formed by transpeptidation
83
Vancomycin inhibits \_\_\_\_\_\_\_
transpeptidation by binding to D-Ala-D-Ala
84
Cycloserine blocks formaiton of \_\_\_\_
D-Ala-D-Ala
85
Penicillin inhibits the
transpeptidation reaction
86
Bacitracin blocks the
dephosphorylation of bactoprenol pyrophosphate
87
What is the Mordant in gram stain
iodine
88
What is the counterstain in gram staining
safranin
89
Gram-positive cell wall has ___ ring basal body. While a gram-negative cell wall has a ____ ring basal body
2,4
90
Gram-negative cell wall is ___ sensative
tetracycline (because it attacks the ribosome)
91
The basis for acid-fast staining is a ____ cell wall composed of \_\_\_\_\_\_\_
waxy cell wall, mycolic acids
92
Examples of acid fast staining cells
* Mycobacterium
* M. Leprae (Leprosy)
* Tuberculosis
* Nocardia
93
Acid-fast staining methods use \_\_\_\_\_, which is a lipid soluble stain
Carbolfuschsin (contains phenol to help the stain penetrate the cell wall)
94
Cell walls of photsynthetic algae
* Cellulose
* pectin
* silica
95
Cell walls of fungi
* Cellulose
* chitin
* glucan
96
Movement of cytoplasm throughout cells
cytoplasmic streaming
97
The 70S ribosomes are found in ____ and ____ of eukaryotes
chloroplasts and mitochondria
98
Locations of 80S ribosomes in eukaryotes
* Membrane-bound: attached to ER
* Free: in cytoplasm
99
What are lysomsomes
digestive enzymes
100
Functions of Vacuole
Brings food into cells and provdes support
101
Small energy conservation organelles in some anaerobic protists
Hydrogenosomes
102
Flattended, memrbaen delimited sacs in the stroma of chloroplast membrane
Thylakoids
103
Viruses contain
protein and nucleic acid
104
Viroids contain
Only RNA
105
Satellites contain
only nucleic acids
106
Prions contain
proteins only
107
all virions contain a ____ which is composed of nucleic acid (DNA or RNA) and a \_\_\_\_\_\_
nucleocapsid, protein coat (capsid)
108
Capsid of viruses is composed of protein subunits called
capsomeres
109
Carbohydrate-protein complexes on virus envelope
Spikes
110
General characteristics of Viruses
* Obligatory intracellular parasites
* Contain DNA or RNA
* Contain protein coat
* some are enclosed by an envelope
* some viruses have spikes
* most viruses infect only specific types of cells in one host
* Host range is determined by specific host attachment sites and cellular factors
111
Viruses are classified by morphology
* Helical viruses
* Polyhedral viruses
* Enveloped Viruses
* Complex viruses
112
Icosahedron is a regular polyhedron with ____ equilateral faces and ___ vertices
20, 12
113
What are capsomers
ring or know shpaed units made of 5 or 6 protomers
114
functions of spikes or peplomers of the virus envelope
* involved in viral attachement to host cell
* used for identification of virus
* may have enzymatic or other activity
* may play a role in nucleic acid replication
115
Multiplication of animal viruses
* atttachement
* penetration/entry
* uncoating
* biosynthesis
* maturation
* release
116
Three methods used for viral entry
* fusion of the viral envelope with host membrane; nucleocapsid enters
* endocytosis in vesicle; endosome aids in viral uncoating
* injection of nucleic acid
117
Enveloped viruses are released using \_\_\_\_
* Budding
* viral proteins are placed into host membrane
* nucleocapsid may bind to viral proteins
* envelope derived from host cell membrane, but may be golgi, ER, or other
* virus may use actin tails to propel through host membrane
118
Virulent phage
* one reproductive choice
* lyses bacterial host cell
119
Temperate phages
* have two reproductive options
* reproduce lytically as virulent phages do
* remain within host cell without destroying it
120
Lysogenic conversion
* Temperate phage changes phenotype of its host
* bacteria become immune to superinfection
* phage may express pahtogenic toxin or enzyme
* Two advantages to lysogeny for virus
* phage remains viable but may not replicate
* multiplicity of infection ensures survival of host cell
* under appropriate conditions infected bacteria will lyse and release phage particles
* occurs when conditions in the cell cause the prophage to initiate synthesis of new phage particles a process called induction
121
Archeal viruses may be
lystic or temperate
122
Latent and persitent viral infections
* Virus remains in asymptomatic host cell for long periods
* Disease process occurs over longer period; generally is fatal
123
abnormal new cell growth and reproduction due to loss of regulation
neoplasia
124
Reversion to a more primitive or less differentiated state
Anaplasia
125
Spread of cancerous cells throughout body
Metastasis
126
Viruses can cause cancer how
* viral proteins bind host cell tumor suppressor proteins
* carry oncogene into cell and insert it into host genome
* Altered cell regulation
* Insertion of promoter or enhancer next to cellular oncogene
127
Infectious agents composed of closed circular ssRNAs
Viroids
128
Are bacteria and archaea generally haploid (1N)
yes
129
DnaA
initiaiton of replicaiton; binds origin of replicaiton (oriC)
130
DnaB
helicase
131
E. coli has __ DNA polymerases with polymerase ___ playing the major role in replication
5, III
132
DNA polymerase is a haloenzyme
* complex of 10 proteins
* 3 proteins form core enzyme
133
DNA polymerase ___ removes RNA primers, fills gaps with DNA
I
134
\_\_\_\_ forms a phosphodiester bond between 3'-hydroxyl of the gowing stand and the 5' phosphate of an Okazaki fragment
DNA ligase
135
Proofreading of DNA replication is carried out by DNA polymerase \_\_\_, which removes mismatched base form
III, 3' end of growing strand by exonuclease activity of enzyme
136
\_\_\_\_ form when the two circular daughter chromosomes do not separate
Catenanes
137
The shine-dalgarno sequence is on what strand
mRNA
138
The leader sequence is transcribed into mRNA but is not
translated into amino acids
139
The stop codon is immediately followed by
the trailer sequence which contains a terminator sequence used ot stop transcription
140
\_\_\_\_ mRNA is often found in bacteria and archaea
polycistronic
141
RNA po
