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Flashcards in Exam 1 Deck (141):
1

Staphylo-

Clustered

2

cocci

Spherical 

3

Koch's postulates

  • 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

Treatment with chemical is ______

chemotherapy

5

Chemotherapeutic agents used to treat infectious disease can be _____ drugs or antibiotics

Synthetic 

6

_____ are chemicals produced by bacteria and fungi that inhibit or kill other microbes 

antibiotics 

7

Pleomorphic

multiple shapes

8

monomorphic

one shape

9

Spirillum

one or more twists

 

10

Vibrio

Curved rod

11

Spirochete

Flexible, helical spirals

12

Strepto-

Chains

13

Diplo-

pairs

14

Smaller cells have a _____ suface area/volume ratio

larger

15

An inclusion that provides buoyancy for floating in aquatic enviroments

Gas Vacuole

16

_____ is an absolute requirments for all living organims

Plasma Membrane 

17

Bacterial membranes lack ____ 

sterols (but can contain hopanoids, which are a sterol-like molecule)

18

Homologs of all ___ eukaryotic cytoskeletal elements have been identified in bacteria

19

FtsZ

  • (many bacteria)
  • Forms ring during septum formation in cell division

20

MreB

  • Found in bacilli, not cocci
  • Maintains shape but by positioning peptidoglycan synthesis machinery 

21

CreS

  • rare, maintains curve shape

22

Plasma membrane infolding is observed in

  • many photosynthetic bacteria 
  • many bacteria with high respiratory activity

23

Types of Inclusions

  • Storage 
  • Gas Vacuoles
  • Magnetosomes

24

Magnetosomes

  • 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

28

29

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 

30

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 

58

Monotrichous 

one flagellum

59

Polar flagellum

Flagellum at end of cell

60

Amphitrichous 

one flagellum at each end of cell

61

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 

64

counter clockwise flagellar movement

run

65

clockwise rotation of flagella

tumble 

66

Flagellum is ___ part motor producing torque

2 (rotor and stator) 

67

68

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 

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