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Micro exam 2 Flashcards

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1
Q

peptidoglycan

A

backbone of cell wall in prokaryotes, composed of repeating sugars NAG and NAM

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2
Q

assembly of cell wall

A

NAG and NAM repeat, assembled by enzymes transglycosylae, tarnspeptidase, polymerase, and hydrolase, how cell wall is made can be used for better antibiotics

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3
Q

Cytoplasmic Phase

A

NAG/NAM are built in cytoplasm and are constantly replenished, particularly when dividing

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4
Q

Membrane Associated Phase

A

enzymes link NAG and NAM with lipids to form peptidoglycan

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5
Q

Extracytoplasmic phase

A

new peptidoglycan moves from inside of cell towards outside, incorporating into cell wall

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6
Q

teichoic acid

A

in gram positive bacterial cells in addition to many layers of peptidoglycan (makes the gram positive cell have an overall negative charge)

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7
Q

Gram positive cell walls

A

very thick wall of peptidoglycan covering the plasma membrane with various lipoteichoic acid and wall associated proteins

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8
Q

Gram negative cell walls

A

outer membrane with porins with lipopolysaccharide (O-polysaccharide and lipid A), then a periplasmic space with lipoproteins, a small layer of peptidoglycan and then the plasma membrane

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9
Q

lipopolysaccharide layer

A

outer membrane, composed of lipids, proteins

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10
Q

Porins

A

proteins contain channels that vary in size and specificity and they are responsible for the passage of molecules and ions into and ort of the gram negative cell

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11
Q

translocation protein systems

A

move substances out of the cell

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12
Q

Periplasmic space

A

space between the plasma membrane and the other membrane, filled with gel-like material and contains variety of proteins secreted by the cell

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13
Q

M protien

A

virulence factor in gram positive organisms, protrudes from cell wall, required for infection, antibodies can inhibit it

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14
Q

Mycolic acid

A

in gram positive organisms, synthesizes waxy lipid known as mycolic acid that makes organisms resistant to antibiotics/disinfectants/ect

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15
Q

Lipid A

A

gram negative bacteria, anchors the LPS portion of the outer membrane to phospholipid bilayer, releases endotoxins

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16
Q

O polysaccharides

A

gram negative, carbohydrate chains that are part of the outer membrane located on the side of the membrane that faces the extracellular fluids

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17
Q

structures outside of bacterial cell in adherence

A

glcocalyx, fimbraie, and pili

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18
Q

structures outside of bacterial cell in movement

A

flagella, axial filament, and pilli

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19
Q

Glycocalyx

A

sticky substance on surface of cells made of polysaccharides and polypeptides, many is known as cell layer, and if adhered tightly is known as capsule

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20
Q

slime layer

A

dental decay, permits organisms to adhere to surface and then many organisms adhere to one another, form of glycolyx

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21
Q

The capsule

A

form of glycocalyx, required for infection, inhibits phagocytosis

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22
Q

Fimbriae and Pilli

A

cell wall components involved in adherence, composed of pilin protein, pili also used in transfer of genetic material through conjugation

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23
Q

immune escape

A

ability to evade a host immune response

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24
Q

phase variation

A

number of pilli decreases after initial infection, taking away target for antibodies

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25
Q

antigenic variation (post-translational modification)

A

change or mask the structure of pilli so that antibodies no longer recognize the bacteria invaders

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26
Q

S pilli

A

secreted fragments of pilli that bind to antibody molecules and inactivate them

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27
Q

axial filaments

A

flagellum like structures that wrap around bacterial cell and give it mobility, often referred to as endoflagella

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28
Q

flagella

A

long structure that extends far beyond the cell wall, used for motility and is a classic example of the relationship between structure and function, allow bacteria to move rapidly from one location to another

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29
Q

structure of flagella

A

filament (made of flagellin), hook (links filament to basal body), basal body(rod that has rings strategically fastened to it

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30
Q

Monotrichous

A

the most common form of flagellae, in which the barcterium has one flagellum located at one end of the cell

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31
Q

amphitrichous

A

in which the bacterium has two flagella, one at end of each cell

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32
Q

Lophotrichous

A

in which the bacterium has two or more flagella located at the same end of the cell

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33
Q

Perltrichous

A

another form in which the entire cell is surrounded by flagella

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34
Q

Plasma membrane

A

selective permeability, the membrane is made of hydrophillic (outside heads) and hydrophobic (inner layer) molecules, provides barriers between inside and outside of cell

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35
Q

integral proteins

A

fully penetrate the plasma membrane and in some cases contain a pore that connects the interior of the cell to the extremal environment

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36
Q

Osmosis

A

molecules can move across cell membrae “water chases concentration”

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37
Q

plasmolysis

A

cell loses water and shrivels up, hypotonic

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38
Q

osmotic lysis

A

water enters the cell causing cell to expand and eventually lyse , hypertonic

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39
Q

isotonic environment

A

solute concentrations inside and outside the cell are essentially equal

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40
Q

passive transport

A

simple diffusion and facillitated diffusion

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41
Q

facilitated diffusion

A

molecules are brought across the plasma membrane by carrier molecules (permeases) binding of solute changes shape of protien

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42
Q

active transport

A

the carrying of solute either into or out of a cell against the concentration gradient requires expenditure of ATP and uses specific carrier proteins found in plasma membrane

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43
Q

Efflux pumping

A

proteins are part of “super family of transporters” “revolving door” mechanism in which membrane pumps bring in certain molecules and expel others at the same time

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44
Q

ABC transport system

A

molecule transported forms a complex with binding protien on the outside of the plasma membrane

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45
Q

group translocation

A

unique to bacteria, want to stay in ex) glucose is transformed using phosphotransferase enzyme to glucose-6-phosphate so it can no longer move across cell membrane

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46
Q

secretion

A

involves moving substances from the inside of the cell to the extracellular fluid. secretion involves several plasma membrane proteins that act in a specific sequence

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47
Q

Nuclear region

A

region that is most discernable supercoiled and associated with specific positively charged proteins that stabilize it

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48
Q

inclusion bodies

A

membrane enclosed organelles used to stored materials

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49
Q

metachromatic granules

A

store phosphates in inclusion bodies

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50
Q

physical requirements for bacteria growth

A

temperature, pH, osmotic pressure

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51
Q

psychrophiles

A

bacteria that grow at cold temperatures (0-15 C)

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52
Q

Psychotrophs

A

subset of psychophiles, bacteria that grow best between 20-30C

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53
Q

Mesophiles

A

bacteria that grow best at moderate temperatures, 25-40C, most common types of bacteria and human pathogens

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54
Q

Thermophiles

A

bacteria that grow only at temperatures above 45C, extreme thermophiles if above 80C

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55
Q

minimum growth temperature

A

lowest temperature at which an organism grows

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56
Q

optimal growth temperature

A

the temperature at which the highest rate of growth occurs

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57
Q

acidophiles

A

bacteria that grow at extremely low pH values

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58
Q

osmotic pressure

A

pressure exerted on bacteria by their surroundings, can affect bacterial growth

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59
Q

halophiles

A

bacteria that love being in a high salt environment. Obligate require high salt concentrations, facultative can live with or without it and extreme can grow in the presence of very high salt levels

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60
Q

what are the two ways bacteria obtain carbon?

A

the breakdown of preexisting molecules that contain carbon
atoms, which are then used for construction of new molecules. This
“recycling” process is very common in biological systems, and organisms
that use it are referred to as chemoheterotrophs. (pathogenic bacteria)
CO2 molecules,
and these organisms are referred to as chemoautotrophs.

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61
Q

Nitrogen

A

required for making bacterial amino acids and nucleic acids

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62
Q

Sulfur

A

required for making some bacterial amino acids

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63
Q

Phosphorous

A

required for making bacterial nucleic acids, membrane phospholipid bilayer, and ATP

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64
Q

Potassium, magnesium, calcium

A

required for functioning of certain bacterial enzymes

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65
Q

iron

A

required for bacterial metabolism

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66
Q

aerobes

A

bacteria that require oxygen

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67
Q

faculatative aerobes

A

can grow with or without oxygen

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67
Q

superoxide dimutase

A

convert free radical oxygen into molecular oxygen and peroxide, then uses catalase to convert hydrogen peroxide to water and oxygen

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68
Q

catalase

A

converts hydrogen peroxide to water and oxygen

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69
Q

aerotolerant bacteria

A

can grow in the presence of oxygen but do not use it in metabolism

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69
Q

peroxidase

A

convert hydrogen peroxide to water

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69
Q

microaerophiles

A

aerobic bacteria but require only low levels of oxygen for growth

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70
Q

Sodium thioglycolate

A

This medium forms an oxygen
gradient such that the farther into the medium we go, the less oxygen
there is. When bacteria with different oxygen requirements are compared
using this medium (Figure 10.6), obligate anaerobes will always grow in
the area of the tube where oxygen is absent, whereas obligate aerobes
grow only where the oxygen concentration is highest. Facultative anaerobes,
which can grow either with or without oxygen, grow throughout
the sodium thioglycolate medium even though the oxygen concentration
decreases steadily from top to bottom of the tube.

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71
Q

GasPak Jar

A

incubation jar totally devoid of oxygen, only obligate and facultative anaerobes can grow in it

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72
Q

fastidious bacterium

A

slow growing, require a large number of growth factors

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73
Q

chemically defined growth medium

A

chemical composition is precisely known

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74
Q

Complex media

A

complex media contain not
only numerous ingredients of known chemical composition but also
digested proteins and extracts derived from plants or meat. Such media
are referred to as complex because the exact chemical composition of
these digests and extracts is not known.

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75
Q

nutrient broth vs solid

A

both complex media, broth in liquid form, solid is media with agar added

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76
Q

selective media

A

one that contains ingrediants that prohibit the growth of some organisms while fostering the growth of others

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77
Q

differential medium

A

contains ingredients that can differentiate between organisms

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78
Q

MacConkey medium

A

culture and differentiation of bacteria based on their ability to ferment lactose, lactose fermenters form red to pink colonies, non fermenters form colorless or transparent colonies

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79
Q

Eosin methylene blue (EMB) agar

A

isolation, culture, and differentiation of gram-negative bacteria. Lactose fermenting bacteria form green metallic sheen, non fermenting bacteria form colorless or light purple colonies

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80
Q

Triple sugar Iron agar

A

Differentiation of
Gram-negative
bacteria on the basis
of their fermentation
of glucose, sucrose,
and lactose and on
their production of
H2S gas
Red slant/red butt, no
fermentation; yellow slant/
red butt, glucose fermentation;
yellow slant/yellow butt, glucose
and lactose fermentation; butt
turns black, H2S produced

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81
Q

Blood agar

A

Culture of fastidious
bacteria and
differentiation of
hemolytic bacteria
Partial digestion of blood, alpha
hemolysis; complete digestion
of blood, beta hemolysis; no
digestion of blood, gamma
hemolysis

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82
Q

Mannitol Salt agar (MSA)

A

selective/differential medium that is useful for identifying Gram-positive organisms. Uses high salt concentration to select for Staphylococcus species while inhibiting
the growth of other bacteria. In addition to this selection, the mannitol
sugar in MSA permits differentiation between species of Staphylococcus.

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83
Q

Generation time

A

time interval between divisions of bacteria (bacteria divide using binary fission)

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84
Q

lag phase

A

stage of bacterial growth the bacteria are adjusting to their environment
and may have to synthesize enzymes to utilize the nutrients available
in the environment. In this phase, little if any binary fission occurs, indicated
by the fact that the growth curve is horizontal

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85
Q

Log phase

A

the number of bacteria doubles and increases exponentially and will have reached the constant
minimum generation time. This level of growth can be sustained only
while environmental conditions remain favorable and, more importantly,
only if an adequate supply of nutrients remains available

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86
Q

Stationary phase of ggrowth

A

the phase in which
the number of cells dying is essentially equal to the number being produced
through cell division. This phase is relatively short because it is
predicated on the availability of nutrients, which continue to disappear
as the growth curve shifts to the last phase.

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87
Q

death phase

A

represents
a continuous decline in the number of dividing cells. This decline
is caused by exhaustion of the nutrient supply as well as collapse of the
environment due to the build-up of toxic waste materials

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88
Q

DNA structure

A

deoxyribonucleic acid, double stranded helical model made of nucleotides (phosphate and sugar with deoxyribose backbone), antiparallel (3’->5’ and reverse)

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89
Q

purines

A

adenine and guanin, large double ring structures

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90
Q

pyrimidines

A

thymine and cytosine, single ring structures

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91
Q

DNA pairings

A

adenine with thymine and cytosine with guanine (AT Genetics Class)

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92
Q

structure of RNA

A

RNA contains the sugar ribose rather than deoxyribose.
* The bases in RNA are adenine, cytosine, guanine, and uracil, and
the base pairings are adenine with uracil, cytosine with guanine.
* RNA is usually found in a single-stranded form. However, RNA can
fold on itself and form areas that are in a double-stranded form (see
the discussion below).

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93
Q

messenger RNA

A

containing information derived from DNA that is used for construction of proteins

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94
Q

Transfer RNA

A

carries amino acids to the ribosome where protein is being constructed

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95
Q

ribosomal rna rRNA

A

helps in maintaining the proper shape of the ribosome and the orientation of the protein under construction

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96
Q

Supercoiling

A

helix twists around itself, before strands can be unwound and separated for replication and transcription, topoisomerase does unwinding

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97
Q

helicase

A

once enzyme is relaxed from supercoiling by topoisomerase, helicase unwinds and separates the chains

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98
Q

Primer:template junction

A

Once the double-stranded DNA has
been unwound, each unwound single DNA strand is called a template.
A portion of this template is then paired with a short segment of RNA
called a primer.
gives the DNA polymerase a place to which the next base can be attached

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99
Q

DNA polymerase

A

enzyme, uses primer:junction as a guide and then takes any of the bases and binds them, can bind many bases at onetime, proofreads

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100
Q

exonuclease

A

enzymes that attack the open ends of molecules, proofread on growing end of 3’, strongly attracted to bases that are improperly added and degrades them

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101
Q

replication fork

A

where in DNA double helix replication is occuring, and the double helix is being unwound and the strands are being separated from eachother,

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102
Q

leading strand

A

the 3’ DNA strand which has an addition onto it’s 3’ end polymerase can add bases and moves towards the fork

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103
Q

lagging strand

A

the 5’ DNA strand which is moving away from the fork, necessitates replicating the lagging strand in pieces AKA Okazaki fragments

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104
Q

primase

A

can synthesize RNA without a 3’ end being present (this synthesis can occur at any place along the DNA sequence). As the replication fork moves, the lagging strand of DNA elongates, and a primase molecule attaches to the strand and synthesizes a small piece of
RNA. This RNA becomes the primer part of the primer:template junction.

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104
Q

DNA ligase

A

the ends of DNA pieces are linked together after RNAaseH removes primer

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104
Q

RNAaseH

A

enzyme that removes the primer RNA the dap that results from the missing primer is filled by DNA polymerase

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2
3
4
5
Perfectly
105
Q

origin of replication

A

location of Initiation of DNA replication in bacteria begins at a specific spot on the
chromosome

106
Q

replicator sequence

A

a specific set of DNA sequences that includes a long
string of A-T base pairs. easily opened because less H bonds

107
Q

Degenerate

A

only 20 amino acids are used to make all the proteins found in all organisms, minimizes the effect of mutations

108
Q

wobble hypothesis

A

francis crick, states that point mutations are less likely to cause harm due to degenerate feature of codons

109
Q

Stop codons

A

end of the construction of a protein, UAA, UAG, UGA

110
Q

reading frame

A

place between initiation/start codon and the end codon, determines how proteins are constructed

111
Q

transcription

A

construction of RNA from a DNA template

112
Q

translation

A

construction of protein by using RNA instruction

113
Q

differences between RNA transcriptction and DNA replication

A
  • RNA synthesis does not require a primer:template junction.
  • RNA does not remain base-paired to the DNA template once transcription
    is complete.
  • Unlike DNA polymerase, RNA polymerase is a poor proofreader.
    This makes RNA synthesis less accurate than DNA replication.
  • Transcription copies only certain portions of a DNA strand, whereas
    replication copies all of it.
114
Q

process of transcription

A

initiation (promoter binds to polymerase)
elongation (RNA polymerase unwinds DNA, adds bases to the growing end of the RNA and closes the DNA strand)
Termination (when the
polymerase reaches a segment of the DNA that signals the end of the
required RNA segment it detaches from the DNA)

115
Q

What types of DNA are used in translation?

A

all three types: mRNA, tRNA, rRNA

116
Q

messenger RNA in translation

A

proton coding region of mRNA includes and open reading frame (ORF) which has a start and top codon, mRNA binds to frame and then recruit a ribosome through complimentary base pairing.

117
Q

transfer RNA in translation

A

tRNA functions as adapters between mRNA attached to a ribosome and the amino acids being added to the growing protein chain, each tRNA attaches to an amino acid and a specific codon, cloverleaf structure

118
Q

anticodon loop

A

part of tRNA clover structure, is the loop farthest from the arm and is where codon recognition occurs. The whole region of the cloverleaf is the anticodon region

119
Q

aminoacyl-tRNA synthetases

A

amino acid specific (20 different enzymes)
aids in the attaching an amino acid to tRNA is a two-step process. Step one is
coupling of the amino acid to AMP. The second step is transfer of the
amino acid to the 3’ end of the tRNA, low error rate

120
Q

large subunit ribosome

A

responsible for peptide bond formation

121
Q

small subunit ribosome

A

contains the decoding center where tRNA bonds to the mRNA (where codon-anticodon recognition occurs)

122
Q

polyribosome

A

during translation more than one ribosome can attach to the same mRNA molecule

123
Q

peptidyl transferase reaction

A

the reaction that bonds each amino acid being added to the growing peptide chain in translation

124
Q

3 binding sites for tRNA

A

a site is for tRNA carrying a single amino acid, P site is for peptidyl-tRNA, which is holding on to the growing peptide chain, and the
E site is for tRNA that is in the process of exiting from the ribosome.

125
Q

3 stages of translation

A

initiation, elongation, termination

126
Q

translation initiation

A

1) recruitment of the
ribosome to the mRNA to form what is referred to as the translational
apparatus, (2) placement of a methionine tRNA and its amino acid on the
P site (note that this first tRNA does not go to the A site first), (3) precise
positioning of the ribosome over the mRNA start codon (establishes open reading frame)

127
Q

translation elongation

A

aminoacyl-tRNA binds to A site, peptide bond formation, translocation, proofreading between mRNA and tRNA

128
Q

translation termination

A

translation continues until a stop codon enters the A site, then peptide chain released from ribosome and subunits of ribosomes disassociate from mRNA

129
Q

constitutive gene

A

a gene that is always on/expressed , regulated by positive regulation (proteins boost production) or negative regulation (proteins repress production)

130
Q

operator site

A

region of DNA strand where the regulatory proteins bind

131
Q

lac operon

A

lactose operon, positive regulation, set of genes that enable bacteria to use sugar lactose, inducible genes (off but can be turned on), turned on using lac activator CAP, repression is always on but lac operon activates if environment does not contain glucose

132
Q

tryptophan production

A

feeback inhibition that occurs post transcription, tryptophan is made until it accumulates in excess and then opresses it’s own synthesis by the excess bying to a repressor protein which changes the chape of the geses and prevents further synthesis

133
Q

silent mutation

A

point mutation, single base change in DNA with no change in ammino acid, causes no effect in the protein

134
Q

missense mutation

A

point mutation, change in DNA sequence that results in a change in the amino acid sequence, causes a change in the protein that can cause significant alteration of protein function

135
Q

nonsense mutation

A

change in DNA sequence that creates a premature stop codon, produces truncated and non-functional protein

136
Q

frame shift mutation

A

deletion or insertion of one or more bases into the DNA sequence, changes the entire sequence of codons and greatly alters the amino acid sequence. transposition is a form of insertion that can cause a frameshift and change the genetic makeup of bacterium

137
Q

transposons

A

jumping DNA, generates much of the frameshift mutations

138
Q

suppressor mutations

A

reverse the primary mutation and reestablish the construction of a functional protein

139
Q

mutagens

A

chemicals that cause DNA mutation
ex) radiation

140
Q

nucleotide excision

A

looks for distortion of DNA double helix and removes strands of DNA near the mutation and allows DNA polymerase and ligase to fix

141
Q

base excision

A

enzyme specific, enzyme flips out base and corrects it

142
Q

photoreactivation

A

unlinks the damaging thymine dimers formed when DNA is exposed to UV radiation, uses photolyase

143
Q

recombination

A

bacteria “shuffle” their genes using transformation, transduction, conjugation, and transposition

144
Q

transposition

A

genetic elements
called transposons move from one place on a bacterial chromosome to
another, random so can be good or bad, most common form of mutation

145
Q

transformation

A

naked DNA released after cell death is taken up y a bacteria cell and recombines with that cell’s DNA

146
Q

griffith experiment

A

shows transformation
a) living bacteria into mice and mouse dies
b) living nonencapsulated bacteria into mouse and mouse lives
c) heat killed encapsulated bacteria into mouse and mouse lives, living nonencapsulated and heat-killed encapsulated bacteria injected into mouse and mouse dies
**concludes that the bacteria had transformed to gain genes for a capsule

147
Q

generalized transduction

A

DNase cleaves DNA and is randomly carried into viral particles, recombines with newly infected host cell DNA in the recipients chromosome

148
Q

specialized transduction

A

the phage DNA initially becomes incorporated
into an infected cell’s chromosome and is called a prophage, excise from chromosome and join acterial chromosome “donor DNA”

149
Q

conjugation

A

direct contact between donor and recipient cells, plasmid DNA travels through pilus between DNA

150
Q

HFR

A

In an Hfr cell, the host chromosome has a prophage integrated into it. When this cell is
involved in conjugation it can transfer host cell DNA sequences that are adjacent to the
integrated prophage

151
Q

dissimilation plasmids

A

contain genetic information that allows organisms to become more resistant to disinfectants and more able to adapt to otherwise destructive environments

152
Q

obligate intercellular parasites

A

viruses, cannot live outside of a cellular host (multiply and produce new viral particles)

153
Q

capsid

A

protein coat that encloses the genetic material of viruses, may also wrap in envelope of lipids or host membranes

154
Q

virion

A

a single viral particle
must hold up to environment and be able to shed capsid once entering host cell

155
Q

capsomere

A

protein subunits forming capsid

156
Q

capsid

A

protein coat, protein shell surrounding nucleic acid

157
Q

nucleocapsid

A

nucleic acid plus capsid

158
Q

envelope

A

viral membrane, phospholipid bilayer with embedded glycoproteins surrounding capsid in enveloped virus

159
Q

viron

A

viral particle, complete infectious viral structure: nucleic acid plus capsid for non-enveloped virus, nucleic acid plus capsid plus envelope for enveloped virus

160
Q

helical viruses

A

bonding of capsomeres determine symmetry, helical have a rod shape or a filamentous/curve shape, segmented RNA ex)influenza

161
Q

nucleoproteins

A

in helical viruses each segment of RNA is enclosed in a helical capsid held in place by multiple proteins called nucleoproteins

162
Q

matrix protein

A

within helical viruses, second layer of protein just inside the envelope

163
Q

Icosahedral

A

type of shape of DNA, based on 20 triangle faces of capsid, has 12 points, ex) polio (simple)

164
Q

simple icosahedral virus

A

the capsid is made of a large number of identical 3-polypeptide capsomeres ex) polio

165
Q

complex icosahedra viruses

A

icosahedral virus with additional proteins and lipids surrounding the capsid ex) herpes

166
Q

tegument

A

protein layer located between capsid and envelope in icosahedral viruses

167
Q

complex viruses

A

viruses that do not have either helical or icosahedral symmetry ex) pox virus

168
Q

genomic packing

A

There are three ways in which viruses package their nucleic acid: (1) directly in the capsid (simplest, attachment occurs at inner side of protein coat) (2) enclosed in specialized proteins (nucleic acid-binding proteins, very stable) (3) enclosed in proteins from the host cell

169
Q

bacteriophages

A

viruses that infect bacteria, helps provide information on infection cycle

170
Q

lytic infection cycle

A

seen in animal virus, During the infection cycle of many viruses, the host cell is used to produce more virions, and when the host cell is completely filled with new
virions the host cell simply bursts. This is called lysis

171
Q

lysogenic cycle

A

viral genome becomes incorporated into the host
cell’s DNA and can remain this way for an extended period, causes latent infection

172
Q

latent infection

A

no new virus made and no increase in infection, when to leave latency and become lytic is based on health of host cell

173
Q

steps of lytic infection

A

attachment (virion binds to specific receptors on host cell), penetration (may conformationally change capsomere), uncoating (simple uncoating at plasma membrane or uncoating within endosomes or uncoating at nuclear membrane), biosynthesis (synthesis of new viral components as well as new viral genomes), maturation(movement of newly made viral components to specific sites in the host cell and assembly of new virions), and release (lysis or budding off from the host cell)

174
Q

lipid rafts

A

specific areas of host membrane, rich in cholesterol, fatty acids, and lipids, which make them more densely packed for stable attachment

175
Q

endosome

A

membrane encloses virion to form a vesicle, acidic environment that helps begin uncoating of virion, then fuses with lysosomes to complete uncoating

176
Q

compartmentalization

A

In this process, DNA or RNA synthesis of viral genomes as well as synthesis of the new capsids and other viral proteins occurs in specific locations of the host cell. After synthesis, these components are finally moved to other specialized sites for final assembly of the intact virions.

177
Q

reverse transcriptase

A

can convert RNA into DNA, must penetrate the double membrane for infection to occur, uses import pathways

178
Q

double-stranded DNA (dsDNA) viruses

A

mRNA required to make viral proteins can be produced by transcribing one stand of the viral DNA, uses either host or viral RNA polymerase molecules for RNA synthesis

179
Q

Single-stranded DNA (ssDNA) viruses

A

DRN strand must be transcribed to RNA but mRNA cannot be transcribed from single-stranded DNA so 1st strand is used to make second strand which is then used as a template for new viral genomes

180
Q

DNA replication in latent viruses

A

latent virus incorporates it’s genome with host chromosomes, does not need maximal production of viral genomes, only a small number of viral gens replicate at a different location than in lytic

181
Q

viral transcription

A

newly made viral DNA molecule acts as a template for the creation of viral mRNA, preformed by host’s RNA polymerase, in dsDNA viruses transcription begins as soon as it reaches host nucleus, in ssDNA viruses the single DNA strands must first be converted to double to serve as transcription templates, very high rate of transcription but also high regulation

182
Q

double stranded RNA viruses

A

Double-stranded RNA virus
genomes contain both a (+) and a (–) strand. During infection, the (–) strand
is first copied into mRNA by a viral RNA polymerase to produce viral proteins.
This newly synthesized strand is then used as a template to make a doublestranded
genome, which will be placed into new virions

183
Q

+ single stranded RNA viruses

A

the (+) strand
is essentially already mRNA and as such it can be directly translated into
viral proteins by the host cell’s ribosomes. Genome replication takes two
steps. First the (+) strand is copied into a (–) strand. Then this (–) strand
is used as a template to produce more (+) strand genomes to place into
new virions

184
Q
  • single stranded RNA virus
A

(–) strand cannot be
directly used as mRNA. Therefore, it must first be copied into a (+) strand
by viral RNA polymerase, which is brought in with the virus. This (+) strand
copy is mRNA and can be used for the synthesis of viral proteins. The production
of genomes for new virions goes through a two-step sequence
in which the (–) strand is copied to a (+) strand and this (+) strand is then
used as the template for new (–) strand genomes that are packaged into
new virions

185
Q

intracellular trafficking

A

movement of newly made viral components to specific sites in the host cell, done through a series of membrane-enclosed compartments and vesicles using ER and golgi apparatus

186
Q

assembly of non-enveloped viruses

A
  • Formation of structural subunits for the capsid
  • Assembly of the capsid
  • Association of viral genome within the capsid
187
Q

assembly of enveloped virus

A
  • Formation of structural subunits for the capsid
  • Assembly of the capsid
  • Association of viral genome within the capsid
  • Assembly of viral envelope glycoproteins
188
Q

concerted assembly

A

the virion is assembled while the viral genome is being synthesized

189
Q

sequential assembly

A

the viral genome is inserted into already-formed capsids. This latter type of assembly requires a mechanism in which the genome can be pushed or pulled into the capsid. It also requires a portal of entry into the capsid. higher rate of error

190
Q

budding from plasma membrane

A

bud formation, bud growth, fusion of the bud
membrane, and separation from the host.

191
Q

synctia

A

a possible way viruses spread, multinucleate mases formed by fusion of many infected cells

192
Q

acute vs persistent viral infections

A

acute: rapid and self-limiting
persistent: long term ex)latent, or slow/transforming infections

193
Q

cytopathic virus

A

kill their host cells rapidly to yield the maximum number of virions for continuation of the infections

194
Q

non-cytopathic viruses

A

produce virions but do not kill host cells

195
Q

antigenic variation

A

Changes in virion structure. host can be reinfected because they use amino acid substitutions to change the protein configuration to a form that the adaptive response has not “seen” and therefore cannot respond to

196
Q

antigenic drift

A

slight change in the virion structure, resulting from mutations, occurs after the infection has begun

197
Q

antigenic shift

A

major changes in the structure of the virion as a result of the acquisition of new genes either from co-infection or through recombination events

198
Q

characters of latent infections

A
  • Absence of a productive infection, in other words, no large-scale production of virions
  • Reduced or absent host immune response
  • Persistence of an intact viral genome so that productive infections can occur later
    ex)shingles and herpes warts
199
Q

susceptibility

A

the host cell must have the appropriate receptor for viral attachmentp

200
Q

permissiveness

A

the host cell contains gene products used y the virus for a successful infection

201
Q

site of entry

A

where the virus enters the body
respiratory tract (most common), digestive tract (common but hostile due to stomach, infected by durable and resistant viruses), urogenital tract (STDs, low defense, often lifelong), eyes (little rate of infection due to constant flushing of eye), skin (barrier must be broken, often insect carried)

202
Q

locations for dissemination of viruses

A

nervous system (infect through neurons, get to brain and spinal cord), organs such as liver spleen and bone marrow (reaches blood and then makes into vessels and tissues)

203
Q

hematogenous dissemination

A

virus using bloodstream as best route for dissemination

204
Q

active viremia

A

virions replicate in the blood

205
Q

zoonotic diseases

A

diseases that have perpetuation of the infection by transmission from other animals to humans

206
Q

iatrogenic transmission

A

viral transmission facilitated by poor techniques employed by healthcare workers

207
Q

transmission via epidermis

A

skin rashes
macular lesions (red spots on skin)
papules (small solid elevated lesions)

208
Q

virulence

A

capacity of an infectious organism to cause disease

209
Q

attenuated visuses

A

non virulent, do not cause disease

210
Q

PD50

A

paralytic dose 50%, indicates how much virus is needed to paralyze 50% of infected individuals

211
Q

susceptible vs immune hosts

A

susceptible hosts can be infected and transmit the disease
immune hosts can’t be infected or will not transmit the disease
making more a population immune through either infection or vaccination creates herd immunity

212
Q

live attenuated vaccine

A

made up of intact viral particles and have been rendered non-infectious through some form of chemical treatment
ex) pollio drop, measles mumps and rubella (MMR)

213
Q

inactivated vaccine

A

aka killed vaccine, composed of a virus that is either dead or non-infectious, safer than live attenuated

214
Q

subunit vaccine

A

composed of immunogenic parts of the virus and is usually derived through the use of genetic engineering and recumbent DNA techniques, safest type, ex) covid vaccines

215
Q

active immunization

A

antigen representing the infectious agent is administered and causes the onset of an immune response

216
Q

passive immunization

A

already-formed anti-viral product such as antibody

217
Q

two groups of parasites

A

protozoans (microscopic single-celled eukaryotes)
helminths (multicellular worms with differentiated tissues and complex organ systems)

218
Q

how are parasitic protozoans classified?

A

by their method of locomotion, bodies are broken into endoplasm (nutrition and metabolism) and ectoplasm (movement)

219
Q

Rhizopods

A

amoebas, most simple, free living protozoans, form commensal relationships in the human intestine

220
Q

Cilliates

A

move through the use of cilia and are rarely parasitic
flagellates are parasitic organisms

221
Q

Sporozoa

A

cause malaria, asexual and sexual reproduction during infection cycle

222
Q

schizogony

A

cycle of simple fission in reproduction of parasites, followed by a sexual reproduction phase called gametogony

223
Q

general characteristics of a helminth

A

worms
bilaterally symmetrical
covered in acellular cuticle as outer layer
differentiated organs including nervous, excretory, and reproductive
no circulatory system

224
Q

Nematodes

A

Roundworms
cylindrical body and alimentary canal from mouth and anus, separate sexes, 2 types: GI tract nematodes and blood/tissue nematodes

225
Q

cestode

A

tapeworm
head with segmented body (proglottids), hermaphroditic, no alimentary (digestive) tract, typically one host per fife cycle

226
Q

trematodes

A

flukes
leaf-shaped with oral and ventral suckers, hermaphroditic, blind pocket digestive, two intermediate hosts

227
Q

definitive host

A

parasitic host in which asexual reproduction occurs

228
Q

intermediate host

A

parasitic host in which sexual development occurs

229
Q

malaria

A

plasmodium species of sporozoan, parasitic infection of human red blood cells

230
Q

life cycle of plasmodium (sexual)

A

mosquito ingests plasmodium gametocytes from blood, when fertilized forms oocyst, which inside has thousands or sporozoites and then the cyst ruptures the sporozoites fill mosquito body

231
Q

life cycle of plasmodium (asexual)

A

sporozoites transferred from mosquito when biting human, find way to liver and attach to hepatocyte, asexually reproduce and from daughter cells called merozoites, these rupture releasing merozoites and enter ring stage where merozoits attach to specific receptors on red blood cells

232
Q

pathognesis of malaria

A

fever, anemia (malaria destroys red blood cells), circulatory changes (hypotension), incubation to onset is 2 weeks

233
Q

malarial paroxysm

A

cycle of the malaria disease, cold and hot stages

234
Q

life cycle of toxoplasma

A

begins in intestine of cat, trophozoite for of parasite enters cells and becomes merozoites, causes epithelial cells to rupture and release parasite into fecal matter for 2-3 weeks, enter macrophages in hosts blood and travel to all organs which can lead to death of host cells

235
Q

amebiasis

A

diseases caused by rhizopods, found in trophozite form or cyst form, dwell in colon and cause diahrehha, infection caused by fecal oral route where cyst passes through stomach degrades in small intestine and releases trophozoites which repeat the process

236
Q

flagellates diseases

A

trichiniasis (STD, vaginitis, has axostyle microtubule to attach to host), trypanosomiasis (infects fly which infect humans and can cause sleeping sickness or Chaga’s disease, reproduces by longitudinal binary fission, localizes in heart and CNS)

237
Q

diseases caused by intestinal nematodes

A

enterobiasis, ascariasis, hookworm infections
severity of disease depends on the level of adaptation to the host

238
Q

enterobiasis

A

nematode, pinworm, temperate regions of europe and north america, transmitted in gatherings of children, pinworms attach to cecum of large intestine and eggs leave the anus which are then transferred through the fecal-oral route

239
Q

Ascariasis

A

nematode, roundworm, picked up from eggs in soil, parasite lives in small intestine, larvae enter the liver, travel through hepatic vein into lungs where they are coughed up and swallowed, regaining access to the intestine

240
Q

microfilariae

A

live offspring of nematodes

241
Q

trichinosis

A

nematode, lives in duodenal of swine and bears, enter vascular system and penetrate tissues, if a carnivore eats swine diseases is transferred

242
Q

cestodes

A

tapeworms, largest intestinal parasite, lack vascular respiratory and digestive systems, body has a head (scolex) a regenerative neck and a long segmented body, severity of tapeworm infection depends on if patient is primary or intermediate host

243
Q

trematodes

A

flukes, can be hermaphrodites or schistosomes,

244
Q

miracidia

A

if eggs from nematode reach water they hatch and lay these ciliated larvae, reach snails and reproduce into tail-bearing larvae called cercariae, this is finish is schistosome but if hermaphrodite the cercariae enter a plant and animal and develop into metacercariae which then can infect humans

245
Q

types of flukes

A

lung fluke, liver fluke, and blood flukes

246
Q

mycology

A

study of fungi, unicellular (yeasts) and multicellular (molds)

247
Q

how is the plasma membrane of fungi different from bacteria?

A

fungal cells have sterol erogsterol and are surrounded by a cell wall made of the polysaccharides mannan glucan and chitin

248
Q

conida

A

asexual reproductive elements of fungi, involves mitotic division

249
Q

blastoconida

A

budding of yeast, new cell projects from an existing cell

250
Q

hyphae

A

seen in molds, tubelike extensions of the cytoplasm, intertwine to form mycelium which then cross to for septa (cross walls)

251
Q

dimorphism

A

some fungi can grow in either a yeast or mold form depending on the environment (temperature and nutrients)

252
Q

mycosis

A

any disease caused by a fungus, superficial mycosis does not involve tissue response

253
Q

piedra

A

colonization of the hair shaft characterized by nodules attached to the hair

254
Q

tinea nigra

A

fungal superficial skin lesions
ex) tinea corpis is ringworm

255
Q

pityriasis

A

dermatitis caused by itching of the skin, yeast, folliculitis

256
Q

tinea capitis

A

scalp and eyebrows fungal infection

257
Q

favus

A

hair loss due to permanent destruction of hair follicle

258
Q

different ringworm classifications

A

tineas pedis (athletes foot), tinea corporis (fingers/palm), tinea cruris (genitals)

259
Q

onychomycosis

A

nailbed and nail infection

260
Q

mucocutaneous candidiasis

A

caused by candida albicans, thrush or vulvovaginitis, yeast infection

261
Q

hyperkeratosis

A

scaly areas on hands and feet

262
Q

keratitis

A

colonization of corneal epithelium (eyes), caused by careless contact applications

263
Q

sporotrichosis

A

subcutaneous mycoses, occur after traumatic implantation of fungal organism

264
Q

paranasal conidoblomycoses

A

infection of paranasal sinuses that form granulated fibrotic tissue

265
Q

zygomatic rinitus

A

mucosa become grayis, invades tissue through the arteries causing blood clots

266
Q

types of deep mycoses

A

localized or systematic, often seen in immunocompromised patients
systematic: localized to deep tissues and organs
disseminated mycosis: moves from the initial site from blood or lymph

267
Q

pathogenesis of fungal infections

A

adherence: adhere to the mucosal surface of GI or female genital tract
invasion: introduced to tissues through mechanical breaks in the skin
tissue injury: host inflammatory and immune response

268
Q

phagocytosis

A

neutrophils kill any fungal hyphae that reach tissues

269
Q
A

Microbiology (6 decks)

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