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micropara > LEC 4 ACELL/PROKAR MICROBES > Flashcards

LEC 4 ACELL/PROKAR MICROBES Flashcards

1
Q

complete viruses are called

A

virions

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2
Q

most viruses range from ______ in diameter

A

10 to 300 NM

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3
Q

some viruses, called ________ cause specific types of cancers

A

oncogenic viruses or oncoviruses

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4
Q

surrounded by _____ which is composed of protein units called CAPSOMERES

A

capsid (protein coat)

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5
Q

have an outer _______. hence the name envelope

A

envelope (lipids and polysaccharides)

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6
Q

viruses originated in the primordial soup and coevolved with bacteria and archaea

A

COEVOLUTION THEORY

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7
Q

viruses evolved from FREE LIVIMG PROKARYOTES that invaded other living organisms, and gradually lost functions which were provided by the host cell

A

retrograde evolution theory

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8
Q

viruses are pieces of host cell RNA or DNA that have escaped from living cells and are no longer under cellular control. of the three theories, this is currently the most widely acellular explanation for the origin of viruses

A

escaped gene theory

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9
Q

Viruses have FIVE PROPERTIES that distinguish them from living cells:

A
  1. They possess either DNA or RNA.
  2. They are unable to replicate on their own.
  3. Unlike cells, they do not divide by binary fission, mitosis, or meiosis.
  4. They lack the genes and enzymes necessary for energy production.
  5. They depend on the ribosomes, enzymes, and metabolites of the host cell for
    protein and nucleic acid production
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10
Q

most VIRAL GENOMES ARE THE FIRST two types

A

double stranded DNA VIRUSES and single stranded RNA viruses

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11
Q

most viral genomes are CIRCULAR molecules, but some are

A

LINEAR

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12
Q

viruses that infect bacteria are known as _________ or simply PHAGES

A

bacteriophages

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13
Q

who is the 2 people who create G. phagein “TO DEVOUR”?

A

frederick twort and felix d’herelle

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14
Q

2 types of bacteriophages

A

VIRULENT AND TEMPERATE

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15
Q

virulent bacteriophages always causes what is known as the ____ cycle.

A

lytic

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16
Q

3 categories of bacteriophages based on their SHAPE

A
  1. Icosahedron
  2. filamentous
  3. complex
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17
Q

the five steps in the lytic cycle

A
  1. attachment
  2. penetration
  3. biosynthesis
  4. assemnly
  5. release
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18
Q

______ escape from their host cells either by lysis of the cell or by budding. viruses that escaped by budding become enveloped viruses

A

animal viruses

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19
Q

viral infections in which the virus is able to hide from the host’s immune system by entering cells and remaining dormant

(ex: herpes viral infections)

A

latent virus infections

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20
Q

chickenpox may be followed, years later, by _____ — both the result of the same birus because those chickenpox/____ never completely go away

A

shingles

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21
Q
  • what is not effective against viral infections — this is very important to remembers.
A

antibiotics

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22
Q

are drugs that are used to treat viral infections .These agents interfere with virus-specific enzymes and virus production by disrupting critical phases in viral multiplication or inhibiting synthesis of viral DNA, RNA, or proteins

A

ANTIVIRAL AGENTS

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23
Q

• These viruses cause cancer.
• Examples include Epstein–Barr virus,
human papillomaviruses, and human T-
lymphotrophic virus type 1 (HTLV-1)

A

oncogenic viruses or oncoviruses

24
Q

• This virus causes acquired
immunodeficiency syndrome (AIDS).
• It is an enveloped, single-stranded RNA
virus.
• The primary targets for HIV are CD4+ cells

A

UNODEFICIENCY VIRUS (HIV)

25
Q

viroids and priors are

A

SMALLER AND LESS COMPLEX INFECTIOUS PARTICLES THAN VIRUSES

26
Q

___ are short, naked fragments of single-stranded RNA, which can interfere with the metabolism of PLANT CELLS
- are transmitted between plants in the same manner as viruses
- ex are potato spindle tuber and citrus exocortis

A

viroids

27
Q

are small infectious
proteins that cause fatal
neurologic diseases in
animals and humans (e.g.,
Scrapie, Bovine spongiform
encephalopathy [mad cow
disease], and Creutzfeldt–
Jacob disease).
• Of all pathogens, _____ are
the most resistant to
disinfectants.
• The mechanism by which
prions cause disease remains
a mystery.
• “Kuru” – laughing death

A

prions

28
Q

bacteria are divided into three major phenotypic categories

A

gram negative, gram positive, mycoplasma spp.

29
Q

three basic categories of bacteria used on SHAPE

A

COCCI, BACILLI, CURVEE AND SPIRAL SHAPED BACTERIAL

30
Q
  • in singly or in pairs (diplococci)
  • chains (streptococci)
  • clusters (staphylococci)
  • packets of 4 (tetrads) or packets of 8 (octads)
    about 1 um in diameter and some of it have “coccus in their name”
A

cocci

31
Q

• They are often referred to as rods; they may be short or
long, thick or thin, and pointed or with curved or blunt
ends.
• They may occur singly, in pairs (diplobacilli), in chains
(streptobacilli), in long filaments, or branched.
• An average sized bacillus is 1 x 3 μm.
• Extremely short bacilli are called coccobacilli.
• Examples of medically important bacilli:
Escherichia, Klebsiella, Proteus

A

BACILLI

32
Q

Examples of curved bacteria

A

Vibrio spp.
Campylobacter spp.
Helicobacter spp.

33
Q

• Examples of spiral-shaped bacteria

A

Treponema spp.
Borrelia spp.

34
Q

Staining Procedures
Three major categories of staining procedures

A
  1. Simple staining procedure
  2. Structural staining procedures
  3. Differential staining procedures
35
Q

two common techniques of fixation

A

heat fixation and methanol fixatiln

36
Q

gram positive

A

blue to purple (thick peptigolycan lauer)

37
Q

gram negative

A

pink to red (outer cell membrane washed off)

38
Q

who developed the staining procedure

A

hans christian gram

39
Q

is the red dye that is driven through the bacterial cell wall using heat

A

carbon fuchsin

40
Q

because mycobacteria are not decolorized by the acid-control mixture, ______

A

they are said to be ACID-FAST

41
Q

some are motile

A

rods

42
Q

all are motile

A

spirilla

43
Q

• If a bacterium is able to “swim,” it is
said to be motile.
• Bacterial ______ is most often
associated with flagella and less often
with axial filaments.
• Most spiral-shaped bacteria and about
50% of bacilli are motile; cocci are
generally nonmotile.
• Motility can be demonstrated by
stabbing the bacteria into a tube of
semisolid medium or by using the
hanging-drop technique

A

motility

44
Q

• A bacterial colony contains millions of organisms.
• _____ (appearance of the colony) varies from one species to
another.
• ______ includes size, color, overall shape, elevation, and the
appearance of the edge or margin of the colony.
• ________ can also include the results of enzymatic activity on various
types of media.
• As is true for cell morphology and staining characteristics, colony morphology is
an important “clue” to the identification (speciation) of bacteria

A

colony morphology

45
Q

Size of colonies is
determined by the
organism’s generation time
and is another important
characteristic of a
particular bacterial species.
Here, the generation time
is assumed to be ________

A

30minutes

46
Q

capnophilic organisms grow best in the presence of increased concentrations of CO2 usually

A

5-10%

47
Q

• All bacteria require some form of the elements such as carbon,
hydrogen, oxygen, sulfur, phosphorus, and nitrogen for growth.
• Some bacteria require special elements (e.g., calcium, iron, or zinc).
• Organisms with especially demanding nutritional requirements are
said to be fastidious (“fussy”).
• The nutritional needs of a particular organism are usually
characteristic for that species and are sometimes important clues to
its identity

A

true

48
Q

• As bacteria grow, they produce many waste products and secretions,
some of which are enzymes.
• Pathogenic strains of many bacteria, such as staphylococci and
streptococci, can be tentatively identified by the enzymes they
secrete.
• In particular environments, some bacteria produce gases such as
carbon dioxide or hydrogen sulfide.
• To identify bacteria in the laboratory, they are inoculated into various
substrates (i.e., carbohydrates and amino acids) to determine whether
they possess the enzymes necessary to break down those substances

A

biochemical and metabolic activities

49
Q

• Many pathogens are able to cause disease because they
possess capsules, pili, or endotoxins, or because they
secrete exotoxins and exoenzymes that damage cells and
tissues.
• Frequently, pathogenicity is tested by injecting the
organism into mice or cell cultures.
• Examples of some common pathogenic bacteria:
Neisseria meningitidis, Salmonella typhi, Shigella
spp., Vibrio cholerae, Yersina pestis, and treponema

A

pathogenicy

50
Q

• Laboratory identification of bacteria is moving toward
analyzing the organism’s DNA or RNA–techniques
collectively referred to as molecular diagnostic
procedures.
• The composition of the genetic material (DNA) of an
organism is unique to each species.
• DNA probes make it possible to identify an isolate without
relying on phenotypic characteristics.
• Through the use of 16S rRNA sequencing, the degree of
relatedness between two different bacteria can be
determined

A

genetic composition

51
Q

are bacteria, but they do not possess all the attributes of typical bacterial cells

A

rikkettsias, chlamydias and mycoplasma

52
Q

have a gram negative type of cell wall and are obligate intercellular pathogens (they must live within a host cell; they cannot grow on artificial culture media)

A

obligate intracellular pathogens

53
Q

have “leaky membranes” is _______
are “energy parasites” meaning they prefer to hse ATP molecules produced by their host cell

A
  1. ricketttsias
  2. chlamydias
54
Q

• They are the smallest of the cellular microbes.
• They lack a cell wall and therefore assume many shapes
(i.e., pleomorphic).
• In humans, pathogenic mycoplasmas cause primary
atypical pneumonia and genitourinary infections.
• Because they have no cell wall, they are resistant to drugs
like penicillin that attack cell walls.
• They produce tiny “fried egg” colonies on artificial media.

A

mycoplasma

55
Q

Photosynthetic Bacteria
Photosynthetic bacteria include purple bacteria, green
bacteria, and cyanobacteria; they all use light as an energy
source, but not in the same way.
• Purple and green bacteria do not produce oxygen,
whereas cyanobacteria do.
• Photosynthesis that produces oxygen is called oxygenic
photosynthesis.
• Photosynthesis that does not produce oxygen is called
anoxygenic photosynthesi

A

true

56
Q

discovered in 1977; they are prokaryotic
organisms.
• Genetically, archaea are more closely
related to eukaryotes than they are to
bacteria.
• Archaea vary widely in shape.
• Many archaea are extremophiles, meaning
that they live in extreme environments; e.g.,
environments that are extremely hot, dry, or
salty.
• Archaea possess cell walls, but their cell
walls do not contain peptidoglycan (in
contrast, all bacterial cell walls contain

A

the domain archaea true

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