Acellular microbes Flashcards

1
Q

the smallest virus is about the size of

A

large hemoglobin molecule of RBC

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2
Q

genome of a typical virion consists of

A

either DNA or RNA surrounded by capsid

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3
Q

nucleocapsid =

A

nucleic acid + capsid (protein coat)

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4
Q

features that distinguish viruses from living organisms

A
  • lack of enzymes necessary in energy production
  • unable to replicate on their own
  • depend on the resources of host cells
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5
Q

which type of viruses is more resistance to adverse conditions, why?

A

nonenveloped (naked) viruses, since attachment proteins are on the capsid (stronger than envelope)

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6
Q

single-stranded positive sense RNA functions as

A

mRNA in viruses

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7
Q

Bacteriophages

A

bacterial viruses (viruses that infect bacteria)
vibrio cholera

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8
Q

virulent bacteriophages

A

always causes a lytic cycle which ends with the destruction of the bacterial cell

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9
Q

temperate phages (lysogenic)

A

Their DNA remains integrated into the bacterial cell chromosome
 do not immediately initiate the lytic cycle like Virulent bacteriophages

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10
Q

latent virus

A

viruses that do not initiate biosynthesis right away

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11
Q

cold sores (latent virus infections)

A

cold sores (fever blisters)
 Caused by Herpes simplex virus I (HSV I)
 the cold sores come and go

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12
Q

what are the triggers for latent virus infections

A

fever, sunlight, or excessive stress

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13
Q

genital herpes

A

caused by Herpes simplex virus II (HSV II)

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14
Q

shingles

A

painful nerve disease
 Caused by Varicella zoster virus (VZV)
 Causes chickenpox (Varicella) as primary infection
 when the body’s immune defenses become weakened by old age or disease, the latent chickenpox virus resurfaces to cause shingles (zoster)

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15
Q

Epstein-Barr virus (EBV)

A

a type of herpes virus
 causes infectious mononucleosis (not a type of cancer)
 causes three types of human cancers:
a-nasopharyngeal carcinoma
b-Burkitt lymphoma
c- B-cell lymphoma

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16
Q

human herpesvirus 8 (HHV-8)

A

Kaposi carcinoma: cancer common in AIDS

17
Q

hepatitis B and C (HBV or HCV)

A

hepatocellular (liver) carcinoma

18
Q

Human papillomavirus (HPV) (DNA VIRUS)

A

Causes cervical cancer and other parts of the genital tract

19
Q

Retrovirus (RNA virus)

A

They have enzyme reverse transcriptase which turns RNA to DNA which
is integrated into the host cell genome
● They have long incubation periods
● Examples:
a. HIV→ AIDS → making patients immunocompromised and more
prone to cancers
b. Human T-lymphotropic virus type 1 → causes T-cell leukemia

20
Q

to what receptor does HIV bind to

21
Q

anti-P24 antibodies

A

very specific test to identify HIV
marker: major capsid protein (p24)

22
Q

Mimivirus

A

giant virus recovered from amebas (host)
‘mimics’ bacteria
contain DNA and RNA

23
Q

Megavirus

A

has the largest capsid diameter (440 nm)
the largest and most complex genome of all viruses

24
Q

inclusion bodies

A

remnants viruses seen in infected cells
used as a diagnostic tool

25
cytoplasmic inclusion bodies
- negri bodies (in nerve cells) → seen in rabies - Guarnieri bodies → in smallpox - Inclusion bodies seen in AIDS or HIV
26
intranuclear inclusion bodies
- Owl eyes → seen in cytomegalovirus - Herpes virus and poliovirus inclusion bodies
27
antiviral agents
drugs used to treat viral infections disrupts critical phases in viral cycle
28
viroids
infectious RNA molecules (only in plants) smaller than viruses
29
Prions
small infectious proteins that convert normal protein molecules into non-functional ones
30
Ebola virus
transmitted by bats, causes hemorrhagic fever, high mortality
31
Zika virus
transmitted by mosquitoes responsible for a large number of birth defects