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MT 12 LEC > Lec 5: Diseases of the 21st Century > Flashcards

Lec 5: Diseases of the 21st Century Flashcards

1
Q

What is the smallest known infective agent?

A

Virus

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2
Q

What are the characteristics of a virus? (5)

A
  • Does not have a cellular organization
  • Contains only one type of nucleic acid
  • Obligate intracellular parasite
  • Lacks enzymes necessary for protein and nucleic acid synthesis
  • Unaffected by antibacterial antibiotics
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3
Q

What term refers to extracellular infectious virus particle?

A

Virion

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4
Q

What is the size of viruses? (compared to bacteria)

A

Much smaller than bacteria

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5
Q

Why are viruses referred to as Filterable and Ultramicroscopic?

A

▪ Filterable viruses since they can pass through filters unlike bacteria
▪ Ultramicroscopic, as they were too small to be seen under the light microscope

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6
Q

A virus cannot be categorized as prokaryote or eukaryote because it does not have a?

A

cellular organization

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7
Q

What do you call a virus outside the host cell which can do anything and is dormant and inactive?

A

Virion

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8
Q

A virus could be RNA or DNA but not?

A

not both

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9
Q

When can a virus be activated or when does it leave the dormant state?

A

When it interacts with a host cell

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10
Q

What is the capability of a virus to target/infect a host cell?

A

Host Tropism

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11
Q

When a virus gets inside body it does not infect directly, what does it do?

A

it chooses a certain host cell

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12
Q

What are the target host cells of HIV and HBV?

A

HIV - CD4 T cells
HBV - Hepatocytes in liver

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13
Q

When talking about the morphology of the virus, what must you consider?

A

The size and the shape

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14
Q

What is the unit of measurement of virion size and how does it compare to a bacteria?

A

unit of measurement of virion size is nanometers

  • viruses are much smaller than bacteria (micrometers)
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15
Q

What makes the filterbale viruses a disadvantage in the medical setting?

A

BSC don’t have the ability to filter them through the hepa filter

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16
Q

Viruses are Ultramicroscopic, as they were too small to be seen under the light microscope. This is true except for what type of virus?

A

except for the LARGEST DNA VIRUS: Poxvirus if stained properly
- for the rest you can use the ELECTRON MICROSCOPE

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17
Q

What is the smallest and largest DNA virus?

A

Smallest: Parvovirus
Largest: Poxvirus

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18
Q

What is the smallest and largest RNA virus?

A

Smallest: Picornnavirus
Largest: Paramyxovirus

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19
Q

What are the four shapes of a virus?

A
  1. Helical (or cylindrical)
  2. Isometric
  3. Enveloped
  4. Head and tail
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20
Q

What virus shape is typical among many plant viruses such as tobacco mosaic virus or TMV?

A

Helical

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21
Q

What is the shape of your poliovirus and herpes virus?

A

Isometric or icosahedral

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22
Q

What is the characteristic of an enveloped shape of a virus?

A

it has glycoprotein spikes that protrude on the plasma membrane

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23
Q

what shape of the virus have membranes derived from the host cell that surrounds the capsid such as hiv and coronavirus?

A

Enveloped

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24
Q

Identify

Viruses with this shape in fact bacteria and have a head-like icosahedral viruses and a tail-shaped like helical viruses. What’s an example of this?

A

Head and tail
ex: Bacteriophage

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25
What is the shape of your human rhinovirus or HRV 14?
Isometric or Icosahedral
26
What is the difference between enveloped and non-enveloped virus structure?
Enveloped - has glycoprotein spikes - Has Genome, capsid, nucleocapsid, spikes, tegument, envelop Non-enveloped - naked - do not have glycoprotein spikes - Only has GENOME, CAPSID, and NUCLEOCAPSID
27
What structure of the virus is also called the nucleic acid core which could either be RNA or DNA but not both?
Genome
28
what reference in the protein layers covering the genome of a virus?
capsid
29
What refers the terms used to describe the combination of genome and capsid as a structure of a virus?
Nucleocapsid
30
In an envelope virus, what must be present in order for the virus to infect a host cell?
Glycoprotein spikes or Peplomers
31
# Identify This refers the matrix separating envelop from nucleocapsid
Tegument
32
what is the external glycoprotein or lipid that is covering the nucleocapsid taken from the host?
Envelop
33
what structure of a virus is where the spikes protrude?
Envelop
34
Which type of virus is more resistant to changes in environment?
Naked virus
35
The naked virus is more resistant to extreme environmental conditions like?
pH, dryness, heat, simple disinfectant
36
What are examples of naked viruses?
Norovirus, Enterovirus, Adenovirus, Rhinovirus
37
Why are naked viruses considered more virulent?
more virulent because they cause POST-CELL LYSIS: once done replicating and go to other cells, the cell where they replicated will die
38
How are naked viruses and envelope viruses transmitted?
Naked: by fecal-oral route Enveloped: by respiratory inhalation, sexual or parenteral contact, or perinatal contact
39
What happens to enveloped virus when they go out of the host cell?
They die
40
what are the functions of peplomers?
1. Mediate attachment 2. Attach to receptors 3. Enzymatic activity 4. Major antigens: for protective immunity of the virus
41
what are the functions of capsid?
1. Protection 2. Binding sites 3. Facilitates assembly and packaging of viral genetic information 4. Vehicle transmission 5. Host defense 6. Provides structural symmetry to the virus particle (shape of the virus)
42
What type of genome does HIV have?
RNA
43
What viral glycoproteins are found in the envelope of the HIV structure and what is/are their function?
- gp120 and gp41(knob-like) - function: for host cell attachment
44
What protein protects the 2 ssRNA strands in the HIV structure?
p24 or the CORE PROTEIN
45
What are the 3 enzymes found inside the p24 or the Core protein that protects the ssRNA strands of an HIV virus?
1. p10 (protease) 2. p32 (integrase) 3. p64 (reverse transcriptase)
46
What enzyme inside the HIV virus integrates the double stranded DNA, that resulted from the uncoating of genetic material, to the host material? (reason why the virus can order around the host cell)
p32 or integrase
47
What is the most important enzyme found only in HIV?
p64 or reverse transcriptase
48
# Identify Without this, there is no way for host cell to follow the instructions of the virus - dli ka replicate ang virus of HIV
p64 or reverse transcriptase
49
What is the function of the p64 enzyme in HIV?
transcribes viral RNA to a double-stranded DNA - conversion of viral genomic RNA to double-stranded DNA
50
HIV belongs to what genus and family?
Belongs to the genus ***Lentiviridae*** of the virus family ***Retroviridae***
51
What virus is described as a spherical particle, 100-120 nm in diameter?
HIV
52
What is the #1 cause of death for people (bet. 20-35 yrs. old)?
HIV - 1
53
How is HIV-1 transmitted?
transmitted thru: - unprotected sex - contaminated blood or blood products - contaminated needles, or perinatal
54
HIV-1 is isolated from?
- mononuclear cells, - plasma, - semen, - cervical/ vaginal secretions, - saliva (barrels since its hypotonic and has salivary enzymes) - tears, - urine, - breast milk, - CSF, - lymph nodes, - brain, and - bone marrow.
55
How is vertical transmission of HIV-1 possible?
- from mother to child in utero - during delivery - breastmilk
56
HIV-2 is transmitted through?
- blood products - sexual contact, or - from mothers to infants
57
Majority of HIV cases are transmitted through?
Intimate sexual contact (either vaginal or anal intercourse)
58
In the US, the largest number of cases is the result of ___________. But 85% of HIV is attributed to _____________
- 85% of HIV is attributed to heterosexual contact - in US, the largest number of cases is the result of homosexual contact
59
What can increase the likelihood of transmission of HIV?
Presence of other sexually transmitted diseases such as syphilis, gonorrhea, or genital herpes
60
In male to male, if sex is rough, integrity of rectum is violated - abrasions can be a portal of entry of the virus. for vaginal intercourse - cervix is thin and prone to abrasions; and foreskin for males. Why do abrasions cause infection aside from being a portal of entry?
If there is abrasion - there will be disruption of the protective mucus membrane and increase in immune activation in the genital area (when body detects foreign antigen - the immune system attack and create antibodies)
61
PARENTERAL EXPOSURE TO INFECTED BLOOD OR BODY FLUIDS happens when there is?
- Sharing of contaminated needles by IV drug users - Blood transfusion or the use of clotting factors by hemophiliacs - Occupational injuries with needle sticks or other sharp objects - Mucous membrane contact in healthcare workers exposed to infectious fluids - Transplantation of infected tissues
62
Perinatal transmission of HIV has been markedly decreased through?
- HIV screening during pregnancy - Administration of antiretroviral drugs to HIV positive pregnant women and their newborn babies - Use of infant formula by HIV-infected mothers
63
How is HIV attachment to a susceptible host cell mediated?
Mediated through the host-cell CD4 antigen (receptor for HIV) by binding the gp120 and gp41 on the outer envelope of the virus
64
What are the main target cells of HIV?
T helper cells (CD4)
65
What other cells have CD4 molecules?
- monocytes, - macrophages, - dendritic cells, - Langerhans cells, - microglial cells of the brain
66
What is required for HIV to enter the host cell?
Requires chemokine receptors that promote fusion of HIV envelope with the plasma cell membrane
67
What are the chemokine receptors required for the fusion of HIV envelope wiith the plasma cell membrane?
- CXCR4 for T lymphocytes - CCR5 for macrophag
68
What happens during the uncoating of viral particle in HIV transmission?
- Exposed viral genome acted upon by RT producing cDNA from the viral RNA - cDNA is incorporated to the host cell’s genome known as provirus - Viral DNA is transcribed into genomic RNA and mRNA (transported to the cytoplasm)– - Translation of mRNA occurs, with production of viral proteins and assembly of viral particles
69
How does the HIV virus replicates to other host cells?
virus leaves the host cell after replication through acquiring an envelope if mufuse ang viral particle pagawas sa host cell and then it will infect another host cell
70
The signs and symptoms of HIV are characterized by?
a progressive decline of the immune system
71

MT 12 LEC (3 decks)

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