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Viruses Flashcards

(59 cards)

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1
Q

Germ Theory

A
  • some diseases are caused by microorganisms
  • to small to see without magnifications
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2
Q

Pathogens

A

microorganism (germs) that causes diseases

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3
Q

types of Pathogens

A

viruses, bacteria, parasite, fungi, prions

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4
Q

characteristics of viruses

A
  • non living
  • contain either RNA or DNA and are surrounded by a protein coat
  • require host cells to reproduce
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5
Q

Nucleic Acid

A

DNA and RNA
- holds the key to genetic information for keeping viruses and allowing reproduction

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6
Q

nucleotides consist of…

A

phosphate, sugars and a base

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7
Q

RNA

A

single-stranded

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8
Q

DNA

A

double-stranded and strands form a “double helix”

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9
Q

what do DNA and RNA do with their genetic information

A

protein synthesis

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10
Q

protein synthesis

A

2 steps:
1. transcription: DNA is converted into RNA
2. translation: sequence of bases on the RNA will be “read” by the cell to produce proteins

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11
Q

what are proteins

A

molecules made up of individual units called amino acids
sequences of amino acids dictates the shape of the resulting protein

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12
Q

what do proteins do

A
  1. structural: can fit together and become part of a structure
  2. catalysts: proteins can speed up chemical reactions. their shape allows chemicals to fit into their “active sites” like a lock and key. from there chemicals are either bonded together or torn apart
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13
Q

what protein are used in catalyst function?

A

enzymes

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14
Q

where does transcription take place?

A

nucleus

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15
Q

where does translation occur?

A

ribosome

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16
Q

what is transcription?

A

where DNA is converted into RNA usi9ng the DNA to RNA base pairing rule

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17
Q

what is translation?

A

the strand of RNA leaves the nucleus and joins a ribosome, then known as the “messenger RNA or mRNA”

the cell “reads” the mRNA in groups of 3 called CODONS and a transfer RNA (tRNA) with a corresponding ANTICODON, delivers its specific amino acid to the ribosome. this process continues until a “stop” codon is reached

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18
Q

classification of viruses (3 types)

A
  1. DNA viruses
  2. RNA viruses
  3. retrovirus
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19
Q

what is a DNA virus?

A

contain DNA which will be the starting point of protein synthesis

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20
Q

what is an RNA virus?

A

contains RNA, which means the first step of protein synthesis, transcription, is “skipped” and the RNA enters translation

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21
Q

what is a retrovirus

A

“reverse transcription”: converts the viral RNA “backwards” into DNA then protein synthesis starts from the beggining

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22
Q

viruses that contain RNA are more unstable as they mutate or change in order of the bases

true or false

A

true

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23
Q

steps of the lytic cycle (4)

A
  1. virus attaches to cell and injects DNA
  2. viral DNA forms a circle inside cell
  3. new viral DNA and proteins are produced and assembled
  4. cell lyses, releasing virus

cycle repeats

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24
Q

steps of lysogenic cycle (3)

Study These Flashcards
A
  1. viral DNA inserts itself into the bacterial chromosome
  2. bacterium reproduces normally, replicating viral DNA at each cell division
    3a. cell and viral DNA are reproduced many times
    3b. occasionally the viral DNA separates from the bacterial chromosome, initiating a lytic cycle
25
what determines if a cell goes lytic or lysogenic?
the relative virulence, or ability to cause disease virulent: lytic cycle is initiated temperate: lysogenic cycle is initiated, triggers eventually causes the cell to go lytic
26
properties of lytic cycle (3)
- viral host replicates - host cells are destroyed - symptoms occur
27
properties of lysogenic cycle (3)
- DNA merges with host DNA - no viral replication - no symptoms
28
how do we prevent and fight infections
immunity is achieved when a pathogen enters a host, BUT that host fights it off before illness occurs
29
name and describe the 3 lines of defense
1. consists of the skin, acids and mucus membranes...no immunity yet 2. consists of white blood cells called phagocytes, as well as inflammation. IF the infection is more serious, a fever will occur 3. specific, system-wide, whole body fight that involves specialized white blood cells called B and T cells (key players in the Third line of defense)
30
where are B's and T's cells manufactured?
lymphatic system
31
where are B cells made?
made and matured in the bone marrow
32
where are T cells made?
bone marrow but they migrate to the Thymus to mature before entering the blood stream
33
antibodies
made in response to an antigen y-shaped proteins whose upper "tips" differ in shape. when an antigen triggers the formation of antibodies, only those antibodies with the corresponding shape will be produced *shape is virus specific
34
antigens
are part of an invader that triggers the production of antibodies
35
cell-mediated response
causes T cells to destroy body cells that have already been invaded by the pathogen
36
humoral response
causes B cells to produce antibodies which then attach to the antigens on the pathogen
37
passive immunity
ready-made antibodies only work short-term due to the lack of memory cells natural: maternal antibodies (ex through breast milk) artificial: antibodies from other sources (clinics have stored antibodies for lethal agents, like rabies and tetanus)
38
active immunity
produces memory cells natural: exposure to infectious agent (involves B and T cells - you produce your own immunity) artificial: vaccines
39
hygiene hypothesis
states that early childhood exposure to particular microorganisms protects against allergic diseases by contributing to the development of the immune system * not necessarily THE answer
40
if our immune system fights off viruses, why does death sometime occur? (3)
1. weakened immune system due to age, presence of other illness, etc 2. some viruses have evolved ways to block important parts of your immune system 3. sometimes a persons immune response is so strong that their own tissue (often lung tissue) is destroyed
41
how to fight back against death
preventions: vaccines treatment: antiviral drugs and/or monoclonal antibodies
42
chain of infection (6)
1. infectious agent (host) 2. reservoirs: where the pathogen "hangs out" 3. portal of exit: pathogen leaves the reservoir 4. means of transmission: transmit to a new host 5. portal of entry: pathogen enters a new host 6. susceptible host: pathogen transmit to a new host
43
chain of reaction: 3 targets
1. personal hygiene, immunization, prophylaxis 2. personal hygiene, sanitation 3. personal hygiene, isolation/quarantine, surveillance, treatment
44
what are vaccines?
introduce weekended or inactivated antigens from pathogens into your body in a safe manner. as a result, you do not get ill however you body "thinks" it is being invaded by pathogens which therefor creates antibodies to fight the "infection" off
45
4 types of vaccines
1. attenuated (weakened) live viruses 2. killed (inactivated) viruses or vaccines 3. toxoid (modified versions of toxins) 4. engineered vaccines
46
engineered vaccines
start by identifying the gene(s) that make up the antigen
47
3 types of engineered vaccines
viral vector, subunit and nucleic acid
48
engineered vaccines: viral vector
put it in another virus cells infected by the vaccine produce spike proteins as if they were infected by COVID
49
engineered vaccines: subunit
mass produce spike proteins
50
engineered vaccines: nucleic acids
make lots of copies of the spike protein genes
51
why are booster shots important?
gives another safe dose of the antigen so that more antibodies will be created, meaning greater and faster protection
52
what are the limitations with vaccines?
natural and ongoing mutations **think flu shots - always different vaccines for different mutations
53
why doesn't everyone get vaccinated (6)
medical, religious and/or philosophical grounds, lack of knowledge and/or understanding of the consequences, feel as though they "don't need it",
54
why do vaccines work (4)
1. benefits far outweigh risks 2. diseases you've never seen are still out there 3. individuals aren't vaccinated - populations are 4. herd immunity: the goal to protect those who are unable to get a vaccine
55
target #2 - modes of transmission (6)
1. vectors: mosquitoes, ticks 2. direct contact : STI's 3. direct contact: needles, tainted blood, animal bites, 4. fecal-oral route: poor hygiene, unsanitary water supply 5. food: poor hygiene, poor preparation 6. air: sneezing, coughing
56
what are antiviral drugs?
DO NOT KILL - disrupt the viruses pattern of attachment and lytic/lysogenic replications
57
6 ways antiviral drugs disrupt viruses
1. inhibit viral attachment 2. inhibit viral-cell fusion 3. inhibit uncoating 4. inhibit nucleic acid synthesis 5. inhibit proteases 6. inhibits the release of viral particles
58
antiretrovirals
subclass of antiviral drugs that can be effective against retroviruses like HIV
59
interferon
produced naturally during infections signals neighboring uninfected cells to destroy RNA and reduce protein synthesis signals neighboring cells to undergo apoptosis (cell death) activates immune cells

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