Virus & Fungi

Question 1

what is a virus?

Answer 1

need host to replicate

- little cellular machinery, no cell division - just self assembly - mutuates to adapt to host better.

Question 2

viral classification

Answer 2

• dna vs rna
• linear, circular, segmented
• ss/ds +/- sense
• • enveloped or not**

Question 3

General life cycle of virus

Answer 3

1 attachment

2. entry – uncoating
3. replication, translation
4. assembly
5. release

Question 4

lytic cycle

Answer 4

step 3. translation focused on viral proteins, not cellular proteins = weakens cell.

4. self-assembly
5. weak cell - can lyse out our budd off. both ways weakening the cell further. bud off = keep intact factory for viral growth.

Question 5

lysogenic cycle

Answer 5

3. no repln, transln = instead, integrate pro-virus into host DNA. duplication of host will allow pro-virus to duplicate too. more cells have viral in DNA. slowly propagates self. viral DNA reemerges when immunocompromised. opportunistic.

Question 6

ex: Dna virus
ex: rna virus

Answer 6

dna = vzv = chicken pox
rna = mmr

Question 7

transmission : airborne

Answer 7

best for droplets. both DNA and RNA transmitted. large or small droplet

Question 8

transmission: GI, fecal-oral

Answer 8

transmitted by aerosols. high concentration can spread well. mostly RNA.

Question 9

transmission: contact

Answer 9

probs have membrane - need close contact to pass on & not die. mostly DNA ex: VZV.

Question 10

transmission: sexual

Answer 10

RNA - mostly DNA

Question 11

transmission: blood -borne

Answer 11

needle-stick injury in hospital.

Question 12

insect vecotr

Answer 12

mosquito malaria

Question 13

disease manifestation- latency

Answer 13

virus may co-existwith human cells without disease, viral replication coincides with host cell division

Question 14

diseas manifestation- active infection

Answer 14

cell dmaage and disease, acute cell necrosis, cell hyperplasia and proliferation

Question 15

fungal - target of antifungals

Answer 15

ergosterol and cell structure.

Question 16

yeast

Answer 16

single cell - bud by asexual reproduction. round.

human disease, yeast infections are typically from our GI flora

Question 17

moulds

Answer 17

filamentous, multicellular branching.
aspergillus. environmental - conidia bud off easily.
asexual spores, easily airborne, transmission: allergy, infection
infection source is environmental

Question 18

superficial infection

Answer 18

dermatophyte = fungi parasatize skin, hair nails.

eX: ringworm, dermatophystosis, cutaneous mycosis

Question 19

subcutaneous infection

Answer 19

gardeners thumb - spore in thumb = deep ulcerated skin lesion

Question 20

opportunistic infection

Answer 20

not true pathogen, low virulence. need immuno-compromised = aspergillus

Question 21

invasive

Answer 21

true pathogens cause severe disease. dimorphic types.

Question 22

host defines mechanisms

Answer 22

cytokines, interferons, humoral immunity (Ab), vaccine

Question 23

antiviral agents

Answer 23

DNA/RNA synthesis
prevention of protein coating
activation of host responses (interferon)

Question 24

What is fungus?

Answer 24

eukaryotic microorganisms, 50 species cause human disease, larger than bacteria

Question 25

Three main fungal forms

Answer 25

yeast - single cell, asexual budding
mould- multicellular, filamentous, asexual
dimorphic form- mold at RT, yeast at body temp