viruses & fungi

host range, narrow & broad

How many diff kinds of species a virus can infect

narrow = very few (1-2)

broad = many

Tissue tropism

what kind of cells a virus can infect (respiratory, etc)

parts of virus structure (2 parts)

\-capsid surrounds genome. Made of protein

\-some have envelope with spike protein for attachment

what kinds of viral genomes are there (how genetic info stored)

RNA or DNA

single stranded (ss) or double stranded (ds)

(-) oriented 3’-5’ or (+) oriented 5’-3’

Icosahedral virus

\-radial symmetry (circle)

\-fixed size

\-naked or envelope

\-some have spike proteins for attachment

filamentous virus

\-helical symmetry

\-helical tube around genome

\-variable size → flexible

\-size can increase based on genome

amorphous virus

\-no symmetrical form

\-most flexible

\-NO capsid, but HAS envelope

\-has “core wall” under envelope (similar to cytoplasm in cells)

(example: flu)

tailed bacteriophage virus

\-only infects bacteria

\-DNA stored in head, tail used to attach & inject

\-ALWAYS HAS *DS DNA GENOME*

antigenic drift

when a virus evolves and mutant proteins no longer recognized by host antibodies → generates new strands of virus

3 levels viruses evolve in

\-community: evolve to infect diff species → increase host range

\-within a species: evolve to be more infectious → antigenic drift

\-within an organism: evolve variants that resist meds → infect tissue

5 steps to ALL virus life cycle

1) attachment to cell

2) penetration

3) synthesis of new material in cell

4) assembly of virus in cell

5) release virus

what is lytic infection vs lysogenic infection

lytic = normal infection cycle

lysogenic = bacteriophage NA into host DNA during replication. slower. then a stimulus activates it and all cells with viral genes in DNA become infected suddenly

*PROK ONLY*

prokaryote viral infection steps (image)

euk viral infection steps (image)

ss and ds go to the _____ for replication

nucleus

DNA virus goes to the ______

nucleus

RNA virus goes to the _____

cytoplasm

persistent infection

when cell doesn’t die and lyse, instead virus keeps being made and released out of cell. *EUK ONLY*

Latent infection (latency period)

when virus doesn’t produce virions for long periods. (ex. HIV or herpes). *EUK ONLY*

LATENT infects ____ cells, while LYSOGENIC infects ____ cells

(prok or euk)

latent = EUKARYOTIC infection

lysogenic = PROKARYOTIC infection

Antigenic shift

when a host picks up a disease from 2 diff species at the same time. the 2 strains combine and make a new variant thats highly infectious

(ex. when a pig gets the flu from humans and bird at the same time)

antivirals work best if _____

if taken 24-48 hr after symptom onset

are fungi prokaryotic or eukaryotic

eukaryotic

4 structures unique to fungi

cell wall =chitin, glucan (sugar), mannoprotein

cell membrane = ergosterol

filamentous

multicellular, mold (& spores)

filaments are called ____

hyphae

hyphae make spores called ____

conidia

aspergillus

\-lung infection

\-breathe in from spores

\-greater affect ppl with lung problems (COPD, smoker, allergies)

\-grows everywhere = soil, produce, mold on walls

nonfilamentous

single cellular, yeast

yeast in bread is called ____ while infectious yeast is called ____

bread = saccharomyces

infectious = candida

thrush

yeast mouth infection

many antifungals target

ergosterol & chitin since they are not found in humans