L9 - Viruses and Eukaryotes Flashcards Preview

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Flashcards in L9 - Viruses and Eukaryotes Deck (13):

What is the outer layer of a virus called and what is it made up of?

Capsid- made up of protein subunits called capsomeres


What is the outer coat of some viruses made up of?

Surface proteins and lipids


Name and briefly describe the intracellular and extracellular versions of a virus

Extracellular = viron/virus = inert particles carrying out neither metabolic or biosynthetic activities
intracellular = once intracellular the virus DNA/RNA becomes active and replicates inside the host


What 2 types of lifecycle can a virus have? Describe each briefly

1) lytic - once inside the cell, the virus replicates its DNA and capsids, puts the DNA inside the capsid then lyses the cell and the phages are released
2) lysogenic - once inside the cell the viruses DNA integrates into the hosts DNA, so when the cell replicates the virus is replicated as well


What is a viron?

A viron is a small circular single stranded RNA - smallest know pathogen
Important plant protein


What is a prion?

A prion is an extracellular infectious protein
Causes scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle and kuru and new variant form CJD in humans.


What is the structure called how most fungi grow?



What is meant by the fact fungi are dikaryons?

Their + and - nuclei fuse, undergo meiosis and form fruiting bodies


Briefly describe Chytridio-mycota

Play a key role in the breakdown of rumen in cows.
Can be a lethal parasite to tree frogs
Don't have hyphae


Briefly describe Zygomycota

Mostly saprotrophs, some important plant (Rhizopus) and human (Mucor, Absidia) pathogens
Have broad hyphae
Asexual spores produced in pin-head-like sporangia


Briefly describe Glomero-mycota

Widespread on roots of herbaceous plants (earliest known fossil fungi), share nutrients


Briefly describe Ascomycota

Have spetated hyphae
These produce 8 ascospores in sac-like asci.
Include cup fungi – but also yeasts and many micro fungi.
Many are important plant pathogens.
Includes Penicillium


Briefly describe Basidomycota

Pistol fungi – rusts, smuts mushrooms & toadstools
These are the most highly evolved fungi – have septate hyphae with clamp connections
Spores produce on pistol-like basidia bearing 4 basidiospores