Lecture 11 Key Concepts/Terms

what are the two characteristics of life?

1.) organization
2.) can replicate itself

helical capsid

virus structure
continuous helix of capsomers forming a cylindrical nucleocapsid
RNA strand inside

icosahedral capsid

virus structure
3D, 20 sided figure
DNA inside

Icosahedral head: helical tail

bacteriophage/bacterial virus structure
capsid at the head containing DNA

helical capsid within envelope

virus structure
capsid containing RNA

what structure is an adenovirus

icosahedral capsid

capsid/protein coat

encloses genetic material

Can a virus contain both DNA and RNA?

no, one or the other

what two configurations can viral genetic material have

circular or linear

can a virus have single or double stranded DNA/RNA?

yes

viruses evolve ________ from other organisms

independently

what is a binal virus

irregular in shape and have complex structures

what kind of virus structure is binal?

bacteriophage

helical viruses

rod-shaped viruses

icosahedral viruses

viruses with a polyhedral capsid with 20 triangular facets

bacteriophage

kind of virus that infects bacteria
cylindrical body with icosahedral capsid on tail fibers (alien looking)

viral replication is _______

independent of the host cell's DNA but dependent on the host cell's enzymes and metabolism (parasitic)

why do some scientists argue that viruses are not alive?

they can't multiply on their own to make offspring viruses

what is the significance of TSEs (transmissible spongiform encephalopathies) in this lecture?

they used to be referred to as "slow viruses" because they used to be undetectable until years after infection. TSEs are prions and prions have no genetic material. Bc of this, expression is restricted

what are some examples of TSEs?

Kuru, mad cow disease, scrapie, chronic wasting disease, creutzfeldt-jakob disease

how are prions different from viruses?

they only contain protein and they lack DNA or RNA

prion

abnormal pathogenic agents that are transmissible and induce abnormal folding of specific normal cellular proteins found mostly in the brain

How are prions transmitted?

ingestion, transplant, and surgical instruments

how is the traditional tree of life misleading?

it looks monophyletic, but it's not, it's paraphyletic

how should we think of the tree of life?

LUCA

last universal common ancestor; only on the tree of life

what are the traits shared by all life forms (before LUCA)

-plasma membrane bound cells
-ribosomes
-semi-conservative DNA replication
-similar genetic codes for proteins
-transcription and translation
-metabolic pathways

Are prokaryotes unicellular or multicellular?

always unicellular

How do prokaryotes divide?

binary fission

configuration of DNA in prokaryotes

circular chromosome, unenclosed DNA

do prokaryotes have organelles?

no

do prokaryotes sexually or asexually reproduce?

asexually

what are the three defining traits of eukaryotes?

they are multicellular
they have organelles (compartmentalized)
they are mostly sexual

How is the new eukaryotic tree different from older views?

you can find plants fungi and animals as tips on tree, other tips include protists