Topic 9 - Viruses & prokaryotes Flashcards
Differences between bacteria & archaea
mainly biochemical/ultrastructural
- bacteria contain PEPTIDOGLYCAN
- structure - plasma membranes, ribosomes, RNA poly.
- mechanisms of transcription/translation
Special adaptations…
- flagella
- formation of biofilms - sticky slime for adhesion to stuff eg. dental plaque
- formation of endospores - protective enclosure; withstand extreme temps.,
- tolerant to many environmental extremes
- diverse metabolism - mainly anaerobes, some facultative aerobes, obtain nutrition from all over (those toxic to vertebrates & inorganic molecules)
- photosynthesis - cyanobacteria
- rapid reproduction - binary fission
- exchange of genetic material
Role in animal nutrition…
digestion of cellulose
production of cheese, yoghurt, sauerkraut
wine fermentation (these things are awesome!)
vitamin K & B12 synthesis
Role in plant nutrition…
nitrogen-fixing bacteria (nitrogen -> NH4 ot AAs)
Role in ecosystems…
decomposers
useful in bioremediation (feed on toxins -> liberate simple nutrients)
Beneficial interactions with humans (important q)…
skin/gut microflora food prod. meds - ABs Agriculture (nitrogen fixation) bioremediation
Detrimental interactions with humans (important q)…
MRSA (S. aureus) meningitis STDs ulcers Legionnaire's disease tetunus botulism diptheria TB
Major epidemic caused by prokaryotes…
Black death Caused by Yersinia pestis Carried by rats transmitted thru flea bites high mortality - bubonic (lymph 30-75%) - pneumonic (lungs 90-95%) - septicemic (blood 100%) death in 4-7 days!!!
A bit about viruses… (what don’t they have)
no cellular structure
no ribosomes
no cytoplasm
no capacity to obtain energy from fuel molecules
no membranes
no unable to grow or reproduce on their own
Structure of viruses…
protein shell (many geometric shapes) genetic material (DNA or RNA, linear or circular)
Viral replication…
Takes over genome of host cell
Diseases of viral origin…
cold - rhinovirus
flu - influenza virus
AIDS - HIV
enchephalitis
Types of virus…T4 bacteriophage contains
DNA head tail fibres (often) infect bacteria helped in molecular biology
What are viroids?
simpler than viruses
consist simply of genetic material (circular)
most are plant diseases
What are prions? eg of disease
weird mo fo’s!
simply a misfolded protein (no genetic material)
can induce normal proteins to change to same misfolded protein -> build up in nerve cells -> abnormal nerve function
Bovine spongiform encephalopathy (BSE) “mad cow disease”
