Exam 1: Viruses, Bacteria & Archaea, Protists, Fungi Flashcards
taxonomy
the practice and study of classification of things or concepts + the principles that underlie such classification OR putting things into diff categories as a means of organization
two main schools of thought
lumpers - group critters into as few groups as possible
splitters - split critters into as many groups as possible
taxonomic hierarchy
domain kingdom phylum class order family genus species
dumb king philip can only find green socks
taxa
a group of critters at a given taxonomic level
species
a group of like critters that can reproduce and produce viable offspring
classification systems/historic people
aristotle - 4th century greek philospher, grouped into plants and animals, divided animals into blood and bloodless, divided animals into movement with flying, walking, and swimming system used until mid 1600s
Linnaeus 18th century created binomial nomenclature
Charles Darwin in 19th century, theory of evolution/adaptation “the origin of species”
phylogeny
the evolutionary development and history of a species or higher taxonomic grouping of organisms
OR
the taxonomic classification mirroring the evolutionary development
cladistics
tries to show evolutionary relationships based on physical traits shared by different groups of organisms
15.1 Viruses are Infectious Particles of Genetic Info + Protein
a. smaller and simpler than cells (12x smaller than bacterium)
- all viruses have genetic info + protein coat (capsid)
some may have an envelope
B. host range consists of the organism it infects
- can enter only a cell that has a specific receptor
all species get viral infections
reservoir of a virus is the site where it exists in nature
C. Are viruses alive>
- most do not consider them to be
- don’t metabolize, respond to stimuli, or reproduce on their own
- do have genetic material and mutate -> natural selection
- not part of taxonomic hierarchy, instead grouped by chemical similarities
15.2 Viral replication occurs in 5 stages
- attachment
- penetration
- synthesis
- assembly
- release
amount of time varies
draw and label all 5 steps of viral replication within a cell
refer to figure 15.2 in notes/lect slides
15.3 cell death may be immediate or delayed
A. some viruses kill cells immediately
- lytic infection/pathway
- virus enters cell + immediately replicates and lyses host
- “phage therapy” for bacterial infections - unlikely to acquire resistance, targeted to specific bacteria, studied by USSR
essentially viruses that selectively target bacteria
B. Viral DNA may also hide in a cell
- lysogenic infection/pathway
- genetic material of a virus is replicated along with the host cells chromosome
- prophage
- host not immediately destroyed
- can also switch to lytic pathway
15.4 Effects of a Viral infection may be mild or severe
A. Symptoms may result from cell death + immune response
- incubation period = the time between exposure to disease agent and disease signs and or sympyoms
- influenza virus -> flu
- dead + damaged cells in airway cause the respiratory symptoms of influenza -> cough + sore throat
- fever + body aches caused by cytokines released by immune systems
B. some animal viruses linger for year
- latent infection does not produce disease symptoms
- viral genetic info inside cell
- herpes simplex virus type I
- cold sores on lips, stressed cells release viruses that infect other cells, cold sore localized death of these cells
- HIV
- retrovirus - uses reverse transcriptase
- RNA genome
- infects helper T cells
- loss of these cells leads to AIDS
- Human papillomavirus causes cervical cancer by signaling host cell to divide continuously
C. Drugs and Vaccines help fight viral infections
- some antiviral drugs interfere with enzymes or other proteins that are unique to viruses
few medicines inhibit viruses without killing infected host cells
complicated by genetic variability by viruses
vaccination teaches immune system to recognize virus
childhood vaccinations greatly reduced or eliminated viral infections
fertilized chicken eggs used to produce viruses
epidemic, pandemic, and endemic
more cases of disease than expected
widespread, worldwide epidemic
disease outbreak that is consistently present
HIV
human immunodeficiency virus
AIDS
acquired immunodeficiency syndrome
origin of HIV
raw bushmeat (monkeys), origin in SF LGBTQ+ community
15.5 Viruses Cause Diseases in Plants
- first virus ever discovered was tobacco mosaic virus
- most spread by plant-eating insects
- spread through plasmodesmata
- can use post-transcriptional gene silencing to fight off infections
Rabies
Rabies is a viral disease that causes acute inflammation of the brain in humans and other mammals
incubation period typically 1-3 months
infection via animal bites
- hydrophobia - difficulty swallowing
99.99+ % fatal (<6 human survival cases EVER, 4 in last 5 years)
Vaccine is very effective if given early enough
US human (fatal) cases 1-3/year
Ebola
Originated in central africa - blood vessels break down, internal bleeding, extreme bleeding and ultimately death
zika virus
mosquito-transmitted; (RNA)
associated with microcephaly (mechanism unknown)
- mild to significant learning disabilities
- impaired motor functions
- difficulty with movement and balance
- speech delays
first isolated in uganda in the zika forrest - 1947
brazil 2015 - 3.500 cases (47 fatal)
15.6 Viroids and Prions are other noncellular infectious agents
A. A Viroid is an infectious RNA molecule
- naked RNA
- does not encode proteins
- interferes with ability to produce proteins
B. A prion is an infectious protein
- abnormal form causes brain cells to die
- spongiform encephalopathies
- mad cow disease (BSE)
- human forms
- kuru - cannibalism
- creutzfield-Jakob disease (CJD)
- fatal familial insomnia
monkeypox + smallpox
within 1-3 days after appearance, patient develops rash, often beginning on the face then spreading
illness typically lasts 2-4 weeks
monkeypox disovered 1958 in africa, dna virus, mortality <10%
presents like chicken pox and mild smallpox
cross-immunity with smallpox
smallpox - 30% fatality, successful vaccine in 1797, completely eradicated in 1977, still exists in labs
16.1 Prokaryotes are a biological success story
Prokaryote
- single celled organism that lacks a nucleus and membrane-bounded organelles
2 prokaryotic domains
- bacteria
- archaea
16.2 prokaryote classification traditionally relies on visible features
A. Microscopes reveal cell structures
internal structure
- cell membrane, DNA, cytoplasm, ribosomes
- nucleoid
- plasmids
external structure
- cell wall
- peptidoglycan
- 3 common shapes
- coccus, bacillus, spirillium
- arrangements can also be important
external structures
- gram stain
- gram positive
- thick peptidoglycan layer
- gram negative
- thinner cell walls
- outer membrane
glycocalyx
- capsule or slime layer
pili
- attachment or DNA transfer
flagellum
- not the same as eukaryote
endospores (little particles that work like seeds, but are not seeds)
- dormant, thick-walled structures
- clostridium botulinum
- botulism
- bacillus anthracis
- anthrax
B.metabolic pathways may be useful in classification
autotrophs
- carbon from inorganic sources
heterotrophs
- carbon from organic sources
phototrophs
- derive energy from sun
chemotrophs
- oxidize inorganic or organic chemicals
photoautotroph
- plants and cyanobacteria, ALGAE
- sunlight for energy and CO2 for carbon
chemoheterotroph
- disease-causing bacteria use host as carbon and energy source
oxygen requirements
- obligate aerobe
-obligate anaerobe
-facultative anaerobe
C. molecular data reveal evolutionary relationships
- revolution in microbial taxonomy
- used rRNA sequences
- closer to taxonomy
16.3 Prokaryotes transmit DNA vertically and horizontally
vertical gene transfer
- transmit DNA from generation to generation as they reproduce
- binary fission (asexual)
horizontal gene transfer
- transformation
- naked DNA
- transduction
- virus mediated
- conjugation
- sex pilus
16.4 - START HERE AT SLIDE 19 AND FILL IN UNTIL CAUGHT UP !
Cholera
water-borne
death from dehydration in as few as 12 hours
vibrio cholerae - gram negative rod; facultatively anaerobic
extremely severe diahrea
global transportation
cholera - can spread worldwide rapidly with modern transportation
nepal haiti 2010 outbreak
lous pastear ADD IN
Joseph Lister 1827-1912
English Surgeon
applied pasteur’s discoveries beginning 1865
developed antiseptic surgical techniques - 5% carboxic acid
“Listerine” - 1879 marketing idea (not his)
Robert Koch 1843-1910
determined that different species of bacteria cause different diseases
developed rigorous proofs (postulates) to determine which bacteria caused which disease
the bacteria must be present in every case of the disease
the bacteria must be isolated from the host with the disease grown in pure culture
the specific disease must be reproduced when a pure culture …… COMPLETE
GO BACK AND LOOKOVER SLIDES AS NEEDED!
16.5 INPUT HERE
Good - Food and Medical Uses
acetobacter e al -> EtOH acetic acid
vinegar
sauerkraut
kimchee
biotech
genetic engineering
revise and go back as needed!
17.1 Protists Lie at the Crossroads between simple and complex organisms
A. What is a protist?
- eukaryote that did not fit the description of a plant, fungus, or animal
- based on new molecular data, the former Kingdom Protista has shattered into dozens of groups whose relationship ….. GO BACK AND FINISH !!
B: Protists are important in many ways
- very metabolically diverse
- ecosystem FINISH HERE FINISH UP !
