Bacteria + Archaea + Eukarya Flashcards
bacteria evolved
3.5-4 bill yrs ago
bacteria cause
- bubonic plague
- typhoid
- tuberculosis
- cholera
- gonorrhea
- lepsory
- botulism
- whooping cough
do bacteria have introns?
no
bacteria are
- opportunistic
- only cause illness when defense are weakened
linking diseases to bacteria began in the late 1800s. who was first to make this connection?
Robert Koch (used anthrax and tuberculosis)
Koch’s postulates (4)
- FIND SAME PATHOGEN IN EACH: researcher must find the same pathogen in each diseased individual
- ISOLATE PATHOGEN: isolate pathogen from diseased and grow in pure culture
- INDUCE DISEASE: induce disease into experimental animals by transferring the pathogen from the culture
- RE-ISOLATE: after (if) disease develops, re-isolate the same pathogen from experimental animals
super-bugs are aggravated/created by
excessive antibiotic use
beneficial prokaryotes
- prod vitamins
- decompose org material
- recycle nutrients (C, S, N)
how many bacterial cells have been found in oceans?
10^29
why are prokaryotes difficult to classify?
- limited fossil record
- structural simplicity
- DNA swapping (HGT)
phylogeny of prokaryotes is now determined by
sequencing regions of the SSU-rRNA
how small are bacteria?
200nm to 2microm
bacteria shape
- cocci
- bacilli
- spirilla and spirochetes
what do bacterial cell walls do?
- maintain shape
- protects from hypotonic envs
- contain peptidoglycan
bacterial movement
flagella
- convergent evolution with euk flagella
reproduction
- no sex
- binary fission
- speedy
bacterial genomes
- 1/1000th as much DNA as in euk genomes
- very little non-coding DNA (85% coding)
- genomic degradation
- circular chromosomes
- 20 000 genes
- approx. 3 billion chromosomes in genome
- 17 000 bp’s
how much of our DNA is non-coding?
98.5%
circular chromosomes
- 15% noncoding
- in nucleoid region
- not bound to histones
operon
cluster of genes under the control of a single promoter
plasmid
- small circular pieces of DNA
- 2000 to 10 000 bps
- can be horiz transferred
biotech: to amplify a gene of interest
- using recombinant DNA tech
1. cut gene out with restriction enzyme
2. put it into a plasmid
3. seal with DNA ligase
4. mix w/ bacteria
3 ways prokaryotes exchange DNA
- transformation
- transduction
- conjugation
transformation
- incorporate foreign DNA from surrounding env
- Frederickson
transduction
movement of genes btwn bacteria by bacteriophages
conjugation
- involves cell-to-cell contact
- sex pili allow DNA transfer
cDNA
DNA with introns removed = RNA + reverse transcriptase (used to make human insulin)
like bacteria, archaea have…
- no membrane-bound organelles
- circular chromosomes
- similar ribosomes
like eukarya, archaea have…
- no peptidoglycan
- introns (in some)
- have histones
archaea live in…
- low E envs
- marginal habitats
3 types of archaea
- methanogens (prod methane)
- halophiles (salty)
- thermophiles (hot)
phototrophs
obtain e from light
chemotrophs
obtain e from chemicals
autotrophs
need only inorganic CO2 to make org molecs
heterotrophs
need to consume at least 1 org molec
nitrogen fixation
- breaking the N triple bond and make it into NH3/NH4+
obligate aerobes
req O2 for cellular respiration
facilitative anaerobes
will use O2 if present, but can use fermentation
obligate anaerobes
poisoned by O2 and use fermentation
bacterial success
metabolic diversity & fast repro
euk success
diversity of shapes and sized, and fine control of gene expression
mixotrophs
photo + hetertrophic
dynamic cytoskeleton (3)
- faster/bigger
- change shape
- movement and phagocytosis
endomembrane system moves molecs faster or slower than diffusion?
faster
linear chromosomes (2)
- replicate multiple strands simultaneously
- large non-coding regions function in gene regulation
genetic diversity in bacteria is due to?
horizontal gene transfer
sex promotes diversity in euks in two ways
- gametes are genetically unique
2. fertilization is random
sperms differ from each other due to (2)
- recombination/crossing over
2. independent assortment
genetic diversity in euks
- dynamic cytoskeleton and membrane system
- complex gene regulation
- genetic diversity via sex
oldest euk fossils
1.8 bill yrs
problems with protista
- defined by exclusion
- poly/paraphyletic
- members not closely related
how many species of protists are there?
70 000 +
how do protists move?
cilia or flagella
protist diseases (4)
malaria, African sleeping sickness, amoebic dysentery, giardia
how did the endomembrane system evolve?
infolding the of the plasma membrane
endosymbiosis
proposes that mitochondrian and chloroplasts were independent prokaryotes
evidence that organelles were once free living
- appearance
- genomes
- enzymes
- ribosomes
- binary fission
secondary endosymbiosis
euk eating a euk that has eaten a prok and all retaining membranes
why discontinuous presence of Photosynth?
euks acquired Photosynth multiple times by repeated episodes of endosymbiosis
7 major superkingdoms of euks
- amoebazoa
- archaeaplastids
- opisthokonts
- stramenopila
- alveolate
- excavates
- rhizarians
ameobozoa contains
- amoebas
- slime molds
- cellular slime molds
Archaeplastida contains
- chlorophyta
- rhodophyta
stramenopila contains
- diatoms
- brown algae
alveolate contains
- dinoflagellates
- apicomplexans
- ciliates
excavates contains
- euglenids
- trypanosomes
- diplomonads
amoebozoa characteristics
- many are unicellular
- found in soil and aquatic envs
- use phagocytosis
- reproduce via mitosis or nuclear fusion
amoebas
- lobe shaped pseudopodia
- unicellular heterotrophs
- amoebic dysentry
slime molds
- fruiting bodies that prod spores
- plasmodial and cellular
cellular slime moulds
- good conditions, one-celled amoeba
- bad conditions, slug like thing
- individual/multicellularity
Archaeplastida characteristics
- cell wall w cellulose
- chloroplasts are surrounded by two membranes
chlorophyta
- green algae
- can be unicellular, colonial, or multicellular
- 10,000 species
rhodophyta
- no flagellated sperms
- live in deep w
- red
stramenopila characteristics
- have hair like projections on their flagella
- some heterotrophic, some photoauto’s
diatoms
- common phytoplankton
- chloroplasts have 3 membranes (2ndary endosymbiosis)
- glass-like walls of hydrated cilica
brown algae
- kelp
- complex anatomy similar to plants
- no vascular tissue
- convergent evolution
- Photosynth w “leaves”, using bladders to float them close to the sun
alveolata characteristics
- very diverse
- presence of cortical alveoli sacs under their membranes
dinoflagellates
- phytoplankton
- foundation of marine food chains
- spin b/c of 2 flagella in perpendicular grooves
- red tide
- zooxanthellae form mutualistic symbioses w/ corals and anemones
apicomplexans
- parasites (eg. plasmodium, cicle cell anemia)
- intricate life cycles
ciliates
- diverse
- use cilia to move and feed
excavates characteristics
- basal flagella
- cytoskeletons
euglenids
- anterior pocket w 1/2 flagella
- often mixotrophic
- photosynth
trypanosomes
- African sleeping sickness
- freq changes in surface proteins prevent host developing immunity
diplomonads
- lack mitochondria (lost 2ndarily)
