diversity: prokaryotes and protists Flashcards
prokaryotes are ____cellular, ____ than eukaryotes, and _______ organelles.
unicellular, smaller, do not have
do prokaryotes have cell walls?
yes they form cell walls used for structure and defense
what are prokaryote cell walls made of?
peptidoglycan (sugar polymer) glued together by peptide chains
gram positive prokaryotes have __ cell walls
thick (many layers)
gram negative prokaryotes have __ cell walls
thin
gram negative prokaryotes
-more complex since they have a second membrane outside the wall
many prokaryotes are surrounded by a _________…
sticky layer: made of sugar chains or proteins
capsule
well organized sticky layer that forms a dense, protective layer
slime layer
less organized sticky layer
endospores form when
environment is harsh
what do endospores consist of?
chromosomes packed into dry structure
all metabolisms stops
can rehydrate when environment improves
how can prokaryotes move?
fimbriae, pili, or flagella
fimbriae
hairlike appendages that grab surfaces or other cells
pili
longer projections used to pull cells together to exchange DNA during conjugation (kind of like reproduction)
flagella
spinning structures used for swimming
DNA in prokaryotes is located where?
nucleoid (not nucleus): region of cytoplasm containing DNA
DNA is prokaryotes: chromosomes
single circular chromosomes
plasmid
seller pieces of DNA with additional genes
prokaryote reproduction
they reproduce asexually via binary fission which is where one divides into 2 clones
how often can binary fission occur?
most can divide every 1-2 hours: in 1 day, 15 million can be made starting from 1 cell
rapid reproduction leads to
rapid mutations: a mutation with a 1 in 10 million chance would still happen in less than a day
genetic recombination in prokaryotes
transformation, transduction, or conjugation
transformation
-take DNA from environment
-search environment for DNA from related species and can swap absorbed alleles with their own
transduction
viruses carry genes between prokaryotes
-virus picks up prokaryote DNA by mistake
conjugation
prokaryotes attach to each other and transfer DNA
-long pilus used to attach cells
-DNA transfer is one way
-requires F factor genes (instructions for process)
phototrophs
capture energy from light
chemotrophs
capture energy from chemical bonds
autotrophs
capture inorganic carbon and turn it into carbon molecules
example of how plants are autotrophs
they used Calvin cycle to take CO2 into useable materials
heterotrophs
required carbon compounds produced by autotrophs
photoautotroph:
-energy source?
-carbon source?
-light
-CO2 or bicarbonate
chemoautotroph
-energy source?
-carbon source?
-chemical bonds
-CO2 or bicarbonate
photoheterotroph
-energy source?
-carbon source?
-light
-organic molecules
chemoheterotrophs
-energy source?
-carbon source?
chemical bonds
organic compounds
_______ are most common followed by _____
photoautotrophs; chemoheterotrophs
obligate aerobes
- Uses oxygen for cellular respiration
- Requires oxygen for long term survival
obligate anaerobes
- Do not use oxygen for cellular respiration
- Use only fermentation or use atom other than oxygen for respiration (S or N)
facultative anaerobes
-use oxygen for cellular respiration if available
-uses fermentation if oxygen is not available
eukaryotes can only use nitrogen in a few forms, but prokaryotes…
can use nitrogen in many forms
some prokaryotes are most self sufficient organisms:
-use light for energy
-use CO2 for carbon
-use N2 for. nitrogen
*do not need anything from other living organisms
metabolic cooperation: some species cooperate in colonies
a few individuals fix nitrogen (same species)
biofilms
recruit other cells to join (many species)
create sticky molecules that stick to other molecules/surfaces
leave open channels for wastes and nutrients
very resilient
protobacteria
-grouped via genetic evidence
-very diverse
chlamydias (bacteria)
parasites that have to live in animal cells
-depend on host cell for ATP
-they lack peptidoglycan (no cell wall)
spirochetes (bacteria)
-spiral shape
-many are free living (not parasitic)
-some are parasites
cyanobacteria (bacteria)
-the only prokaryotes with photosynthesis
-AKA blue-green algae
-abundant in phytoplankton
gram positive bacteria
thick cell wall
very diverse
Archae
prokaryotic but some share some features with eukaryotes such as having introns and DNA wrapped w histones
in bacteria, you don’t have to process mRNA after transcription. but, in archaea…
you do since they contain introns that need to be removed
extremophiles
live in extreme environments (many archaea)
halophiles
live in salty environments
thermophiles
live in hot environments
methanogens
produce methane
protists: no longer a true..
phylogenetic group
protists do or don’t have internal structures?
yes they do, so they are eukaryotes
protists are: eukaryotes or prokaryotes?
eukaryotes
protist structure
eukaryote cell with organelles
most are unicellular (can form colonies)
more diverse in structure and function than plants, fungi, or animals
protists
excavates
o Grouped based on DNA evidence
o Some have a groove on the side for feeding
diplomonads and parabasalids
Have really small mitochondria
They do cellular respiration differently; they don’t use oxygen.
euglenozoans have
unique flagellum
SAR grouped based on
DNA evidence
SAR stands for
Stramenophiles
Alveolates
Rhizarians
stramenophiles
- Important photosynthesizers
- Have two flagella: one smooth and one hair
stramenophiles includes:
diatoms (unicellular algae in a complex glass shell)
golden algae (carotenoids, important phytoplankton)
brown algae: multicellular, largest and most complex algae
brown algae lack
true tissue or organs
structure of brown algae
holdfast, Stipe, Blades
alternation of generations
haploid cells grow into multicellular individual
how does alternation of generations work?
Diploid sporophyte makes haploid spores
Haploid gametophyte makes haploid gametes
Fertilization creates diploid sporophyte
dinoflagellates
Important phytoplankton
o Cellulose walls
o 2 flagella
apicomplexans
animal parasites
o Complex lifestyle with multiple hosts
ciliates
predators that move using cilia
alveolates include
dinoflagellates, apicomplexans, and ciliates
rhizarians include
radiolarians, foraminiferans, cercozoans
many rhizarians use
amoeba movements (crawl with pseudopodia)
radiolarians
o Internal glass skeleton
o Radiating pseudopodia for feeding
foraminiferans
o Porous calcium carbonate shells
o Form chalk
cercozoans
o Important bacterial predators
o Feed with pseudopodia
red algae
-has red photosynthetic pigment and chlorophyll
-can live deeper than most algae since they capture more blue light
-most are multicellular
green algae are closely related to
plants
some green algae are unicellular:
phytoplankton
live in damp terrestrial environments
symbiotic
some green algae are colonial
live together but they do not HAVE to
often long filaments
red and green algae often have complex lifecycles with
sexual and asexual reproduction
unikonts
o Diverse clade (common ancestor and all the things that come from that)
o Includes various protists
Amoebozoans
o Clade also includes fungi and animals
amoebozoans: plasmodial slime molds
One giant cell with many nuclei
Often colorful
Decomposer of plant material
Create fruiting bodies
amoebozoans: cellular slime molds
Function as individuals for feeding
Function as a group to form spores
