Lecture 2 (bacterial Cell structure with some Archaea stuff) Flashcards
Prokaryotes differ from eukaryotes in size and _____
simplicity
most prokaryotes lack
internal membrane systems
is the term prokaryotes becoming blurred
yes
prokaryote comes form the Greek words for
pre-nucleus
Eukaryote comes form the Greek words for
true nucleus
Are most bacteria monomorphic
Yes
What does monomorphic mean
one shape
Are a few bacteria pleomorphic
yes
what does pleomorphic mean
multiple shapes
What are the three basic bacteria shapes
- Bacillus (rod-shaped)
- Coccus (spherical)
- Spiral
what are the three types of spiral shapes
- Spirillum
- Vibrio
- Spirochete
What is Spirillum
Spiral shaped with one or more twists
What is Vibrio
type of Spiral shaped
-Curved rod
What is Spirochete
- Type of Spiral shape
- Flexible, helical, spirals
Diplo-
pairs
Staphylo-
Clusters
Strepto-
Chains
The division in staphylo- is in _____ planes
multiple
The division in Strepto- is in ____ planes
a single plane
Organisms that are variable in shape
pleomorphic
Network of long, multinucleate filaments
mycelium
what is the smallest bacteria
Mycoplasma (0.3 micrometers)
The average rode size
1.1-1.5 x 2-6 micrometers
size of E. coli
Epulopiscium fishelsoni is a ___ (size) bacteria
very large - 600 x 80 micrometers
____ cells have a larger surface area to volume ratio
smaller cells
Function of plasma membrane in bacteria
- Selectively permeable barrier
- Mechanical boundary of cell
- Nutrient and waste transport
- location of many metabolic processes (respiration, photosynthesis)
- detection of environmental cues for chemotaxis
What is the function of the Gas Vacuole in bacteria
an inclusion that provides buoyancy for floating in aquatic environments
What is the function of the ribosomes in bacteria
Protein Synthesis
What is the function of inclusions in bacteria
storage of carbon, phosphate, and other substances
What is the function of nucleotide in bacteria
localization of genetic material (DNA)
What is the function of Periplasmic space in bacteria
- in typical Gram-negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient porcessing and uptake
- In typical Gram-positive bacteria it may be smaller or absent
what is the function of the cell wall in bacteria
- protection form osmotic stress
- helps maintain cell shape
What is the function of Capsules and slime layers in bacteria
- Resistance to phagocytosis
- Adherence to surfaces
What is the function of Fimbriae and pili in bacteria
- Attachement to surfaces
- bacterial conjugation and transformation
- Twitching and gliding motility
What is the function of Flagella in bacteria
- Swimming and Swarming motility
What is the function of endospore in bacteria
Survival under harsh environmental conditions
What are the components of the bacterial cell envelope
- Plasma membrane
- Cell wall
- Layers outside the cell wall
do some bacteria have an internal membrane system
yes
is a plasma membrane an absolute requirement for all living organisms
yes
Bacterial membranes lack _______, which is present in Eukaryotic membranes but they do contain _____
sterols (like cholesterol), but do contain Hopanoids
What is the function of Hopanoids in the bacterial membranes
is a sterol-like molecule and stabilizes the membrane
are Hopanoids found in petroleum
yes
Lipid composition of bacterial membranes varies with
environmental conditions (ex. Temperature)
do many bacteria have plasma membrane infoldings
yes
some Archaeal membranes have a ____ structure instead of a bilayer structure
monolayer
Are Archaeal membranes composed of lipids that differ chemically from those of Bacteria and Eukaryotes
Yes
bacterial and eukaryotic lipids contain ___ bonds while Archaeal lipids contain ____ bonds
Ester, Ether
bacterial and Eukaryotic lipids have ___ hydrocarbons attached to glycerol
2
special features of Archaeal lipids
- Ether bonds
- Branched molecules
- Tetraethers (some) (note these make a monolayer)
what are the functions of the Plasma membrane
- Encompasses the cytoplasm
- Selectively permeable Barrier
- Interacts with External environment
- receptors for detection of and response to chemical surroundings
- Transport systems
- Metabolic processes
Substance in which nucleotide, ribosomes, inclusion bodies, plasmids, and cytoskeletal filaments are suspended
Cytoplasm of Bacteria and Archaea
The cytoplasm of bacteria and Archaea lack _____ and are composed largely of ___
- lack organelles bound by unit membranes
- composed largely of water
Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria. What are they
- Actin
- Intermediate filaments
- Microtubules
Are the functions of the cytoskeleton in bacteria similar to in eukaryotes
yes
Function of microtubule homolog FtsZ in Bacteria
Cell division
Microtubule homolog FtsZ is widely observed in
bacteria and archaea
Function of microtubule homolog BtubA/BtubB in Bacteria
Unknown
microtubule homolog BtubA/BtubB is only observed in ____ and thought to be encoded by
Only observed in Prosthecobacter spp
thought to be encoded by eukaryotic tubular genes obtained by horizontal gene transfer
Function of microtubule homolog TubZ in bacteria
Possibly plasmid segregation
Microtubule homolog TubZ is encoded by ____ and observed in
large plasmids and observed in members of the genus Bacillus
Function of actin homolog MamK in bacteria
Positioning magnetosomes
Function of actin homolog MreB/Mbl in bacteria
Helps determine cell shape
may be involved in chromosome segregation
localizes proteins
Function of actin homolog ParM in bacteria
Plasmid Segregation
Actin homolog MamK is observed in
magnetotactic species
Actin homolog MreB/Mbl is observed in
Most rod-shaped bacteria
Actin homolog ParM is ____ encoded
plasmid
function of intermediate filament homolog CreS (Crescentic)
Induces curvature in curved rods
Intermediate filament homolog CreS (crescentin) is observed by
Caulobacter crescentus
What are two unique bacterial cytoskeletal proteins
MinD and ParA
What is the function of the unique bacterial cytoskeletal protein MinD
prevents polymerization of FtsZ at cell poles
What is the function of the unique bacterial cytoskeletal protein ParA
Segregates chromosomes and plasmids
The unique bacterial cytoskeletal protein MinD is observed in
Many rod-shaped bacteria
The unique bacterial cytoskeletal protein ParA is observed in
many species including Vibrio cholerae, C. crescentus, and Thermus themophilus
Microtubule homolog FtsZ is observed in ____ and forms
many bacteria and forms ring during septum formation in cell division
Actin homolog MreB is found in ____ and not ___ and maintains
found in bacilli and not cocci
maintains shape by positioning peptidoglycan synthesis machinery
Intermediate filament homolog CreS is rare, and maintains
curve shape
Inracytoplasmic membranes can be seen as plasma membrane infolding in
- many photosynthetic bacteria
- many bacteria with high respiratory activity
what is Anammoxosome in Plantomycetes
- an Intracytoplasmic Membrane
- An organelle that is the site of anaerobic ammonia oxidation
What are inclusions
granules of organic or inorganic material that are stockpiled by the cell for future use
what are some storage inclusions
- Storage of nutrients, metabolic end products, energy, building blocks
- Glycogen storage
- Carbon Storage
- Poly-beta-hydroxybutyrate (PHB)
- Glycogen
- Phosphate-Polyphosphate granules (Volutin)
- Amino Acids- cyanophycin granules
- Sulfur Granules
Sulphur granules are important in bacteria that don’t use
water
Gas vacuoles are found in
aquatic, photosynthetic bacteria and archaea
Gas Vacuoles are Aggregates of hollow cylindrical structures called
gas vesicles
Function of Gas Vacuoles
Provide buoyancy in gas vesicles
Magnetosomes are found in ____ bacteria
aquatic
what are the function(s) of magnetosomes
magnetite particles (iron) for orientation in Earth’s magnetic field
Cytoskeletal protein ____ helps form magnetosome chain
MamK
Microcompartments in bacteria are not bound by membranes but ________ for specific function
compartmentalized
What are carboxysomes
Microcompartments in CO2 fixing bacteria
- contain the enzyme ribulose-1,5-Bisphosphate carboxylase (Rubisco), enzyme used for CO2 fixation
complex protein/RNA structures that are the sites of protein synthesis
Ribosomes
What is the size of bacterial and archaea ribosomes
70S
What is the size of Eukaryotic ribosomes
80S
What does the S in 80S ribosome stand for
Svedburg unit
What are the Bacterial ribosomal RNA subunits
- 16S small subunit
- 23S and 5S in large subunit
The nucleoid of bacteria is usually not _____ bound
membrane bound (there are a few exceptions)
____ is the location of chromosome and associated proteins in Bacteria
Nucleoid