Basic Bacteriology Flashcards
what is a diplococci?
a bacterium that occurs as pairs of cocci
shape of streptococci
live in pairs or chains of varying length
shape of tetrad cocci
four balls
shape of sarcinae
cube of four balls
shape of saphylococci
a cluster of balls
types of spiral bacteria
- Vibrio
- most common cause of food poisoning in Japan - Spirillum
-Ex: rhodospirillum - Spirochete
- capable of easy infection. Ex: lime disease
what type of bacteria tend to live in hypotonic enviroments?
star-shaped and rectangular prokaryotes
how big is a small subunit
30s
how big is a small subunit
30s
how big is a large subunit
50s
how large is a complete ribosome
70s
which structures are found in all bacteria
- Cytoplasm
- 70S Ribosomes
- Plasma membrane
- Nucleoid containing DNA
- Plasma membrane
what is the purpose of the capsule in a prokaryotic cell?
to protect against phagosynthesis
what is the purpose of the plasma membrane in prokaryotes
- make cell wall
- transport things in and out of the cell
what is the purpose of the inclusions
important in adjusting the environment of the cell
purpose of plasmid
- extral chromosomal dna
- non-essential coding of characteristics
- tend to be lost in the absence of selective pressure Ex: antibiotics
purpose of pilli
- involved with gene transfer and attachment to surfaces Ex: teeth
study slide
20
definition of virulence
extent of pathogenity
what is Peritrichous flagella
- having flagella uniformly distributed over the body
what is Monotrichous and polar flagella
one flagellum at one pole
Lophotrichous and polar flagella
multiple flagella located at the same spot on the bacteria’s surfaces
what is Amphitrichous and polar flagella
a single flagellum on each of two opposite ends
what is the motor that drives flagella driven by
a proton gradient
difference between a gram-negative and gram-positive flagella motor
the gram-negative bacteria have an outer membrane whereas the positive do not
what is the motor of the flagella held by
peptidoglycan
direction of clockwise flagella results in…
tumble
direction of counter-clockwise flagella results in…
run
Random movement toward an attractant causes a drop in
CheY-P levels, which allows CCW rotation and swimming.
what initiates a series of events lowering the CheY-P levels
Methyl-accepting chemotaxis proteins (MCPs)
reversable methylation of MCPs causes
desensitizes MCPs
demethylation of MCPs results in
sensitizes MCPs
definition of chemotaxis
refers to the migration of cells toward attractant chemicals or away from repellents.
driven by:
- methylation
- demethylation
- phospholation
biased random walk
enables bacteria to search for food and flee from harm
what are axial filaments
bundles of flagella which wrap around the cell body between the cell wall and the outer membrane
what is a biofilm
an assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix
Ex: plaque on teeth
what happens to the flagella after biofilm is formed
the bacteria stop using them
why is cystic fibrosis chronic
because the formation of biofiliments are highly resistant to antibiotics
what is quorum sensing
a bacterial cell–cell communication process
what is a characteristic of encapsulated bacteria
shiny
characteristics of gram positive bacteria
gram reaction: blue stain
peptidoglycan layer: thick
teichoric acids: present
periplamic space: absent
outer membrane: absent
LPS content: none
lipid and lipoprotein content: low
flagellar structure: two rings in basal body
characteristics of gram negative bacteria
gram reaction: pink or red
peptidoglycan layer: thin
teichoric acids: absent
periplamic space: present
outer membrane: present
LPS content: high
lipid and lipoprotein content: high
flagellar structure: four rings in basal body
how do we test water for endotoxins
using limilus
what part of a bacterial is an endotoxin
the Lipopolysaccharide
what part of the bacteria does penicillin attack
the teichoic acid structures
what does lysosyme do
breaks down peptidoglycan
penicillin inhibits the formation of what enzyme?
transpepidase
penicillin inhibits the formation of gram-positive bacteria by
inhibiting peptidoglycan production
gram positive bacteria lose s layer when
they are transferred from culture to culture
function of porin in gran negative bacteria
The porins act as molecular filters for hydrophilic compounds
what is a protoplast
bacterial cell without cell wall
what is a sheroplast
a bacterium or plant cell bound by its plasma membrane, the cell wall being deficient or lacking and the whole having a spherical form.
where is the electron transport system located?
in the plasma membrane
Membranes have approximately equal parts of
phospholipids and proteins.
what is the structure of phospholipids
glycerol with ester links to two fatty acids and a phosphoryl head group
what are the two layers of phospholipids in the bilayer called?
leaflets
The structure that defines the existence of a cell is the
cell membrane.
what is the function of a hopanoid
intercalate into phospholipid bilayers and modulate the fluidity of membranes by interacting with their complex lipid components.
calcium heat shock is used to
used to introduce foreign DNA into a host cell. The concept of the technique is to render cells competent using CaCl2 to allow for introduction of plasmid.
what are zones of adhesions
area of a lipid bilayer where inner and outer leaflets join
what is Simple Diffusion
Simple diffusion is an unassisted type of diffusion in which a particle moves from higher to a lower concentration.
what is Facilitated Diffusion
the transport of substances across a biological membrane through a concentration gradient by means of a carrier molecule(noinputofenergy)
aquaporins
transmembrane diffusion of water
what is passive transport
molecules move along their concentration gradient does not require energy
what is Active transport
molecules move against their concentration gradient also requires energy
Group translocation is
process where a molecule crossing the cell membrane not only gets transported but also gets transformed in itself
The phosphotransferase system (PTS) present in all bacteria. is an example of group translocation. what is its function?
- It uses energy from phosphoenolpyruvate (PEP) to attach a phosphate to specific sugars.
- The system has a modular design that accommodates different substrates.
what is a storage granule
- Glycogen, PHB, and
PHA, for energy - Sulfur, for oxidation
what are magnetosomes
- Membrane-embedded crystals of magnetite, Fe3O4
- Orient the swimming of magnetotactic bacteria
what are magnetosomes
The magnetosome is defined as an intracellular organelle consisting of a single-magnetic-domain crystal of a magnetic iron mineral enveloped by a lipid-bilayer membrane that contains proteins that are unique to it.
the process of endospore formation is called
sporulation
six steps of sporulation
- Spore septum begins to isolate newly replicated DNA and a small portion of cytoplasm.
- Plasma membrane starts to surround DNA, cytoplasm, and membrane isolated in step 1.
- Spore septum surrounds isolated portion, forming forespore.
- Peptidoglycan
layer forms between membranes. - Spore coat forms.
- Endospore is freed from cell.
function of endospore
Endospores ensure the survival of bacteria in adverse environmental conditions
what is sigma-F
a protein that enhances transcription
what are the proteins that coat dna in endospores
small acid soluble proteins (SASP)
endospores exist in what kind of environment
Endospores exist in a cryptobiotic state
what are bacteriocins
toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s)
what is the exosporium
The exosporium is the outer surface layer of mature spores
ER is continuous with..
membrane envelope
what is the purpose of pores on nuclear membrane
transports things in and out of nucleus
FtsZ = forms a
“Z-ring” in
spherical cells
MreB = forms a
coil inside rod-shaped cells
CreS “crescentin” = forms a
polymer along the inner side of crescent-shaped bacteria
purpose of smooth er
detoxification and lipid synthesis
what is the golgi complex
The Golgi complex prepares proteins and lipid (fat) molecules for use in other places inside and outside the cell
what does the mitochondria have
- circular dna and 70s ribosomes
- the dna is maternally inherited
The Theory of Endosymbiosis
States that some organelles evolved from a symbiosis in which one cell of a prokaryotic species was engulfed by and lived inside of a cell of another species of prokaryote
what is the plasma membrane
The plasma membrane, also called the cell membrane, is the membrane found in all cells that separates the interior of the cell from the outside environment
what is the endoplasmic reticulum is involved in what synthesis
a network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis
what is a lysosome
A lysosome is a membrane-bound cell organelle that contains digestive enzymes
what is a peroxisome
A peroxisome (IPA: [pɛɜˈɹɒksɪˌsoʊm]) is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells.
which genus makes more capsules given sugar
genus leubonostoc
what are the characteristics of Staphylococcus
- Facultative anaerobes
- Cocci in clusters
- S. aureus
Streptococcus characteristics
- Aerotolerants
- Cocci in chains
- S. pneumoniae
- S. pyogenes
