Chapter 4: Prokaryotic cells - Bacteria Flashcards
when did prokaryotic cells emerge?
3.5 billion years ago
pilus characteristics
- long filament used for genetic recombination; conjugation
- contains ~4,000 genes
- provides genetic variety for bacteria
- generally responsible for antibiotic resistance
- hollow part transfers piece of DNA from one bacterium to the other
plasmid characteristics
- small independent pieces of DNA
- contain resistant genes
- used in genetic engineering
what is fimbriae and its purpose?
short filaments around the cell that allow cell to attach to surfaces
what is a bacteria’s cell wall made out of?
peptidoglycan; a carbohydrate linked to a protein
what is mycoplasma and example?
a bacteria that lacks a cell wall, making it resistant to antibiotics
ex. mycoplasma pneumonia cannot be cured with penicillin like most infections
function of flagella
filament that allows cell to move
what does atrichous mean?
bacteria with no flagella
what does monotrichous mean?
bacteria with one flagella
what does amphitrichous mean?
two flagella; one on opposite sides of the cell
what does lophotrichous mean?
multiple flagella on one side of cell
what does peritrichous mean?
flagella all around the perimeter of the cell
what do antibiotics stop?
the synthesis of peptidoglycan (cell wall)
what is conjugation, and what occurs?
genetic recombination; where resistance plasmids are shared between bacteria
- mediated by the action of the pilus
about how many ribosomes are present in a bacterial cell?
20,000
list capsule characteristics
- only in some bacteria
- an extra layer above the cell wall
- made of carbohydrate
- hard to swallow by macrophages
endospores characteristics
- some bacteria can produce endospores
- bacteria transform themselves into hard structures that make them resistant to temperatures and chemicals
- contain a lot of calcium and dipicolinic acid
axial filaments
flagella inside the cell
- allows cells to move and jerk like a caterpillar
ex. syphillis
all filaments are made up of ______
protein
what is the cell envelope of a bacteria composed of?
- cell membrane
- cell wall
- glycocalyx
glycocalyx characteristics
- present in some bacteria
- contains slime layer and capsule
capsule characteristics and benefits
- an extra hard layer of a carbohydrate
- thick and gummy and difficult to remove
- stuck to the surface
- a combination of polysaccharides and proteins
- protects from phagocytes and macrophages
- makes it difficult for antibiotics to penetrate
slime layer characteristics and functions
- biofilm
- an extra soft layer of a carbohydrate
- loose structure that is sticky
- serves as a protection from dehydration or losing nutrients
- allows bacteria to be sticky
gram-negative characteristics
- thin cell wall
- stains red/pink
- extensive periplasmic space
- less permeable to molecules
- very thin layer of peptidoglycan with two cell membranes
- has lipopolysaccharide (LPS); are endotoxins that have the ability to cause infection
gram-positive characteristics
- thick cell wall
- stains blue/purple
- narrow periplasmic space
- more permeable to molecules
why are some gram-positive bacteria difficult to stain
they may have an extra layer of mycolic acid (lipid)
what is bacillus anthracis?
a spore-producing bacteria that produces anthrax and is used by bioterrorists
clostridium
- bacteria from the soil
- anaerobic
- spore producing
- can cause botulinum (food poisoning)
- can cause tetanus
listeria monocytogenes
- causes listeria
what is the most common cause of listeria?
unpasteurized dairy products
what does Propionibacterium produce?
- acne
- propionic acid
uses of Propionibacterium
- cheese industry; propionic acid give swizz cheese its flavor
streptococcus variants
- group A strep: flesh-eating bacteria
- strep throat: bacteria that affect the throat
what does Enterococcus cause
diarrhea
Staphylococcus characteristics
- food contaminant
- can affect skin, bones, brain, etc.
- mostly found in hospitals
- produces nosocomial infections
what are nosocomial infections
infections acquired in hospitals
Gram-positive bacteria genera examples
- Bacillus anthrasis
- Clostridium
- Listeria monocytogenes
- Propionibacterium
- Streptococcus
- Enterococcus
- Staphylococcus
gram-negative bacteria genera examples
- Bacteroides
- Pseudomonas
- Escherichia Coli
- Salmonella
- Shigella
- Yersinia
- Syphilis
- Vibrio
- Campylobacter
- Helicobacter
- chlamydia
- Neisseria
what is lipopolysaccharide (LPS) and what does it do
- an endotoxin present in gram-negative bacteria
- molecules secreted that allow for the cause of infection
Bacteroides
the most abundant bacteria in the human intestine; Bacteroides fragilis
Pseudomonas
- found in the soil
- can metabolize any type of compound (even soap)
What gram negative bacteria can be useful in the case of an oil spill and why?
pseudomonas because it can eat anything
Escherichia Coli
- found in intestines and causes diarrhea
salmonella
- found in intestines
- food contaminant
- can kill people
shigella
- has a Shiga toxin that can cause severe intestinal disease
yersinia
- yersinia pestis: used to kill many and was spread through fleas
- would kill 80% of population when reached a town
- caused what is known as the Black Plague
- now a simple genus that can be easily controlled with antibiotics
neisseria
- produces STDs such as gonorrhea
gonorrhea symptoms
- produces pus in the urethra and can spread to fallopian tubes
- men can become infertile as well
syphilis
- spiral bacteria
- has internal flagella
- causes STD syphillis
vibrio
- vibrio cholera disease
»» causes watery diarrhea, causing dehydration - Vibrio vulnificus
»» can contaminate oysters
Campylobacter
- involved in food contamination
helicobacter
H. pylori: grows in the stomach
- causes stomach ulcers
- can be controlled with antibiotics
chlamydia
- causes STD
- very small bacteria
which are the only bacteria that grow intracellularly like viruses and are considered intracellular parasites?
chlamydia and rickettsia
which gram negative bacteria is difficult to stain?
- rickettsia
- chlamydia
- legionella
- leptospira
- coxiella
- treponema
- bartonella
mycoplasma pneumonia characteristics
- has no cell wall
- pleomorphic
- antibiotics will not work because there is no cell wall
cell membrane characteristics
- made of phospholipids
- substances can only pass with the use of protein channels
what is the cytoplasm?
- matrix that supports all structures found in a cell
ribosomes is a place for _______
protein synthesis
chromosomes is another name for _______
DNA
DNA of bacteria characteristics
- very compacted
- circular
- 1000x longer than actual bacteria
- ~ 4,000 genes
examples of bacteria that produce endospores
clostridium and bacillus
why does a bacteria turn itself to an endospore and what happens when they do?
when they feel threatened by the environment and they become inactive until the environment is suitable
how do spores of bacillus anthrasis become toxic?
Once people inhale them, they enter the lungs, which is a suitable environment. They revert back to bacteria and produce the disease anthrax.
what shape is coccus bacteria?
round
what shape is bacillus?
rods
what shape is vibrio
curved
what shape is spirillum
spiral
what shape is spirochete
corkscrew; very spiraled
pleomorphic
bacteria that can take up any shape because of the lack of cell wall
diplococci definition and example
two cocci joined together
ex. Neisseria; bacteria causing gonorrhea
tetrads definition and example
cocci in groups of four
ex. micrococcus; bacteria on the skin
irregular clusters definition and example
cocci resembling grapes
ex. staphylococcus; resistant to many antibiotics
streptococci
chain of cocci
sarcina
- groups of cocci in multiples of 8
diplobacilli
two rods of bacilli
streptobacilli
chain of rods
what are the most common shapes of bacilli
single, diplo, and strepto
what taxonomic system is used for prokaryote classification
Bergey’s Manual of Determinative Bacteriology
what are the volumes found in Bergey’s Manual of Determinative Bacteriology
I. Domain Bacteria/Archae
II. Proteobacteria (gram-negative)
III. Low G+C bases; gram positive bacteria
IV. High G+C bases; gram positive bacteria
V. Gram negative
Bergey’s Manual of Determinative Bacteriology classification is based on:
the cell wall in detail
what is medical classification based on?
the structure of the cell wall
In medical classification, a gram-positive/ thick cell wall is considered:
firmicutes
- they are very FIRM because of thick cell wall
In medical classification, a gram-negative/ thin cell wall/ pink stain is considered:
gracilicutes
In medical classification, a bacteria with no cell wall is considered:
tenericutes
In medical classification, a bacteria with an unusual composition of cell wall is considered:
mendosicutes
what disease does rickettsia cause and how is it transmitted?
Rocky Mountain Fever; transmitted by ticks, lice, and fleas
what is a unique feature bacterias rickettsia and chlamydia share?
they have no metabolism, so they cannot live outside of a host
what diseases does chlamydia cause and how are they transmitted?
Chlamydiosis (STD); transmitted through sexual contact
Trachoma: disease of the eyes
photosynthetic bacteria definiton
- bacteria that have different pigments similar to chlorophyll that allow them to perform photosynthesis
- considered autotrophs
cyanobacteria characteristics
- aka blue-green bacteria
- gram negative
- photosynthetic
where can cyanobacteria be found?
in aquatic environments
what allows cyanobacteria to float?
gas inclusions
why are cyanobacteria considered pests?
they compete for oxygen with fish, depleting the fish’s nutrients
green and purple sulfur bacteria characteristics
- found in sulfur springs, deep in lakes, swamps, fresh water
- bacteriochlorophyll: pigments allow them to photosynthesize
- has structures that can store sulfur
Archaea compared to bacteria
- exceptional structure of physiology
- chemically different
TRUE OR FALSE: Archaea are more closely related to eukaryotes than bacteria.
TRUE
What features in archaea support the idea that they are more closely related to eukaryotes than bacteria?
- the introns and histones found in its DNA (bacteria do not have these)
- 80S ribosome (bacteria has 70S ribosomes)
- mRNA has a cap and tail (5’ - 3’)
what are introns?
“junk DNA”
- DNA that does not code for anything
methanogens definiton
- archaea that produce methane
- contribute to greenhouse effect
halophiles definition and example of where to find them
- archaea that can grow in an environment up to 36% NaCl
ex. the Dead Sea
thermophiles definition and example of environment
- archaea that can withstand temperatures up to 120 C
- live near volcanoes
what gas is able to kill all endospores, but area needs to be cleared as it is a carcinogen?
ethylene oxide
