Structure of Bacteria Flashcards
Do procaryotes have a nuclear membrane?
No
Do eukaryotes have a nuclear membrane?
Yes
Describe procaryotic DNA?
single, circular structure (may be linear)
Describe eucaryotic DNA?
linear, >1, mtDNA consists of multiple circular chromosomes
How do procaryotes divide?
binary fission (membrane bound, septal ring structure)
How do eucaryotes divide?
mitosis
How do procaryotes pass on genes to daughter cells?
horizontal gene transfer, no sexual reproduction
How do eucaryotes pass on genes to daughter cells?
meiosis
Do procaryotes have introns?
rarely
Describe the prokaryotic cell membrane?
lacks sterols
Describe the eukaryotic cell membrane?
contains sterols
Describe the location of the respiratory system in procaryotes. ETC/ATP synthesis
plasma membrane
Describe the location of the respiratory system in eucaryotes. ETC/ATP synthesis
mitochondria
Describe the presence of sub cellular organelle in procaryotes.
No lipid bound organelle with NA, most absent sub cellular organelle without NA
Describe the presence of sub cellular organelle in eucaryotes.
lipid bound membranes with NA (mitochondria, chloroplasts) and without NA (golgi, ER, etc)
Describe the presence of protein bound microcompartments in procaryotes.
present without NA
Describe the presence of protein bound microcompartments in eucaryotes.
absent
Describe procaryotic ribosomes.
70S (50S + 30S)
Describe eucaryotic ribosomes.
80S (60S + 40S), except 70S in mitochondria
Describe the cytoskeleton components in procaryotes.
present - homologs of actin, tubulin, IFs
Describe the cytoskeleton components in procaryotes.
actin, myosin, tubulin, IFs
Describe the presence of endospores in procaryotes.
present - resists heat, drying, chemicals
Describe the presence of endospores in eucaryotes.
absent
Describe the presence of cell walls in procaryotes.
present - most possess peptidoglycan
Describe the presence of cell walls in eucaryotes.
only plants, fungi possess a polysaccharid cell wall
Describe flagella in procaryotes.
present - submicroscopic single repeating peptide
Describe flagella in eucaryotes.
present - microscopic 9+2 microtubule arrangement
Describe surface motility in procaryotes.
multiple types - pili, flagella, exopolysaccharide, cytoskeleton
Describe surface motility in eucaryotes.
amoeboid
Describe the typical size of procaryotes.
< 2 um
Describe the typical size of eucaryotes.
2 - 100 um
Positive stain and examples
stain that colors cells, not medium… gram stain
Negative stain and examples
stains medium not cells… india stain
Gram positive
extensive peptidoglycan layer retains crystal violet-iodine complex after destaining (blue/purple)
Gram negative
then peptidoglycan layer does not retain crystal violet-iodine complex after destaining (pink, red)
Describe the steps on Gram staining
- crystal violet - positive stain
- iodine - fixative that forms complex with the violet
- alcohol - destain
- safranin - counter stain - positive stain
Alcohol destain during gram staining in excess? insufficient?
All cells are destained and appear negative. All cells retain crystal complex and appear positive.
Gram variable in a pure culture
If gram positive bacteria has structural damage to its peptidoglycan layer (dead/damaged) it may appear negative in some cells and positive in others
Bi-polar staining
safety pin appearance of a gram-negative rod
Modified Gram staining
use of carbol-fuchsin counterstain instead of safranin in lightly staining gram-negative bacteria
What can a gram stain, size, shape, and cell arrangement tell you?
Cannot identify bacteria, but can direct the antimicrobial therapy and aid in identifying the microbe
Acid-fast staining
used to stain bacteria that are not gram-positive or negative due to their complex wall structure
What genera of bacteria must be stained using acid-fast staining?
Mycobacterium and Nocardia
What are the genera of Gram-positive bacteria?
Actinomyces, Bacillus, Bifidobacterium, Clostridium, Cornyebacterium (Propionibacterium and other diptheroids), enterococcus, Gardnerella, Lactobecillus, Listeria, Mobiluncus, Peptostreptococcus, Staphylococcus, Streptococcus
Medically important gram-positive cocci
streptococcus, staphylococcus, enterococcus
Medically important lancet-shaped diplococci
streptococcus pneumoniae
Genera of bacterial endospore-formers
clostridium, bacillus
genera of medically important gram negative “kidney bean” shaped diplococci
neisseria, veillonella, moraxella
genera of gram negative comma (vibrio) shaped bacteria
vibrio, helicobacter, campylobacter
genera of acid-fast positive (pink) bacteria
mycobacteria, nocardia
What’s another name for peptidoglycan?
murein sacculus
Cell shape is determined by
murein sacculus and cytoskeleton
Genera of gram negative diplococcus
Neisseria, moraxella, veillonella (2 kidney beans side-by-side)
Genera of gram positive diplococcus
streptococcus pneumoniae (2 footballs end-to-end)
Genera of gram positive chains
Streptococcus
Genera of gram positive clusters
staphylococcus
Genera of gram negative coccobacilli (short rods)
Bordetelle, brucella, francisella tularemia, haemophilus spp, yersinia spp
Short thin needle like rods are called
fusiforms
Genera of gram positive long, thick rods
bacillus, clostridium
Genera of gram positive short, thick rods
listeria
Genera of gram positive clubbed shaped rods
corynebacterium spp, propionibacterium acnes
Genera of gram positive thin, branching filamentous rods with clubbed endings
actinomyces, nocardia
Genera of gram negative curved.comma-shaped rod
campylobacter, helicobacter, vibrio
Genera of gram positive curved.comma-shaped rod
mobiluncus spp
Spirochetes
borrelia, leptospira, treponema
Pleomorphic cell shape describes
a variation in size and shape