Day 3 prokaryotic cell structure and function Flashcards
How do bacteria and archaea differ( 5 ways)
in structure chemical composition nutritional requirements biochemical activities source of energy
What is the size of bacteria
range from 0.2 to 2.9 um in diameter
Bacteria shape: Coccus
Round
Bacteria shape: bacillus
rod
bacterial shape:Vibrio
curved rod
bacterial shape: coccobacillus
short rod
bacterial shape: spirillum
spiral
Bacteria shape: spirochete
long loose helical spiral
What are the 2 usual shape of bacteria
stella ( star shaped)
haloguadratum ( rectangular)
Cell Arrangement: coccus
single coccus
Cell arrangement: diplococcus
pair of cocci
Cell arrangement: tetrad
group of 4 cell arranged in a square
Cell arrangement: streptococcus
chain of cocci
Cell arrangement: staphylococcus
cluster of cocci
cell arrangement: bacillus
single rod
cell arrangement: streptobacillus
chain of rods
define monomorphic
having a single form, structural pattern, or genotype
define pleomorphic
occurring in various distinct forms
Describe the outermost structure Glycocalyx and the 2 forms in exists in and its importance
- viscous and gelatinous( made of polysaccharide and/or polypeptides
- two types: capsule ( firmly attached) or slime layer ( loose)
- strengthens the cell surface, helps attach cells together, and contribute to cell-cell recognition
- can contribute to virulence, protects against phaocytosis, and attachment
Describe the outermost structure flagella is
filamentous structure
propel bacteria
made of protein flagellin
What are the 3 parts of the flagella
filament
hook
basal body to anchor
Define atrichous
bacteria that lack flagella
Define monotrichous and polar
having a single flagellum
define lophotrichous and polar
having 2 or more flagella at 1 end of a cell
define amphitrichous and polar
having flagella at both ends of a cell
Define peritrichous
having flagella uniformly distributed over the body
if the flagella roates clockwise its called
run
if the flagella roates anti-clockwise
tumbles
Define taxis
movement towards or away from a stimulus
Define phototaxis
movement in response to the presense of light
Define chemotaxis
movement in response to the presence of a chemical
Define attractant
movement toward a higher concentration of a stimulating substance
Define repellent
movement away
Define H antigen
identifying variations
ex/ e.coli 0157:h7
Define axial filaments ( endoflagella)
found in spirochetes
spiral around the cell
move like a corkscrew
Define fimbriae
fimbria allow for attachment/ bind to specific receptor structure
long filamentous polymeric protein structures located at the surface
Define pilus ( pl. pili)
hair like appendage found on the surface of many bacteria and archaea
- motility
- can be used for conjugation
Describe the cell wall
complex, semi-rigid structure
protects cell membrane
prevents osmotic lysis
What is the composition of the cell wall
made of peptidoglycan ( only in bacteria) that contributes to pathogenicity
What are the 2 peptidoglycan and what is the link
N-acetylglucosamine (NAG)
N-acetyl muramic acid (NAM)
BETA 1,4 LINK
linked by polypeptides
Describe gram-positive cell wall
think peptidoglycan
teicholic acids
describe gram negative cell wall
thin peptidoglycan
outer membrane
lipopolysaccharide
Describe the outer membrane of gram negative
made of lipopolysaccharides, lipoproteins, phospholipids
periplasm present b/t the cell membrane and the peptidoglycan
Describe lipopolysaccharides
in gram negative bacteria
major component of the outer membrane
What are the 3 parts of the lipopolysaccharide
Lipid A: endotoxin
Core polysaccharide: provide support
O polysaccharide: function as antigen
What are porins in gram-negative cell walls
act like pores
permit the passage of molecules such as nucleotides,disaccharides, peptides,amino acids,vitmain B12,and iron
hat color does gram positive bacteria appear
purple or blue
What color do gram-negative bacteria appear
pink
What is the gram stain procedure
1) application of crystal violet ( purple dye)
2) application of iodine ( mordant)
3) alcohol wash ( decolorization)
4) application of safranin ( counterstain)
How are gram positive stained purple
crystal violet iodine crystal form in cell
alcohol dehydrates the peptidoglycan
CV-I crystals do not leave
How are gram-negative stain pink
alcohol dissolves outer membrane and leaves holes in peptidoglycan
cv-i washes out
safranin adds to stain cells
What is a atypical cell wall and how are they stained
acid fast cell walls
has waxy lipid ( mycolic acid) bound to peptidoglycan
ex. mycobacterium and nocardia
stained with carbolfuchsin
What are 2 ways damage can be done to the cell wall
1) lysozyme hydrolyzes bonds in peptidoglycan
2) penicillin inhibits peptide bridges in peptidoglycan
What is the plasma ( cytoplasmic) membrane made of?
composed og phospgolipids ( bilayer) and proteins
contain glycoproteins and glycolipids
selective permeability
What is the fluid mosiac model
mosaic of components including a phospholipids, cholesterol, proteins, and carbohydrates that give the membrane a fluid character
What is sterol
membrane strengthening agent
eukaryotic membrane
prevents movement of phosolipids
What are hopanoids
membrane strengthing agents
many bacteria has it
similar to steriods
Describe the phospholipids of bacteria and eukaryotes
ester linkages and strain chained
Describe the phospholipids in archaea
ether linkages
branched chained
What type of plasma membrane do archaels have
lipid monolayers
What are the 2 pigments of photosynthetic pigments
chromatophores or thylakoids
What are the 3 principles of osmosis
isotonic
hypotonic: water moves into cell and gets bigger
hypertonic: water moves out of cell
What is required in active transport
transporter protein and ATP
What is group translocation
in prokaryotes
require a transporter protein and PEP( phosphoenol pyruvic acid)
Define cytoplasm
80% water,proteins,carbohydrates,lipids,ions
structures in the cytoplasm are nucleoid,ribosomes,inclusions
define the nucleoid
bacterial chromosome
circular double stranded haploid
plasmids-extrachromosomal DNA
DEFINE RIBOSOMES
sites of protein synthesis
protein and rRNA
What is the ribosome of prokaryotic cells
70s
What is the ribosome of eukaryotic cells
80s
What are all the different types of inclusions
metachromatic granules ( inorganic phosphate)
polysaccgarides granules ( glycogen or starch)
lipid inclusions ( polyhydroxybutyrate-PHB)
magnetosomes ( iron oxides)
sulfur granules
carboxysomes( carboxylase enzymes)
gas vacuoles
When are endospores produced
1) essential nutrients are depleted
2) large amount of waste is collected
usually in gram positive bacteria
What are endospores
highly durable,dehydrated cells with thick walls
survive extreme environmental conditions
What are 2 examples of bacteria that create endospores
bacillus anthracis
clostridium tetani
Define sporulation or sporogenesis
endospore formation
Define germination
return to vegetative state
What are characteristics of vegatative cells
1) sensitive to extreme temperatures and radiation
2) gram positive
3) normal water content and enzymatic activity
4) capable of active growth and metabolism
What are characteristics of endospores
1) resistant to extreme tempertures and radiation
2) do not absorb gram stain, only special endospores stain
3) dehydrated; no metabolic activity
4) dormant; no growth or metabolic activity
What are the 3 forms of bacterial endospores
terminal spores
subterminal spores
central spores
