survey of prokaryotic cells and microorganism Flashcards
all living things are made of cells that share some common characteristics
basic shape
internal content
DNA chromosomes
two basic cell types
eukaryotic and prokaryotic
eukaryotic cells
animals, plants, fungi and protists
contain membrane-bound organelle that compartmentalize the cytoplasm and preform specific functions
prokaryotic cells
bacteria and archaea
No nucleus or other membrane-bound organelles
characteristics of life
reproduction and heredity
growth and development
metabolism
movement and/or irritability
cell support
transport of nutrients and waste
external structures
appendages 2 major groups of appendages
motility and attachment
external structures
glycocalyx- surface coating
flagella 3 parts in a prokaryotic cell
filament
hook
base body
filament
long, thin, helical structure composed of protein flagellin.
hook
curved sheath
base body
stack of rings firmly anchored in a cell wall
flagella rotates
360 functions in motility of cell through environment Run and Tumble movement
flagellar arrangements
monotrichous
lophotrichous
amphitichous
peritrichous
monotrichous
single flagellum at one end
lophotrichous
small branches emerging from the same site
amphitrichous
flagella at both ends of cell
peritrichous
flagella dispersed over surface of cell
chemical stimuli
chemotaxis; positive and negative
light stimuli
phototaxis
counterclockwise
results in smooth linear direction- run
clockwise
tumbles
internal flagella
enclosed in the space between the outer sheath and the cell wall peptidoglycan
produce cellular motility by contracting and impairing twisitng or flexing motion
fimbriae
fine, proteinaceous, hairlike bristles emerging from the cell surface function in adhesion to other cells and surfaces
pili
rigid tubular structure made of pili protein found only in gram- negative cells function to join bacterial cells from partial DNA transfer called conjugation
glycocalyx
coating of molecules external to the cell wall made of sugars and/or proteins
glycocalyx two types
slime layer loosely organized and attached
capsule highly organized tightly attached
functions of glycocalyx
protect cells from dehydration and nutrient loss.
attachment formation of biofilms
the cell envelop
external covering outside the cytoplasm
composed of 2 basic layers
cell wall and cell membrane
maintains cell integrity
two different groups of bacteria demonstrated by Gram stain
gram- positive
gram-negative
gram-positive bacteria
thick cell wall composed primarily of peptidoglycan
gram-negative bacteria
outer cell membrane thin peptidoglycan layer and cell membrane
gram-positive cell wall
20 to 80 nm thick peptidoglycan includes teichoic and lipoteichoic
some cells have a periplasmic space
gram- negative cell wall
inner and outer membranes and periplasmic space between them contains a thin peptidoglycan layer
the gram stain
differential stain that distinguishes cells with a gram-positive cell wall from those with a gram-negative cell wall
gram-positive
retain crystal violet and stain purple
gram-negative
lose crystal violet and stain red from safranin counterstain
some bacterial groups lack typical cell wall structures that is
mycobacterium and nocardia
cell membrane structure
phospholipid bilayer embedded proteins - fluid mosaic model
cell membrane functions
providing site for energy reactions nutrient processing and synthesis
passage of nutrients into the cell and discharge of wastes
chromosomes
contain all genetic information required for a cell
plasmids
used in genetic engineering
inclusions and granules
intracellular storage bodies
cell cytoplasm
serves as solvent for materials used in a cell function
ribosomes
site of protein synthesis found in a cells
cytoskeleton
skeleton of the cell hold cell shape from the inside internal network of proteins polymers
endospores
when exposed to adverse environment conditions capable of high resistance and very long term survival
sporulation
formation of endospores
germination
return to vegetative growth
at what time will steam destroy endospores
pressurized steam at 120 C for 20 - 30 minutes will destroy
coccus
spherical
bacillus
rod
spirillum
helical, comma, twisted rod
pleomorphism
variations in cell shape and size within a single species
diplococci
in pairs
tetrads
gropus of 4
steps of the gram stain
crystal violet
gram siodine
alcohol (mordants)
alcohol (decolorized)
safranin (red dye counterstain)
Bergey’s manual of determinative bacteriology
five volume resource covering all known prokaryotes two domains: archaea and bacteria
domain archaea
adapted to extreme habitats and modes of nutrition
domain bacteria
everyday bacteria
species
a collection of bacteria cells which share an overall similar pattern of traits in contrast to other bacteria whose pattern differs significantly
stain or variety
a culture derived from a single parent that differs in structure or metabolism from other cultures of that species
prokaryotes with unusual characteristics
free-living nonpathogenic bacteria
photosynthetic bacteria
use photosynthesis energy directly from the sun
rickettsias
very thin gram-positive bacteria most are pathogens obligate intracellular pathogens cannot survive or multiply outside of a host cell
chlamydias
tiny
obligate intracellular parasites not transmitted by arthropods
archaea
constitute third Domain Archaea exist in extreme environments
archaea
adapted to heat, salt, acid pH, pressure and atmosphere
