structure of bacteria Flashcards
cell morphology: 6
coccus, spirochete, rod, budding and appendages bacteria, spirillum, filamentous bacteria
cell size
surface area to volume ratio - faster uptake of nutrients -more cells per given resource -more cells more mutation -drives evolution
difference between phospholipid bilayer in archaea and bacteria
bacteria nd eukarya have ester bond. Archaea have ether bonds
membrane and secreted proteins
proteins secreted int periplasm: protein translated in ribosome from mRNA. SecA added to the end of protein and this allows the protein t be secreted into the periplasm Proteins inserted into membrane: proteins translated and signal recognition particle added to the end and this allows it to be inserted into the membrane
if the translated protein does not have signal sequence attached to it then the protein will
not be secreted or inserted
gram stains distinguish between
gram positive and negative groups
gram positive are
violet
why are gram positive violet
due to presence of thick layer of peptidoglycan in cell walls
gram negative are
red
cell wall made up of
peptidoglycan (murein)
% of cell wall which is murrain in gram positive and negative bacteria
90% in +ve 10% in -ve/
light microscopy
cells can be alive. Diameter of the smallest resolvable object is equal to .51/ numerical aperture. .
what is the magnification and resolution of a light microscope using a 10 ocular lens with a typical 10x objective lens and a light source of 50nm
100 and 1um
cell survive structures
capsule, biofilms, fimbriae and pili, flagella
capsule
polysaccharide or protein or both. Plays a role in pathogenesis and biofilm formation
biofilm
the predominant bacterial phenotype in nature and may form on solid substrates in contact with moisture e.g. teeth, on soft tissue and at liquid air interface
what allows for the control of growth rate and growth yield to be controlled independently
biofilms–> an keep cells in a certain phase for long periods of time, therefore useful for studying enzymes
fimbriae and pili
proteinaceous but can be glycosylated. Plays a role in pathogenesis, biofilms and conjugation–> twitching motility
flagella
multimeric protein complex traversing both inner an outer membrane. Helical shaped.
flagella structure
helical in shape. Anchored by the MS ring in the inner mem. and the L and P ring in the peptidoglycan and outer membrane.
counting bacteria
by either microscopy or by culture
outer membrane
second lipid bilayer in Gram negative bacteria. Not just phospholipids as in cytoplasmic membrane. Large polysaccharide component- lipopolysaccharide
mature biofims
more of the volume is occupied by the loosely organised glycocalyx matrix (75-95%) than by bacterial cells (5-25%). Because the glycocalyx matrix holds a lot of water, abiofilm- covered surface in gelatinous and slippery
secondary colonizers
as well as trapping nutrient molecules,, the glycocalyx net also snares other types of microbial cells through physical restraint nd electrostatic interaction attached to a solid surface
biofilm formation- pic
..
endospore
An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. The primary function of most endospores is to ensure the survival of a bacterium through periods of environmental stress.
