prokaryotes and their cell structure Flashcards
what are the three domains of life
eukarya
archaea
bacteria
what are the functions of bacterial membrane
separates organelles from the environment
selectively permeable barrier
site of respiration/photosynthesis
conserves energy
what does the cell wall do
provides shape and protects cell
what are the two groups of bacteria when gram staining
gram positive
gram negative
what is a gram positive bacteria
it has a thick cell wall that is made of peptidoyglycan layer which traps the crystal violet in the cytoplasm which isn’t rinsed by the use of ethanol (appears blue/purple)
what is the process of gram staining
stain with crystal violet
add iodine
wash with ethanol
counter stain with safranin
what is a gram negative bacteria
it has a outer membrane and a thin peptidoglycan layer which the crystal violet is easily rinsed by ethanol and then is stained by safranin (apprears red)
peptidoglycan structure
a polymer of sugars
sheet structure crossed linked with peptide bridges
what breaks down a peptidoglycan structure
lysozyme, disrupts the osmotic regulation
what is the purpose of the capsule
proctects from hosts defences
attachment to surfaces
what is the purpose of the fimbriae
recognition and attachment to surfaces
what is the purpose of the pili
required for mating
what is a polar flagellum
flagellum at the end of the cell
what is monotrichous flagellum
one flagellum
what is ampitrichous flagellum
one flagellum at each end of cell
what is lophotrichous flagellum
cluster of flagella at one or both ends
what is peritrichous flagellum
spread over the entire surface of the cell
what is bacterial cytoplasm
gelatinous material inside the cell
what is the nucleotide
a irregular shaped region containing a chromosome/chromosomes
what are plasmids
closed circular DNA molecules that are transferred between bacteria
what are cellular inclusions
granules of organic/inorganic material that are reserves for future use
how are endospores developed
- decides to use one of two polar division sites for septum formation
- replication and formation of axial filament
- the cell separates into two unequal compartments (forespore is smaller)
- mother cell engulfs fore spore
- mother cell chromosome destroyed
- cortex and coat proteins are formed
- maturation from heat and chemical insults
- completing development
- sparangeuim (mother cell) releases mature spore
what is the purpose of endospores
to ensure survival of bacterium through periods of environmental stress
what bacteria make endospores
gram positive bacteria
