Module 3: Bacterial and archaeal growth and control of microoganisms Flashcards
what is binary fission
- almost all bacterial and archaeal cells reproduce soley on binary fission
- dividing into two simple daughters
what are the steps in binary fission
- cell at early phase of cycle
- a cell prepares for division by enlarging its cell wall, plasma membrane and overall volume DNA replication starts
- the septum begins to grow inward as the chromosome move towards opposite ends of the cell
- the septum is synthesized completely through the cell center creating two chambers
- daughter cells are divided
what is another way bacteria species divid
- budding = bud of a large parent cell
what is a cell cycle
- sequence of events between birth of a new cell through its growth and division
what are the three phases of bacterial cell cycle
- a period of growth after a cell is born
- chromosome replication and partitioning
- cytokinesis, septum and daughter cells are formed
what kind of cell cycle does an archaeal cell have
- ## stage like eukaryotic cells that has G1 S G2 and segrigation phases
what is a PBP
pencicillin binding proteins = targets of the penicillin family and clogg up activation sites
- function is to cut intra strand bonds that join strands of peptidoglycan and allow for insertion of new material
what is cell lysis
- new strands are added but not cross linked together, resulting in loss of walls integritiy
what is a microbial growth curve
- prepare liquid media and incubate until they consume useable nutrients and waste accumulate
- they can plot the gorwth of the population of bacteria vs time of incubation in a linear funtion
what are the 5 phases in the microbiotic curve
- lag phase = initial period of adding the cells into the frsh medium to the exponential phase
- exponential phase = binary fission phase
- stationary phase = cell numbers quit increasing/ they try to adapt to their new environment
- death phase without added nutrients - significant death occurs in the population
- long term stationary phase = new variants arriving in the population
what are the 6 environmental variables
- water
- ph
- temperature
- oxygen concentrate
- pressure
- radiation
what is a halophile
- salt loving organism
- they create compatible solutes within their cytoplasm that do not adversely effect functions of their enzymes but create flow of water into the cell
what is a acidophile
ph between 0-5.5
what is neutrophile
5.5-8
what is a alkalophile
8-11.5
how does temperature effect microoganisms
- cannot regulate internal temperature
they are at the mercy of their external environement
how does oxygen effect microorganisms
- o2 is a reactive gas that can damage dna and proteins if not dealth with properly
how does pressure effect growth
- barotolerant organisms can survive in areas oh very high pressure
- piezophile is an organism with optimal growth under hydrostatic pressure
how does radiation effect growth
- ability to repair damage cause by ionizing radiation or ultraviolet radiation
what are the three ways we control miccrobial contamination
sterilization = killing or removing live spores or cells
disinfectate = killing inhibition or removal or microorganisms that may cause disease
sanitization = reduction of the level of microbs to levels that are considered safe by public health standards
what is antisepsis
destruction or inhibition of microorganisms on living tissue
what are control mechanisms
filtration - retains the microbs behind a barrior
heat - tyndallisation or pasteurization
radiation - ultraviolet radiation or ionization radiation
chemical control
what are the 6 factors that influence effectiveness of getting rid of microbial agents
- population size
- population composition
- concentration of agent
- contact time
- temperature
- local environment
