acidophiles grow best at what pH range?
pH of 5 or less (acidic)
alkaliphile grow best at what pH range?
pH of 9 or more (alkaline)
human pathogens grow best in what pH range?
what is another name for pH?
hydrogen ion concentration
what does light do to bacteria?
all light is harmful to bacteria
what specific type of light is the most harmful to bacteria?
UV Ultraviolet light- as UV light passes through the cell it alters the structure of the DNA-causing mutations to occur that are lethal to the cell
how do bacteria typically reproduce?
single transverse division-an asexual form of reproduction, in order for this to occur, individual cells must grow in size, as a result of the division, there are two cells left that are of the original size
is binary fission sexual or asexual?
*cell increases in size
*The mesosomes pull apart the copies
*a new cell all and cell membrance are formed to form 2 new daughter cells
doubling time/bacterial generation time
it is the time it takes a bacteria to do one binary fission
starting: from having just divided
ending: at the point of completing the next division
*2 organisims in which one organism is harmed by the presence of the other
*often due to the production of a substance by one bacteria that inhibits growth or kills the other
"to eat at the same table"
2 organisms growing together but there is only benefit to one organism while there is no effect on the other , 2nd organism is neither benefited or harmed
2 grow well together and can't survive without the other
2 grow well together but can survive on their own, do better together but can survive on their own
2 organsism in which one is the host and the other is a parasite, parasite gains nutrition, protection, and livelihood from the host-usually at the expense of the host
organic catalyst, cause the physiological chemical reactions that occur in living cells o be started or to be carried to completion, protein by nature, always end in "ase"
what causes the physiological chemical reactions that occur in living cells to be started or caused to completion?
substance upon which an enzyme will act, they are the organic compounds present in the cell, every organic compound has a specific type of enzyme that will react with it, every enzyme is very specifics as to what substrate it will react with
common enzymes and the substrates upon which they act:
lipase-fats and lipids
nuclease-dna and rna
what are enzymes made up of?
they are protein by nature
selective flow of a diffusible component through a semi-permeable membrane, passage of a solvent from an area of lesser concentration to greater concentration when the two are separated by a semi-permeable membrane, tries to even the solutions out since the solute cannot move across the membrane, will continue until the concentrations of the solute and solvent are equal on either side, osmosis that occurs in bacterial cells causes changes in their size, volume and viability
when the 2 solutions on either side of the membrane are of equal concentrations
greater concentration of solute inside the cell than outside, causes water to be drawn inside the cell causing swelling to the point of busting, this process is called plasmoptysis
greater amount of solute outside the cell than inside, draws water out of the cell, this shrinking process is called plasmolysis
what happens to bacterial cells when placed in a hypertonic enviroment?
it will shrink in size
what happens to bacterial cells when placed in a hypotonic enviroment?
will increase in size
what happens tobacterial cells when placed in a isotonic enviroment?
will show no appreciable change
require only inorganic substances for growth, self-sufficient and able to produce their own nutrients, free-living and do not associate with a living host or cause disease
organisms that require one or more organic compounds for growth
are human pathogens autortrophic or heterogenic?
all pathogenic organisms are heterotrophic
to prefer the condition-"not named"
prefer the absence of O2 but can survive in its presence
preferes the presence of free atmospheric O2 to grow well but can survive without it
prefers dead organic matter but can survive minimally with living organic matter
prefers living organic matter but can survive minimally with dead organic matter "wants to be a parasite"
strict or obligate aerobes
must have free atmospheric oxygen as found in the air
strict or obligate anaerobes
require the absence of free atomospheric oxygen, then acquire O2 for metabolism by breaking down food sorces that contain oxygen
strict or obligate parasites
require living organic matter for nutrition "must have a living host"
strict or obligate saprophytes
require dead organic matter for nutrition
require increased level of carbon dioxide
need only small amounts of O2, it may not grow better, but can survive in the presence of free atomosheric O2
what are the external influences that may affect the genetic make-up of a bacterial cell?
External: temperature of growth
exposure to chemicals or radiant energy
kind of culture medium length of time grown artifically
an alteration in the DNA sequence causing a change in form-usually lethal
transformation: donor cells dies and releases DNA into the medium this DNA breaks up into many small fragments, a receipient cell picks up the fragments of this DNA and incorporates it as its own
sexual form of reproduction, 2 cells unite by a sex pilus, DNA slowly transfers from one to the other, as this occurs this pilus breaks allowing only a portion of the DNA to transfer, this fragment of DNA then recombines with the DNA of the recipient cell causing changes
indirect transfer of DNA by a virus, a virus carries a fragment of DNA from the cell where it was formed and enters a new cell, the virus takes over the controls of the cell and the genetic material is incorporated into the DNA of the new cell
what is the sexual form of reproduction that bacteria may utilize?
as the cells contiune to divide the mass of cells they become visible to the human eye-this forms a bacterial colony
a visible mass of bacterial cells growing on a soild surface
what substance acts to carry nutrients into and wastes of the cell?
how much of a cell's weight is provided by water?
75-80% of the total cell weight
know the temperature ranges associated with each of the following-
Cryophiles/Psychrophiles: 0-15 C
Mesophiles: 25-45 C
Thermophiles: Above 45 C
Classification of bacteria in relation to temperature range: cryophiles/psychrophiles:
prefer cold 0-15 C
Classification of bacteria in relation to temperature range: mesophiles-
prefer mid-range temperatures between 25-45 C
Classification of bacteria in relation to temperature range: thermophiles-
prefer hot temperatures above 45 C, will not cause disease because the human body temprature is to low for them to survive
are human pathogens cryophiles, mesophiles, or thermophiles?
most human pathogens are found in this group
lowest temperature at which a particular organism will grow
highest temperature at which a particular organism will grow
temperature at which an organism prefers to grow and will grow fastest