part 3 Flashcards
bacteria which grow below 20°C (cold temp)
psychrophiles
grow between 20-40°C (moderate temp)
mesophiles
most pathogenic bacteria
mesophiles
wide range 5-43°C
pseudomonas
narrow range 30-39°C
Gonococcus
bacteria which grow at higher temp 60-80°C
thermophiles
up to 250°C
bacillus stearothermophilus
average ph requirement of most bacteria, which matches ph in human body environment
7.2-7.6
bacteria grow in acidic ph
ex. lactobacilli in ph=3 and fungi
acidophilic
some bacteria grow in alkaline ph
alkaliphiles
ph 10.5
alakaligenes
light
most bacteria prefer darkness for growth
some bacteria that require sunlight are called
phototropic
exposure to light may influence
pigment production
they form a pigment only on exposure to light and not when incubated in the dark
Photochromogenic mycobacteria
how many percent of NaCl (sodium chloride) are added to culture media to provide suitable osmolarity
0.5% NaCl
sudden exposure to hypertonic solutions may cause osmotic withdrawal of water and shrinkage of protoplasm. this occurs more readily in gram negative than in gram positive bacteria
plasmolysis
shrinkage is called?
crenation
if the cell is a bacterial cell, having a rigid cell wall, does not shrink. instead, the cell membrane and cytoplasm shrink away from the cell. this condition is known as?
plasmolysis
if the cell is a bacterial cell, having a rigid cell wall, when placed in a hypotonic solution, the cell may not burst. but the fluid pressure within the cell increases greatly
plasmoptysis
if the pressure becomes so great that the cell ruptures, the escape of cytoplasm from the cell is referred to as?
plasmoptysis
CELL swells up and sometimes bursts when place into
hypotonic solution
of the cell bursts the bursting is called
hemolysis
those microbes that prefer salty environments, such as concentrated salt water found in great salt lake and salt evaporation ponds are called
halophilic
organisms that do not prefer living in salty environments but capable of surviving are called
haloduric organisms
growth of one organism favours growth of another organism.
ex. staphylococcus aureus streaked across haemophilus influenza favours its growth
symbiosis
growth of one organism is detrimental to the other
ex. pseudomonas hampers growth of gonococci
antagonism
the study of genetics
heredity
an organisms ____ is its complete collection of genes
genotype (or genome)
an organisms ___ refers to its physical trait
phenotype
an organisms ____ is the manifestation of that organisms genotype
phenotype
direct all functions of the cell
genes
a change in a DNA molecule (genetic alteration) that is transmissible to offspring is called
mutation
what are the 3 categories of bacterial genetics mutation
beneficial mutations
harmful mutations
silent mutations
mutation rate ( the rate at which mutations occur) can be increased by exposing cells to physical or chemical agents called
mutagens
the organism containing the mutation is called?
mutant
ways to acquire new genetic information
lysogenic conversion
transduction
transformation
conjugation
an extrachromosal DNA molecule is called?
plasmid
an organism that acquires plasmid acquire new…
genes
in lysogenic conversion ____ inject their DNA into a bacterial cell
temperate phages
the phage DNA integrates into the bacterial chromosome but does not cause the lytic cycle to occur. this is known as
lysogeny
the bacterial cell exhibit new properties, directed by the viral genes. this is referred to as?
lysogenic conversion
“to carry across”
transduction
in ____ bacterial genetic material is “carried across” from one bacterial cell to another by a bacterial virus, thus, in ____ bacteria acquire new bacterial genes.
transduction
only small amount of ____are transferred by transduction
genetic material
transfer of portion of DNA from one bacteria to another by bacteriophages
- phage injects DNA
- phage enzyme breaks down host DNA
3-4. cell created new phages,including phage and host DNA
5-6. transducting phage inserts donor DNA - donor DNA included in recipients chromosomes due to recombination
a bacterial cell becomes genetically transformed following the uptake of DNA fragments (“naked DNA”) from its environments
transformation
the ability to absorb naked DNA into the cell is called
competence
bacteria capable of absorbing naked DNA are said to
competent bacteria
specialized type of pilus
sex pilus
involves a specialized type of pilus called sex pilus
conjugation
bacterial cell with a sex pilus
donor cell
a bacterial cell with a sex pilus attaches sex pilus to another bacterial cell called
recipient cell
some genetic material usually a plasmid is transferred from the donor cell to the recipient cell through a
conjugate pore
a plasmid that contains multiple genes for antibiotic resistance is known as
resistance factor or R-factor
a bacterial cell that receives an R-factor becomes a
“superbug”
involves technique to transfer eukaryotic genes (particularly human genes) into easily cultured cells to manufacture important gene products
genetic engineering or recombinant DNA technology
frequently used as vehicles for inserting genes into cells
plasmid
assemblages of bacterial cell attached to a surface and enclosed in an adhesive matrix that is the product of excretion by
cells and cell death
is typically a mixture of polysaccharides, protein, and nucleic acids that bind the cell together
matrix
a bacterial cell grown on surface, they commonly form
biofilms
