Microbial Habitats Flashcards
The array of resources, physical
and biotic factors that are
present in an area, such as to
support the survival and
reproduction of a particular
species.
habitat
habitat is an array of resources, ___
and ___factors that are
present in an area, such as to
support the survival and
reproduction of a particular
species.
physical
biotic
A species habitat can be seen
as the physical manifestation of
its ecological ___.
niche
can be seen
as the physical manifestation of
its ecological niche
species habitat
s a distinct geographical region with specific climate, vegetation, and animal life.
biome
Bacteria and archaea reproduce ___only
asexually
Bacteria and archaea most commonly engage in a process known as
binary fission
where a single cell splits into two equally sized cells
binary fission
Other, less common of microbial reproduction processes can include
multiple fission
budding
sporulation
It has been determined that in a ____ (no food added, no wastes removed) bacteria will grow in a predictable pattern
close system or batch culture
four distinct phases of growth of growth curve
lag phase
exponential or log phase
stationary phase
death or decline phase
is an adaptation period, where the bacteria are adjusting to their new conditions.
lag phase
The length of the ___phase can vary considerably, based on how different the conditions are from the conditions that the bacteria came from, as well as the condition of the bacterial cells themselves.
lag
Actively growing cells transferred from one type of media into the same type of media, with the same environmental conditions, will have the shortest ___period
lag
Damaged cells will have a long ___period, since they must repair themselves before they can engage in reproduction.
lag
Typically cells in the lag period are synthesizing
RNA, enzymes, essential metabolites
typical cells are adjusting to environmental changes in their new environment (or media) such as
changes in temperature, pH, or oxygen availability
is marked by predictable doublings of the population, where 1 cell become 2 cells, becomes 4, becomes 8 etc.
exponential or log phase
Cells in the ____phase of growth are the healthiest and most uniform, which explains why most experiments utilize cells from this phase.
exponential or log phase
Due to the predictability of growth in this phase, this phase can be used to mathematically calculate the time it takes for the bacterial population to double in number, known as the
generation time
lternatively one can rely on the fixed relationship between the initial number of cells at the start of the exponential phase and the number of cells after some period of time, which can be expressed by:
N = No2^n
can be represented by t/n, with t being the specified period of time in minutes, hours, days, or months.
generation time
At some point the bacterial population runs out of an essential nutrient/chemical or its growth is inhibited by its own waste products (it is a closed container, remember?) or lack of physical space, causing the cells to enter into the
stationary phase
t this point the number of new cells being produced is equal to the number of cells dying off or growth has entirely ceased, resulting in a flattening out of growth on the growth curve.
stationary phase