MICROBIAL GROWTH AND METABOLISM- MICROBIAL CONTROL Flashcards
defined as a process of increase in the number of cells, cell mass and cell activity
microbial growth
indicators of microbial growth
- Increase in both population size and population mass
- Increase in cell number
- Increase in cell mass
- Increase in Metabolic activity
most bacteria grow by
binary fission
The increase in mass is a consequence of
Anabolic process
main reactions of cell synthesis are
polymerization reactions
process of regeneration of same type of progeny by parent cell is called as
reproductions
In microorganisms’ reproduction takes place by
sexual, asexual as well by vegetative propagation
In case of bacteria, reproduction is defined as ____ of new cells from a parental cell by cell division.
regeneration
The bacterial cell reproduces or regenerate by four major processes
BINARY FISSION
BUDDING
FRAGMENTATION
SPORULATION
normal reproductive method of bacteria
binary fission
single cell divides into two identical cells
binary fission
process by which most prokaryotes replicate
Binary fission
generally involves the separation of a single cell into two more or less identical daughter cells, each containing, among other things, at least one copy of the parental DNA
Binary fission
Most bacteria reproduce by a relatively simple asexual process called
binary fission
The time interval required for a bacterial cell to divide or
for a population of bacterial cells to double is called
generation time
Generation times for bacterial species growing in nature
may be as short as __ or as long as __
15 minutes
several days
parental cell forms a tuber like outgrowth, which after detachment from a parental cell gives rise to new cell with similar phenotypic and genotypic characters
BUDDING
The bacteria reproduce by budding is
Rhodopseudomonas acidophila
The yeast reproduce by budding
S. cerevisea
a mode of asexual reproduction common in filamentous
microorganisms like fungi and filamentous bacteria
Fragmentation
a small fragment is detached or dissociated from parental filament by mechanical damage
reproduction by fragmentation
Reproduction by Fragmentation occurs in filamentous cell of a ___ and filamentous fungi like __
Nocardia species
Aspergillus spp
Cellular events in the cells of certain prokaryotes may change and lead to the formation of new cell types. This type of activity is called
differentiation
Fragmentation: In bacteria dormant or resting structures of four kinds can be produced:
Heat resistant endospores
Exospores
Cysts
Conidia
are formed asexually without union of nuclear material from two different types of cells
Heat resistant endospores
Kind of heat resistant dormant structures produced by
bacteria and Cyanobacteria which were liberated by mother cell before cell lysis and which giving new vegetative structure after germination
Exospores
are formed asexually without union of nuclear material from two different types of cells
Cysts
The dormant structure of the fungus like Actinomycetes is a heat labile asexual spore that is formed at the end of special surface (aerial) cells by a process of fragmentation
Conidia
a process of formation of endospore inside the vegetative cell in nutrient deficient or adverse conditions.
SPORULATION
In some bacteria no internal food reserve, which gain nutrients from exogenous sources for sporulation, such sporulation is called
exogenous sporulation
Cell is asymmetrically partitioned by doubled membrane wall called as
spore septum
Asymmetric cytoplasmic division- Largest one
mother cell
Asymmetric cytoplasmic division- smallest one
forespore
Septum does not have
peptidoglycan
Stage IV: Cortex synthesis- occurs in two sub stages
- deposition of primordial cell wall on inner forespore membrane
- deposition of specific thick layer of peptidoglycan outside the primordial cell wall
Dipicolinic acid to Calcium ratio in most of spores
1:1
In this stage spore become retractile
Stage VI : Maturation
Any process, physical or chemical, that will destroy or remove all viable microorganisms (bacteria, fungi, spores, and virus) from an object or from a
particular environment
Sterilization
Total inactivation of all forms of microbial life in terms of the organism’s ability to reproduce
Sterilization
Is any cleansing technique that mechanically removes microorganisms or reduce the level of contaminants or microbial population to a safe level as determined by public health standards
Sanitization
Growth of microorganisms or the presence of microbial toxins in the blood and other tissues
Sepsis
Any practice that prevents the entry of infectious agents into sterile tissues thus preventing infection
Asepsis
Are used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery and also in the food industry
Aseptic techniques
Are products/chemical agents used for the asepsis of living tissues applied directly to exposed body surfaces (skin, wounds, mucosa) and surgical incision to destroy or inhibit vegetative pathogens
Antiseptics
Applied topically to living tissues
Antiseptics
Refers to the use of physical process or chemical agent (disinfectants) that promotes killing, inhibition, or removal of microorganisms (vegetative or growing form) but not the resistant spores of bacteria
Disinfection
Is an agent used to reduce the viability of a microbial population below a threshold level that causes infection
Disinfectant
Are used on surfaces of inanimate objects (floors, tables)
Disinfectant
▪ meaning to kill
▪ Added when a killing action is implied
▪ a suffix indicating that the antimicrobial agent will kill or destroy a certain group of microorganism
Suffix “cide/cidal”
An agent that kills certain microorganisms
Germicide
An agent that kills bacteria. Most do not kill endospores
Bactericide
An agent that inactivates viruses
Viricide