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WorksheetsLab 8 control of Microorganisms
Total questions: 28
Worksheet time: 16mins
Two basic ways of controlling of Microorganisms
Killing & inhibiting
Disinfecting & destruction
Preservation & heating
Inoculation & pre drying
We need to control microorganism in order to
Keep microorganisms alive and healthy
To prevent transmission of disease & infections
To prevent unwanted microbial Contaminations
To allow microorganisms transfer from one area to another
Agents which kill cells are called
Cidal agents
Static agents
Killer cells
Agents which inhibit the growth of cells (without killing them) are referred to as
Cidal agents
Static agents
Killer cells
Choose all physical agents of controlling microorganisms
Radiation
Filtration
Heavy metals
Desiccation
Antibiotics
Choose all the chemical methods of controlling microorganisms
Antiseptic
Antibiotics
Osmotic pressure
High or low temperatures
Disinfectants
These are agents that inhibit or kill microorganisms on living tissue.
• Examples are iodine and mouthwash.
Disinfectants
Antiseptics
Sanitizers
Antibiotics
These are agents that inhibit or kill microorganisms on non-living surfaces
• Examples are phenolic compounds, formaldehyde, heavy metals and detergents.
Disinfectants
Antiseptics
Sanitizers
Antibiotics
They are agents that reduce microbial numbers to a safe level but may not completely eliminate them.
Disinfectants
Antiseptics
Sanitizers
Antibiotics
Are biosynthetic substances. They are isolated from biological sources: from microorganisms to kill or inhibit the growth of other microorganisms.
Disinfectants
Antiseptics
Sanitizers
Antibiotics
Choose all modes of action of antibiotics
Inhibition of cell wall synthesis
Disruption of cell membrane
Synthesis of nucleic acids
Inhibition of protein synthesis
Destruction of cytoplasm
(a) Is a procedure commonly used in clinical labs to determine antimicrobial susceptibility.
When the zone of inhibition is larger, then
The antibiotic is very effective
The antibiotic is not effective
Effects of antibiotics on bacteria growth is an example of
Qualitative test
Quantitative test
________are the most resistant of all living organisms in their capacity to survive under adverse physical and chemical conditions.
Bacterial Cell walls
Cell membrane
Bacterial spores
_______ is the death of a population of microorganisms due to exposure to an elevated temperature.
Thermal death
Thermal death time
Thermal death point
Programmed cell death
The _______incinerates the microorganisms.
Dry heat of an oven
Heat of an open flame
Moist heat from an autoclave
_______causes the complete removal of water, which is lethal for biological structures
Dry heat of an oven
Heat of an open flame
Moist heat from an autoclave
________causes the proteins in the sample to coagulate in a way that is analogous to the coagulation of the proteins of an egg to form the familiar cooked egg white.
Dry heat of an oven
Heat of an open flame
Moist heat from an autoclave
_______ is how long it takes to kill a specific bacterium at a specific temperature in a water-based solution.
Thermal death
Thermal death time
Thermal death point
Programmed cell death
Thermophilic bacteria can tolerate high temperatures and will have a thermal death time that is longer than the more heat-sensitive bacterium.
True
False
________is an example of a thermophilic bacteria that can tolerate high temperatures
Thermophilus Aquatica
Escherichia coli
Mycobacterium
_______ is defined as the lowest temperature that will completely kill a population of a target microorganism within 10 minutes.
Thermal death
Thermal death time
Thermal death point
Programmed cell death
Thermal death also involves the destruction of the membranes surrounding microorganisms such as bacteria
True
False
How does high temperatures causes destruction of the membranes surrounding microorganisms such as bacteria
By providing ultra violet heat to the membranes which causes denaturation
By causing the phospholipid constituents of cell membrane to dissolve thus destroying membrane structures
By disinfecting the cell wall of the bacteria very efficiently
How does high temperatures causes destruction of the nucleic acid of the target microorgan
The High heat will result in the disassociation of the two DNA strands.
The low energy heatwill result in disassociation of the cell wall
The high heat will disinfect the cell membranes
The high heat will inhibit the growth of nucleic acids
_________was originally developed for food canning and has found applications in cosmetics, producing salmonella-free feeds for animals and pharmaceuticals.
Ultraviolet radiation
Osmotic pressure
Thermal death time
Thermal death point
The thermal death time of microorganisms can vary, depending on the _______ of the microbes.
Thermal tolerance
Cell wall
Cell membrane
Nucleic acid
