Chapter 6 and 7

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By: Megan Finney
Created: 2012-10-04
Size: 50 flashcards
Views: 8

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binary fission

reproduction of bacterial cells whereby a single cell splits into two identical daughter cells

budding

genetically identical individual grows off another

Conidiospores (conidia)

naked spores that are not produced in a sac

what are the 4 stages of binary fission?

1. DNA in cytoplasmic membrane

2. DNA duplicate

3. Split

4. 2 daughter cells

Growth curve: lag phase

Bacteria is being shocked in new culture and adjusting

log phase

exponential growth phase

stationary phase

# if cells dividing = # of cells dying

death phase

# of cells dying is greater than the # of cells dividing; due to lack of nutrients or accumulation of toxins or metabolites (ethanol, lactic acid)

Direct Measurement method: Filtration

used to test H2O

Psychrophiles

cold-loving microbes. Optimum growth is 15C.

psychotrophs

Grow fast at fridge temp. but prefers room temp.
0-35°C, opt. = 22°C

mesphiles

25 to 40 degress c. Body Temperature pathogens

thermophiles

grow from 45 C and higher; hot springs, compost piles; some bacteria can grow above 100 C; volcanic under sea vents

Plasmolysis

Cell membrane shrivels when placed in a hypertonic solution

halophiles

require high salt concentration

Autotrophs

Organisms that are able to produce their own food

Trace elements

Only required in minute quantities

Lyophilization

Freeze drying: preservation of food and bacteria, rapid removal of water via vacuum, no crystals.

sepsis

presence of pathological microorganisms or their toxins in the blood

asepsis

without poisons or infection

sterilization

The complete removal or destruction of all viable microorganisms.

COMMERCIAL STERILIZATION

a process of treating canned good aimed at destroying the endospores of Clostridium botulinum

Disinfection

A process that eliminates many or all microorganisms, with the exception of bacterial spores, from inanimate objects.

degerming

removal of microbes by mechanical means

Bacteriostasis

inhibits does not kill microbes

1 log decrease=

90% of population killed

What physical methods can be used for microbial control?

heat;Moist and dry

cold temperatures

desiccation

radiation

flitration

What is thermal death point?

The lowest temperature required to kill all microbes in a sample in 10 minutes

Thermal death time (Tdt)

Shortest length of time required to kill all test microbes at a specific temperature

decimal reduction time

time required to kill 90% of microbial life

drawbacks of autoclaving

Destroys heat labile substances and makes sharp objects dull

Radiation and filtration are only effective methods of _____________

Sterilization

Ionizing radiation

Ionizes water to reduce OH

dessication

Removal of water and often stops growth, but doesn't necessarily kill. Most endospores are resistant to dessication.

Principles of Effective Disinfection.

Concentration of disinfectant, Organic matter, pH, Time.

Phenols and Phenolics

disrupt plasma membrane

disinfectants

biphenols

Hexachlorophene: Not effective against gram - (pseudomonas aeruginosa)

Triclosan: Antimicrobial agent in soaps

Biguamides

Chlorohexidine: Effective against both gram - and +

Halogens

Chlorine: most effective oxidizing agent by disrupting enzyme function.

Fluorine: Can shut down function of thyroid gland.

Iodine: Most effective antiseptic.

Alcohol

Denatures proteins,

Heavy Metals

Denatures proteins

Silver: Impregnated on catheters, artificial heart valves, plastic containers

Copper and Zinc

Pseudomonas aerogenousa

grows on burn sites

Surface active agents

Soap, detergent, Benzalchonium chloride "Quat"

Organic Acids

use as Preservatives

Aldehydes

Very good disinfectant.

Gaseous Sterilizers

Denatures proteins. Ozone, Ethylene Oxide

Plasma Sterilization

Gas excited by electromagnetic field. Both a physical and chemical sterilizer. Free Radicals: Hydroxyl Ions

Supercritical Fluids

CO2 is compressed so it has both liquid and gas properties, used in foods and medical implants.

Oxidizing agents

Hydrogen peroxide:Antiseptic.

Benzoyl peroxide: Salycilic acid, anti-acne medication.

Peracetic Acid: Most effective liquid sterilant. Kills spores

capnophiles

microbes that grow better at high CO2 concentrations.

About this deck

By: Megan Finney
Created: 2012-10-04
Size: 50 flashcards
Views: 8

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis