Chapter 3- pt 2 Microorganisms And microbiology

Question 1

Acidophiles

Answer 1

Organism that grows best at low ph (less than 6)

Question 2

Organisms that grow best at high ph (more than 9)

Answer 2

Alakaliphiles

Question 3

Microbial culture contains buffers to maintain constant pH. Why?

Answer 3

Each organism has an optimal ph for growth
Some bacteria produce acids that decreases pH
Some bacteria produce amino acids that increases pH

Question 4

What is aW (water activity)?

Answer 4

Amount of free water. Available water for microorganism
The amount of water that is interacting with ions and polar compound solutions.

Ratio or vapour pressure of air in equilibrium with a substance or solution of vapour pressure of pure water

Question 5

Cytoplasm (inside of cell) has higher solute concentration than environment. Where will water move?

Answer 5

Water will move into cells resulting to TURGOR PRESSURE

Question 6

Positive water balance

Answer 6

Turgor pressure

Question 7

Cytoplasm (inside of cell) has lower solute concentration than environment (higher solute concentration). Where will water move?

Answer 7

Water will move out of cell to environment

Question 8

Microorganism that grows best at reduced water potential. Have specific requirement for NACL.

Answer 8

Halophiles

Question 9

Organism that requires high levels of NaCl for growth. At what percent?

Answer 9

Extreme halophiles

15-30%

Question 10

Halotolerant

Answer 10

Organism that can tolerate some reduction in water activity of environment but generally grow best at lower solute concentrations

Question 11

Osmophiles

Answer 11

Microorganism that can grow at high sugar as solute

Question 12

Xerophiles

Answer 12

Organism that able to grow in very dry environments

Question 13

Compounds used by cells to counteract low water activity in surrounding environment

Answer 13

Compatible solutes

Question 14

Organism that requires oxygen to live

Answer 14

Obligate aerobes

Question 15

Strict anaerobe

Answer 15

Do not require o2. Dies at presence of o2

Question 16

Facultative aerobe

Answer 16

Can live with or without 02, but grows well if presence of 02

Question 17

Aeroloterant aerobes

Answer 17

Can tolerate o2 and grow in presence even though they cannot use it.

Question 18

Microaerophiles

Answer 18

Can use oxygen when its present at levels reduced from that in air (2-10%)

Question 19

Differences in oxygen use/ tolerance can be distinguish sed using _____

Answer 19

Thioglycolate broth

Question 20

State at which zone they grow in thioglycolate broth
Obligate aerobe
Strict anaerobe
Facultative anaerobe
Microaerophile
Aerotolerant anaerobe

Answer 20

Obligate aerobe - oxic zone (top)
Strict anaerobe- anoxic zone (bottom)
Facultative anaerobe - throughout tube but better in oxic (top)
Microaerophile -narrow band between oxic and anoxic
Aerotolerant anaerobe- grows well throughout tube

Question 21

Chemicals used that can be add in media to reduce oxygen

Answer 21

Reducing agent

Question 22

Toxic forms of oxygen

Answer 22

Superoxide anion
Hydrogen peroxide
Hydroxyl radical

Question 23

Enzymes to neutralize toxic forms of oxygen

Answer 23

Catalase
Peroxidase
Superoxide dismutase
Superoxide reductase

Question 24

What types of microorganism lacks enzymes that can neutralize toxic forms of oxygen

Answer 24

Obligate anaerobes

Question 25

Growth control by heat examples of general principles

Answer 25

Sterilization Inhibition Decontamination Disinfection

Question 26

Kills all viable microorganism within a growth medium

Answer 26

Sterlization

Question 27

Inhibition

Answer 27

Limits microbial growth. No killing

Question 28

Treatment of an obj make it safe to handle

Answer 28

Decontamination

Question 29

Directly targets removal of all pathogens, not necessarily all microorganism

Answer 29

Disinfection

Question 30

Most widely used method of controlling microbial growth

Answer 30

Heat sterilization

Question 31

Decimal reduction time

Answer 31

Time it takes for a 10 fold reduction in bacterial numbers

Question 32

Endospores

Answer 32

Resistant cells, that can survive heat that would rapidly kill vegetative cells

Question 33

Pasteurization

Answer 33

Use of precise controlled heat to reduce microbial load in heat sensitive liquids. Does not kill microorganism **different than sterlization

Question 34

LTHT and STHT

Answer 34

63C, 30 mins; 72C, 15 secs

Question 35

Sealed device that uses steam under pressure. Allows temp of water to reach above 100C. Uses moist heat at what temp? And time?

Answer 35

Autoclave | 121C for 15 mins

Question 36

Electromagnetic radiation that produces ions and other reactive molecules that generates electrons, hydroxyl radicals, and hydride radicals

Answer 36

Ionizing radiation

Question 37

Filtration and give example.

Answer 37

Avoid use of heat on sensitive liquids and gases. Uses pores of filters. HEPA FILTER AND MEMBRANE FILTER

Question 38

Two examples of pore sizes

Answer 38

5 and 02. Micrometer

Question 39

Antimicrobial agents can be classified as

Answer 39

Bacteriostatic Bacteriocidal Bacteriolytic

Question 40

Prevents microbial growth as long as Antimicrobial agent is present

Answer 40

Bacteriostatic

Question 41

Antimicrobial agent that kills the cell but does not lyse them

Answer 41

Bacteriocidal

Question 42

Bacteriolytic

Answer 42

Antimicrobial agent that kills the cell and lyse them

Question 43

Minimum inhibitory concentration (mic)

Answer 43

Smallest amt or an agent needed to inhibit growth of microorganism

Question 44

Use solid media. An antimicrobial agent that is added to filter paper disc. Forms zone of inhibition

Answer 44

Disc diffusion assay

Question 45

Antimicrobial microbial agents can be classified into 2 categories

Answer 45

Products to control MO in commercial and industrial applications Products designed to prevent growth of human pathogens inanimate environments and on external body surfaces

Question 46

Example of products to prevent growth of human pathogens in inanimate envr and ext body surfaces.

Answer 46

Sterilant Disinfectant Sanitizer Antiseptic

Question 47

Destroys all MO including endospores

Answer 47

Sterilant

Question 48

Kills MO but not all endospores. Used on inanimate obj

Answer 48

Disinfectant

Question 49

Reduces the number of MO on surfaces

Answer 49

Sanitizers

Question 50

Kills or inhibit growth of MO, but sufficiently non toxic to be applied on living tissues (eg. Mouth wash)

Answer 50

Antiseptic