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Medical Microbiology 1-15 > Lecture 11 > Flashcards

Lecture 11 Flashcards

1
Q

At what ideal temperature ranges microorganisms grow?

A

-14 degrees celsius - 113 degrees celsius.

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2
Q

Define (Tmin).

A

The lowest temperature at which growth occurs.

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3
Q

Define (Tmax).

A

The highest temperature at which growth can occur.

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4
Q

Define (Topt).

A

Growth is the most rapid and optimum.

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5
Q

True or false. Each microbes can only grow within a temperature range that is characteristic of their own species.

A

True.

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6
Q

What are the temperature ranges for the growth of Escherichia Coli.

A

8-47 degrees celsius.

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7
Q

What is a cardinal growth?

A

Three key temperatures Tmax, Tmin and Topt.

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8
Q

What are the cardinal temperatures for E.Coli

A

Tmax-47 degrees celsius
Tmin-8 degrees celsius
Topt-37 degrees celsius (body temperature).

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9
Q

True or false. Survival occurs at temperatures below Tmin but death occurs above Tmax.

A

True.

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10
Q

What three groups are microbes divided into considering temperature range for growth?

A

1-thermophiles
2-mesopholes
3-psychorophiles and psychrotrophs

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11
Q

True or false. Thermophiles grow at higher temperatures thanks mesophiles and mesophiles grow at a higher temp than psychrophiles and psychrotrophs.

A

True.

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12
Q

What is E.coli considered?

A

Mesophile

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13
Q

What can psychrophiles and psychrotrophs do that mesophiles and thermophiles can’t?

A

Grow at temperatures around 0 degrees celsius.

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14
Q

What is distinguishes psychrophile from psychrotrophs?

A

They have a lower max temp for growth- specifically 20 degrees celsius.

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15
Q

Define termoduric

A

Termoduric describes microbes that can survive exposure to temperatures above their Tmax.

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16
Q

Explain lambda, f and C for the following formula of electromagnetic radiation, (lambda)f=c

A

lambda=wavelenght
f-frequency
c=velocity

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17
Q

Define ionizing radiation

A

X-rays and gamma are of enough energy to ionize molecules (remove electron from an atom).

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18
Q

Define non-ionizing radiations

A

Certain ultra violet has less energy and excites molecules- increase atomic electron energy.

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19
Q

When speaking if ultraviolet rays- what wavelength have the greatest microbicidal efficiency?

A

260 nm

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20
Q

Name two places where germicide lamps utilized and what are there functions?

A

1-These lamps are utilized in hospital operating rooms.
2-on contaminated surfaces in the dairy industry.
These lamps are used to reduced the size of microbial populations.

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21
Q

True or false. Ultraviolet rights penetrate matter well. Elaborate.

A

False. They do not. As a consequence, the microbicidal action is mostly on the surfaces.

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22
Q

True or false. Ultraviolet rays can either kill microbes or cause mutation in them.

A

True

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23
Q

True or false. The DNA is not specifically affected when speaking of ultraviolet rays effects.

A

False. The DNA is specifically affected.

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24
Q

What wavelength do x-rays include?

A

1nm - 10nm

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25
How are x-rays produces?
By the interaction from a fast moving electron with atomic electrons or atomic nuclei.
26
True or false. X-rays are lethal to microorganisms?
True
27
True or false. They do not penetrate matter well.
False, they do penetrate well.
28
True or false. X-rays cause mutations in microorganisms.
True
29
Give 2 points as to why it is impractical to use x-rays to reduce the size of microbial population.
1-expensive to produce in quantity | 2-They are difficult to use efficiently as they are given off in all directions.
30
What sizes are gamma rays considered to be?
From 0.001 nm - 1 nm
31
True or false. Gamma rays are edited from certain radioactive isotopes?
True
32
True or false. Gamma rays are not lethal to microorganisms.
False. They are lethal.
33
Gamma rays have shorter wavelengths and a higher energy compared to what other rays?
X-rays
34
What are more penetrating? Gamma rays or x-rays?
Gamma rays
35
Gamma rays are very penetrating and can sterilize materials of considerable thickness. What food industry most utilize these types of rays.
The food industry to sterilize meat, poultry and packaged foods.
36
What type of medical things are gamma rays used to sterilize?
Antibiotics, hormones, sutures, plastic materials such as syringes.
37
True or false. Is there concern that food industries utilize gamma rays as sterilization there could be potential in making the food carcinogenic?
True.
38
When referring to acoustic radiation, what does cps stand for?
Cycles per second.
39
How many cps are sonic waves? supersonic waves? and ultrasonic waves?
12,000-16,000 cps, larger than 16,000 cps and larger than 200,000 cps.
40
Acoustic radiation is not used to reduced the size of microbial population, but rather...(finish the sentence).
in research laboratories to disrupt microbial cells so intracellular constituents can be extracted i.e intracellular enzymes.
41
By what means is the disruption of the microbial cell?
Sonication
42
What does sonication mean?
The use of acoustic radiation
43
Explain the process of sonication.
The microbial cel is suspended in a fluid and subjected by acoustic radiation with specific energy for a specific time.
44
What is considered to be of sufficient energy.
20,000 cps
45
Name the three microbes that are most resistant to acoustic radiation.
1-Acid-fast bacteria and endospores 2-Cocci are more resistant to bacilli 3-Gram-positive bacilli are more resistant to Gram-negative bacilli.
46
What is the min, optimum and max pH ranges for E.coli
Min. 4.4 Opt. 6-7 Max. 9
47
What are the min, optimum and max pH ranges for S. pneumoniae
Min. 6.5 Opt. 7.8 Max. 8.3
48
Explains the process of oxidation when speaking of electrons.
The substance will lose electrons.
49
Explain the process of reduction when speaking of electrons.
The substance will gain electrons.
50
What do we consider the pair of reactions when speaking or reduction and oxidation?
Redox reactions.
51
What is the method of measurable value used to measure the potential tendency of a substance to undergo oxidation or reduction?
An O-R potential
52
What do substances with negative O-R potentials tend to undergo?
Oxidation
53
What do substances with positive O-R potentials tend to undergo?
Reduction
54
True or false. In order for a microbe to grow in a medium, the medium must have an appropriate O-R potential.
True.
55
Define osmosis
The diffusion of solvent molecule through a semipermeable membrane.
56
True or false. The cytoplasmic membrane is semipermeable?
True.
57
Define hypotonic medium.
Has a higher solute concentration that the cell.
58
Define plasmolysis.
Waters moves from the area of lower solute concentration (the cell) to the area of higher solute concentration (the medium)
59
Define what a osmotic lysis is.
When the cell sweets ans bursts.
60
What concentration of NaCl is harmful to bacteria?
Greater than 1%
61
Name 3 types of bacteria that are able to withstand larger NaCl concentrations and their percentage.
1-Indegenous to the sea: 3.5-4% 2- Bacteria of the Dead Sea and the Great Salt Lake of Utah: 29 % 3-Bacteria that grow in pickling brines: 20-30%
62
Generally speaking, at what percentage are bacteria inhibited by NaCl and sugar?
NaCl: 10-15% Sugar: 50-70%
63
What is the termed used to define the mechanism of microbial inhibition?
Plasmolysis
64
True or false, you can preserve foods by salting or sugaring?
True.
65
True or false. The microbes are not killed by plasmolysis, it can be a reversible process.
True
66
Define desiccation
Drying process which causes cessation of metabolic activity.
67
What follows cessation in desiccation of cell.
Decrease in viable cells.
68
The longevity of the cells post desiccation varies on what two factors?
1. The microbe itself | 2. The medium in which the microbe is desiccated.
69
True of false. Desiccation is not a method of preserving foods. Elaborate
False. It is- as long as it's kept dry.
70
Define Lyophilization.
Also known as freeze drying where the material is first frozen then dried.
71
True or false. Lyophilization microbe remain viable for years.
True
72
Define a mutation.
It's a change in nucleotide sequence of DNA.
73
Define genetic recombination.
A formation of a new chromosome from DNA contributed by 2 other organisms.
74
What is the new chromosome called after a generic recombination? Name the new formation in bacteria (there is the formation of a new chromosome and...)
Recombinant chromosome. In bacteria there is also the formation of a new plasmid.
75
In bacteria, genetic recombination is brought about what three processes?
1: Transformation 2: Transduction 3: Conjugation
76
When speaking of genetic recombination, define the transformation process.
The recipient takes a naked DNA from the environment and integrates it to the chromosome.
77
When speaking of genetic recombination, define the transduction process.
A bacteriophage is the vector, it then carries the DNA form the donor bacterium, which gets replicated, to the recipient bacterium. The DNA is then integrated in the chromosome.
78
When speaking of genetic recombination, define the conjugation process.
Cell-to-cell contact occurs by two cells by means of the F plus processed by the donor. The F plus then contracts is and brings it to two cells closer together. DNA is transferred by a way of conjugation bridge. The DNA is finally integrated in the chromosome.

Medical Microbiology 1-15 (15 decks)

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