LAB EXAM #1 cont. Flashcards
(59 cards)
1
Q
Psychrophiles:
A
- Grow between -5C and 20C
- Found in waters of Antarctic and Arctic
2
Q
Mesophiles:
A
- Grow between 20C and 50C
- Most common temp range for organisms
3
Q
Most pathogens grow between:
A
35C and 40C
4
Q
Thermophiles:
A
- Grow between 50C and 80C
- Found in soils or compost piles
5
Q
Hyperthermophiles:
A
- Grow above 80C
- Found in thermal vents or where there is volcanic activity
6
Q
How does temperature effect metabolic factors in a cell? (3)
A
- Enzyme function or activity
- Cell membrane and transport
- Ribosomes
7
Q
Neutrophils:
A
- Neutral pH
- MOST bacteria are neutrophils
- Some can grow over a range of 2-3 pH units
8
Q
Acidophiles:
A
- Acidic pH
- Ex: Yeast prefers a pH of 4-6
9
Q
Alkaliphiles:
A
- Alkaline pH
- Belong to the genus Bacillus
10
Q
How does bacteria that grows at the extremes of the pH scale maintain their cytoplasm?
A
At a neutral pH to help prevent damage
11
Q
7 physical agents:
A
- Heat: thermal death point, dry heat, moist heat, pasteurization
- Cold: refrigeration, freezing, freeze-drying
- Radiation: ultraviolet light (UV), ionizing radiation, microwave
- Sonic and ultrasonic waves
- Filtration
- Drying
7`. Osmosis
12
Q
Thermal death point:
A
Temp that kills all bacteria in broth in 10 min
13
Q
Dry heat: (3)
A
- Oxidizes molecules
- SLOW penetration
- Metal, glassware
14
Q
Moist heat: (2)
A
- Denatures proteins
- RAPID penetration
15
Q
2 mechanisms of moist heat:
A
- Boiling water: kills vegetative cells not spores
- Autoclave:
- steam under pressure
- kills spores
16
Q
Cold physical agents:
A
Slows enzyme controlled reactions- doesn’t kill
17
Q
Refrigeration:
A
At (-5C), food is good for a few days
18
Q
Freezing: (3)
A
- At (-20C), slows chemical reactions a lot
- At (-78C). stores microbes in glycerol
- Long term storage
19
Q
Freeze-drying:
A
- Lyophilization: microbes dried (vacuum) while frozen
- Long term preservation
20
Q
UV radiation: (3)
A
- 200 nm range
- Damages DNA
- Poor penetration
21
Q
Ionizing radiation: (4)
A
- X-rays, gamma rays
- Damages DNA
- Deep penetration
- Good for plastic
22
Q
Microwave:
A
Lower frequence of radiation
23
Q
Sonic and ultrasonic waves:
A
- Sonication causes cavitation in cell cytoplasm
- Bacteria killed
24
Q
Filtration: (4)
A
- Small pore size: 25um to 0.025um
- Can sterilize
- Good for drugs
- Alternative to pasteurization
25
Drying: (3)
- Ancient practice
- Sun dried food
- Hot air
26
Osmotic pressure:
-High sugar and salt-> hyperosmotic conditions
| A. Plasmolysis: cell ruptures
27
Stage:
Knob that supports microscope slide
28
Lenses:
Oculars, have a magnification of 10X
29
4 microscope objectives in order:
4X: red, scanning
10X: yellow, low power
40X: blue, high power
100X: white, oil immersion
30
Condenser:
- Located under stage
| - Collects and directs light from the lamp to the slide
31
Diaphragm:
Controls the amount of light that enters the condenser
32
Coarse focus knob:
Used with 4x and 10x objectives to bring slide into FOCUS
33
Fine focus knob:
Used with 40x and 100x objectives to SHARPEN image
34
Ability to go from one objective to another and not lose sight of the specimen is called:
Parafocal
35
What parts of the microscope are necessary for cleaning with lens paper?
- oculars
- objectives
- condensers
36
How to center specimen on microscope?
Mechanical stage knobs
37
Purpose of oil immersion:
To bend light-> increasing resolution
38
Where is E. coli found?
Intestines of animals and humans
39
Where is S. aureus found?
Normal flora of body
40
As objective magnification goes up:
Field of view decreases
41
4X diameter of field of view in microns:
5,000
42
10X diameter of field of view in microns:
2,000
43
40X diameter of field of view in microns:
500
44
100X diameter of field of view in microns:
200
45
What happens to serratia marcescens when it reaches 37C or higher?
Loses its enzyme that produces the red pigment-> it is clear
46
Ignaz Semmelweis
Observed that hand washing is important in preventing the spread of diseases
47
3 main groups of the normal flora that inhabit the human skin:
1. Diphtheroids
2. Staphylococci
3. Fungi
48
Nosocomial infections:
- Hopsital acquired infections
| - Ex: Methicillin-resistant S. aureus (MRSA)
49
Diphetheroids:
- Prefer oily regions of skin
| - Degrade fatty secretions in hair follicles
50
Staphylococci: (4)
- Coagulase-negative
- Salt tolerant
- Grow in dry areas
- Beneficial because they produce antimicrobial compounds
51
Fungi:
- Nonpathogenic yeast that uses fatty substances
| - Found on face as flaky skin around nose
52
Disinfectants:
Substances that are applied to inanimate objects to kill or reduce microorganisms. Harsh and damaging to living tissue
53
Antimicrobial:
Agents that kill or inhibit microorganisms
54
Antibiotic:
Low molecular weight antimicrobials that are produced by microorganism that inhibit or kill other bacteria
55
First line of defense that battle diseases:
Antimicrobials and antibiotics
56
Kirby-Bauer method:
Standardized test used to determine the sensitivity or resistance of a bacteria to a antimicrobial agent
57
How is the Kirby-Bauer method performed?
With Mueller-Hinton agar plates and disks that have specific antibiotics and concentrations
58
Responsible for observing penicillin species inhibiting the growth of S. aureus?
Alexander Fleming
59
Responsible for the purification of penicillin:
- Howard Florey
- Norman Heatley
- Ernest Chan
