Lecture 5 Flashcards
1
Q
Steam Sterilizing: Autoclave
A
- some contaminant organisms may survive 100˚C
- boiling point increased by pressure
- high boiling point = hotter steam
- at 15 PSI steam from boiling water is 121˚C
2
Q
Filtration of Heat-Labile Compounds
A
- liquids can be passed through filters which contain holes too small for bacteria to pass
- commonly 0.2µm pore size
- useful for solutions that can’t be heated
3
Q
Solutions that Can’t be Heated
A
- heat will sterilize it
- Ammonium Acetate
- Penicilin
- IPTG (a lactose analog)
4
Q
Basic Microscopy
A
- used to visualize objects down to ~0.2µm
- 2 lenses in combo can magnify an object 2000x
- ocular and objective lenses
5
Q
Ocular Lense
A
- making image bigger but not sharper
- empty magnification
6
Q
Objective Lense
A
- 4x, 10x, 40x, 100x
7
Q
Quality of Image Depends on:
A
- thickness of section
- lighting
- quality/cleanliness of lenses
- staining
8
Q
Eyepiece
A
- a magnifying lens, usually about 10x
9
Q
Condenser
A
- focuses the light
10
Q
Iris Diaphragm
A
- controls the amount of light that enter the objective lens
11
Q
Objective Lens
A
- # of lenses that provide different magnifications
- the total magnification is the product of the magnification of the eyepiece lens and the objective lenses
12
Q
How to Focus a Microscope
A
- turn on light, open diaphragm, raise condenser
- select lowest power objective lens
- place slide on stage, use clips/arm
- raise stage to highest or lowest position
- position slide so something is under lens
- use both eyes, adjust eyepieces
- lower slide until object seen
- wiggle slide if must
- select next objective, use ONLY fine focus to adjust microscope
13
Q
Magnification
A
- how big something looks
14
Q
Empty Magnification
A
- a bigger image is useless without more detail
15
Q
Resolution
A
- something that is measured, can be calculated
- increases detail of image
- the smallest resolvable distance between 2 objects
