Lab 20 carbs fermentation and bgalactosidase activity Flashcards


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1

Differentiate between the resolving power and magnifying power of a lens. What is meant by the term parfocal?

Resolving power, the ability to show detail, smaller wavelength greater detail
Magnifying power- ability to make objects appear larger
Parfocal- diff lenses that focus on same image and can be switched without adjusting the microscope as you move through lenses should only use fine

2

Why is the low power objective placed in position when the microscope is stored or carried?

Bc the shortest lens is the least likely to be smashed against a slide

3

Why is oil necessary when using 90x to 100x objective?

Oil has same optical qualities of glass and increases numerical aperture, keeps light from scattering, if no oil only have half a lense

4

What is function of iris diaphragm? The substrate condenser?

Iris diaphragm controls the amount of light passing through the slide or specimen and substage condenser focuses a cone of light on the slide or specimen

5

What is meant by the limit of resolution

It's the shortest distance between two parts on a specimen that can be distinguished by the observer

6

How can you increase the bulb life of your microscope if the bulbs voltage is regulated by a rheostat?

Rheostat is a dimmer, start with lowest power on rheostat and it allows for slow ramping up of power instead of turning lamp on to highest and hottest setting

7

What position should you keep your substage condenser at?

All the way up bc you are looking at very small things

8

What are the 3 bacterial shapes observed?

Bacillus/rod shaped
Crocus/spherical
Spiral shaped

9

How can you increase resolution on microscope?

Make sure lense clean including condenser
Scope must be properly adjusted

10

In micro, what is most common used objective? Explain

100x bc looking at organisms that at micrometers in size

11

In micro what is most common ocular used? Explain

10x if higher ocular would have more mag but wouldn't be able to see detail

12

If 5x instead of 10x ocular a used with same objectives, what mags would be achieved?

5x * 10x. 50x
* 20x. 100x
*40x. 200x
*100x. 500x

13

Why is it necessary to calibrate the ocular micrometer with each objective?

Ocular micrometer is a series of lines, to calibrate u need to line up at each lense

14

In the prepared slides, which organism was largest

Fungi

15

When identifying microorganisms why should a wet mount be used to make messurements

The specimen is alive in a wet mount and if you heat fixed an organism it shrinks and is not an accurate measurement

16

What is a stage micrometer

Microscope slide with scale marked on surface, tiny ruler embedded in glass