Micro Lab Topic 1: The Microbial World

identify the guidelines for safety in the lab

1. Wear PPE: lab coat, goggles and gloves

2. Disinfect the benchtop with 10% NaCl

3. Wash hands and put on gloves

4. Clean any bacterial spills with 25 % NaCl

what is 10 % bleach used for

to disinfect the benchtops before any lab processes take place to reduce cross contamination

Define Ubiquity

• Ubiquity means present everywhere

• microorganism are ubiquitous which means they are present everywhere

Define fomites

• Fomites are microbial reservoirs or sources that play an active role in the spread of disease

• animate fomites are those like armpit, toe and face

• inanimate fomites are sources like faucets, doorknobs and toilet seats

define a nosocomial infection

a disease acquired in a hospital setting

define a bacterial colony **

1. All cells in a colony are derived from one cell

2. all cells are genetically alike

why are agar media plates inverted when placed in the incubator or refridgerator

to inhibit the condensation from interfering with the colonies

describe the function of the occular lense

• has 10X magnification

describe the function of the objective lense

it has four magnifications which are 4X, 10X, 40X, and 100X

how would total magnification be calculated

the ocular X the objective

• 10x X 100X= 1000X

what does the condenser lense do

condenses light rays from the source and concentrates them into a cone that is focused on the specimen on the slide

what does the iris diaphragm do?

controls the amount of light that enters the objective lense

what does the stage adjustment knob do

adjusts the position of the slide

define magnification

The ability of a lens to enlarge an object

Describe the difference between a simple and compound microscope

• A simple microscope only has one lens

• A compound microscope has two sets of magnifying lenses combined to enlarge objects

what is resolution/ resolving power

• Resolution is the ability of a lens to show detail

• resolving power is the minimum distance between two objects where they still appear as separate

what are the two factors that enhance resolution

1. The wavelength of light used

2. the numerical aperture

• the shorter the wavelength the greater the resolution

what knob should you use with 100X

only use fine focus

what would an increase in numerical aperture mean…

an increase in resolution

why is oil used with 100X objective

• immersion oil is used with 100X lens because oil has nearly the same refractive index as glass which allows oil to bridge the gap between the glass slide and lense to refraction= enhances the resolution

explain the difference between eukaryotic and prokaryotic cells

• Eukaryotic cells have membrane-bound organelles and a nucleus

vs

• Prokaryotic cells are simple and small with a nucleoid

What is the function of neutrophils in innate immunity