Term
| Size of bacillus and coccus |
|
Definition
- Bacillus (rod shaped) - .5 – 1 µm (wide) 1-4 µm (long)
- Coccus - .5 – 1 µm |
|
|
Term
| ocular lens objective lens |
|
Definition
- Ocular lens – eye piece which magnifies 10x
- Objective lens – the lenses close to the stage. There is a 4x , 10x, 40x and 100x lens |
|
|
Term
|
Definition
| - The immersion oil has the same properties as glass therefore the immersion oil “traps” the light and prevents the distortion effect that is seen as a result of the bending of the light waves. |
|
|
Term
|
Definition
- Coccus – 1 single circle
- Diplococcus – 2 circles side by side
- Streptococcus – chain of circles
- Staphylococcus – bunch of circles (like grapes)
- Tetrad – four circle (forming a square)
- Sarcina – eight circles (forming a cube) |
|
|
Term
|
Definition
- Bacillus – single rod
- Streptobacillus – chains of rods
- Coccobacillus – oval and similar to coccus |
|
|
Term
|
Definition
- Vibrio – comma shaped
- Spirillum – a thick, rigid spiral (snake like)
- Spirochete – a thin , flexible spiral (spaghetti like) |
|
|
Term
|
Definition
| culture where all organisms are descendants of the same organism |
|
|
Term
|
Definition
|
|
Term
|
Definition
| method of transferring growing organisms |
|
|
Term
|
Definition
| method of transferring growing organisms while preventing unwanted microorganisms from gaining access. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| a mass of organisms is floating on top of the broth |
|
|
Term
|
Definition
| the organisms appear as a general cloudiness throughout the broth |
|
|
Term
|
Definition
| a mass of organisms appears as a deposit at the bottom of the tube |
|
|
Term
|
Definition
| grow only in the presence of oxygen |
|
|
Term
|
Definition
| require low concentration of oxygen to grow |
|
|
Term
|
Definition
| only grow when there is no oxygen (inhibited or killed by oxygen) |
|
|
Term
|
Definition
| cannot use oxygen to grow but they tolerate it. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| cold loving organisms. Optimum growth temperature is between -5C and 15C |
|
|
Term
|
Definition
| grow best at moderate temperatures. 25C – 45C |
|
|
Term
|
Definition
| heat loving organisms. 45C – 70C |
|
|
Term
|
Definition
| grow at very high temperatures . 70C – 110C |
|
|
Term
|
Definition
| produce pigment during growth |
|
|
Term
|
Definition
| the pigment diffuses out of the bacteria and into the medium (ex: colonies and agar will be colored) |
|
|
Term
|
Definition
| does not diffuse out of the bacteria (only bacteria will be colored) |
|
|
Term
|
Definition
| has agents which will inhibit the growth of one group of organisms while allowing the growth of another (CNA agar allows gram positive to grow but not gram negative) |
|
|
Term
|
Definition
| additives that cause an observable color change in the medium when a particular chemical reaction occurs |
|
|
Term
|
Definition
| additive that enhances the growth of certain organisms |
|
|
Term
|
Definition
| combination of selective and differential – allows the growth of one group of prganisms while inhibiting the growth of another in addition it differentiates those organisms that grow based on whether they can carry out particular chemical reactions (MacConkey agar) |
|
|
Term
|
Definition
CNA - only grows gram positive
MacConkey - grow gram negative and turns pink with acid and orange/red with little to no acid |
|
|
Term
| appearance on MacConkey agar |
|
Definition
a. Escherichia coli – acid - pink
b. Enterobacter aerogenes- no pink – less acid
c. Salmonella – less/no acid - orangeish |
|
|
Term
| the formula for determining the number of CFUs per ml of sample when using plate count technique |
|
Definition
- number of CFUs per ml of sample = the number of colonies x the dilution factor of the plate counted
- Ex: if there were 150 colonies in a plate diluted 1/1,000,000 so you do 150 x 1,000,000 = 150,000,000 CFUs per ml |
|
|
Term
| State the principal behind the direct microscopic method of enumeration |
|
Definition
| - There are 16 squares each of which are 1/20,000,000 of a cc so therefore the big square is 1/1,250,000 of a cc. You count the colonies in the big square and then multiply it by 1,250,000 |
|
|
Term
| formula for determining the number of bacteria per cc of sample when using the direct microscopic method of enumeration |
|
Definition
| - Number of bacteria per cc = the average number of bacteria per large double- lined square x the dilution factor of large square (1,250,000) x any dilution made prior to placing the sample in the counting chamber. |
|
|
Term
|
Definition
| - Used to measure turbidity |
|
|
Term
| State the relationship between absorbance (optical density) and the number of bacteria in a broth sample |
|
Definition
| - The greater number of bacteria the higher the absorbance (directly proportional) |
|
|
Term
| State the relationship between percent light transmitted and the number of bacteria in a broth sample |
|
Definition
| - The greater the number of bacteria the lower the percent light transmitted (inversely proportional) |
|
|
