Final Prep for Exam 1 Flashcards
(46 cards)
Acid-fast bacterial cell walls are produced by the genus __________________________. Two diseases caused by this genus include ________________________ and __________________________.
3-8 Acid-Fast Stain
- Mycobacterium
- Lung tuberculosis
- Leprosy
Acid-fast cell walls are primarily made of ____________________ _________. Consequently, these cells are sticky and waxy.
3-8 Acid-Fast Stain
- 60% mycolic acid
Describe how acid-fast bacteria can to survive for longer in their environment. Give at least 3 ways.
3-8 Acid-Fast Stain
- Adherence factor
- Protection against phagocytic digestion
- Protects against dehydration
- Chemical protection (antibiotics and disinfectants)
Describe why carbolfuchsin dye must be heated and steamed during the acid-fast staining procedure.
3-8 Acid-Fast Stain
- Carbolfuchsin is lipid soluble and penetrates the waxy cell wall when steamed as outer surface is softened
After the acid-fast staining procedure, acid-fast cells will have the color ____________________ while non-acid-fast cells will have the color _____________________.
3-8 Acid-Fast Stain
- Pink
- Blue
During the last step of the acid-fast staining procedure, methylene blue is applied for 1 minute and then rinsed off. Explain why only some cells absorb the blue dye.
3-8 Acid-Fast Stain
- Acid-Fast positive cells have mycolic acid layer that can resist methylene blue staining.
When working with acid-fast bacteria, an inoculating ________________ (rather than a needle) should be used to obtain and mix the bacteria into an emulsion during the smear preparation. Why is this important?
3-8 Acid-Fast Stain
- Loop
- Becuase mycobacterium is sticky and would be hard to get on the stain with a needle
The non-pathogenic acid-fast genus and species of bacterium used in this experiment is called __________________ ____________________ and may cause an odor on the skin referred to as _________________ when it overgrows or is not washed by regular bathing.
3-8 Acid-Fast Stain
- Mycobacterium smegmatis
- Smegma
_________________________ _________________________. Although it does not cause disease, it does cause a condition called _____________________ when it overgrows on human skin.
3-8 Acid-Fast Stain
- Mycobacterium smegmatis
- Panniculitis
All fermentation pathways start with the compound ____________________, produced by _______________________. (process)
5-4 Methyl Red and Voges-Proskauer Test
- Pyruvate
- Glycolysis
The only carbon-containing compound in citrate medium is ______________________. Why do organisms need a carbon source?
5-9 Citrate Test
- Citrate
- To make all macro molecules
The only nitrogen source in citrate medium is ________________________. Why do organisms need a nitrogen source (to make which 2 macromolecules)?
5-9 Citrate Test
- Ammonium dihydrogen phosphate
- Amino acids and nucleotides (DNA, RNA)
In a medium where citrate is the only available carbon source, bacteria that possess the enzyme ________________________________ can transport the citrate molecules into the cell and metabolize them.
5-9 Citrate Test
- Citrate Permease
The pH indicator in citrate medium, bromothymol blue, is _________________ at pH 6.9 and ________________ at pH 7.6.
5-9 Citrate Test
- Green
- Blue
Bacteria that survive in this medium and utilize the citrate create an _____________________ (increase or decrease?) in the pH of the medium.
5-9 Citrate Test
- Increase
Describe a positive result in this medium. Why does the pH indicator in the medium change color in a positive test? Indicate the name of the product and the relative pH (acidic or basic) that caused the color change.
5-9 Citrate Test
- Positive test shows utilization of citrate through breakdown of Ammonium dihydrogen phosphate which causes increase in pH leading to blue color change
Describe a negative result in this medium. Why is there no growth in a negative result?
5-9 Citrate Test
- Negative is green with no growth. if it is green with growth it is still positive as there likely has not been enough alkaline products produced yet
- There will be no growth as citrate could not be utilized and no alkaline products were produced
If there is growth on citrate medium after incubation but no color change, this is considered a ________________________ result.
5-9 Citrate Test
Positive
Citrate utilization is one part of a test series referred to as IMViC; these letters stand for the 4 tests:
5-9 Citrate Test
I: Indole
M: Methyl Red
Vi: Voges-Prskauer
C: Citrate
The presence of ammonium hydroxide in the medium is INDIRECT evidence that the bacterium has broken down __________.
5-9 Citrate Test
- Citrate
- Nitrogen is necessary for growth as is carbon so if basic products are produced it indicates the use of citrate as well.
What is a polysaccharide?
5-13 Starch Hydrolysis
A polysaccharide is a type of macromolecule made up of many sugar units.
Why will starch not pass through the bacterial cell (plasma) membrane?
5-13 Starch Hydrolysis
Starch is too large to pass through the bacterial cell membrane.
Bacterial enzymes that can hydrolyze starch are __________ enzymes, namely __________ and __________.
5-13 Starch Hydrolysis
- Amylolytic enzymes
- Alpha-amylase
- Beta-amylase.
The overall reaction for the hydrolysis of starch involves breaking the polysaccharide down to __________.
5-13 Starch Hydrolysis
The overall reaction breaks starch down to glucose and maltose.
