Lab test #5
Terms
undefined, object
copy deck
- transformation
- The ability of bacteria to take up DNA fragments from the environment and ultimately express the information encoded in the genes of that DNA is called _____________.
- antimicrobial chemotherapy
- Transformation has profound implications for ____________ ____________ because the genes that are taken up by transformation may be genes that code for antibiotic resistance.
- Heat shocks
- _____ ______ both tubes by submerging the bottom 1/2 of the tube into the 42'C waterbath and agitating both of the tubes by gently shaking them back and forth for 90 secs.
- allows DNA to more readily enter the cells.
- What does heat shocking do?
- countable numbers
- What should LB/AMP + plasmid look like?
- Because some of the bacteria will lyse all of the plasmids.
- Why should LB/AMP + plasmid have countable numbers?
- No growth
- What should LB/AMP - plasmid look like?
- lawn
- What should LB - plasmid look like?
- bacteriophage
- a virus that infects bacteria
- Viruses
- ________ are obligate intracellular parasites.
-
synthesize
generate - Viruses can not __________ proteins or _________ ATP and consequently can only replicate inside living host cells.
- lytic cycle
- a phage attaches to the host cell by means of tail fibers that recognize specific receptors on the surface of E.coli.
-
lysozyme
tail sheath - The phage then releases an enzyme, _________, which dissolves part of the bacterial cell wall. The phage ____ _______ then contract and drives the phage core, a hollow tube, through the cell wall injecting its DNA into the host cell.
- high jacks
- The phage then "_____ _____" the machinery of the host cell and the host cell begins to replicate the phage DNA and synthesizes the phage structural components.
- phage DNA
- The phage components are assembled and packaged with the ______ ____ and the host cell disintegrates releasing new phage that in turn can infect other host cells.
- 25
- How long does the lytic cycle take?
- 100-200 new virions
- How many new virions are released at the end of the lytic cycle?
- virion
- a completely assembled virus capable of infecting a cell.
- plaques
- Their effect on agar surface coated with E.coli can be seen clearly as holes in the lawn of bacteria called ________.
- epidemiology
- the science that studies when and where diseases occur and how they are transmitted.
- Infectious diseases
- a disease in which a pathogen invades a susceptible host and carry out at least part of their life cycle in the host.
- Communicable disease
- Any disease that can be spread from one host to another.
- Epidemic
- A disease acquired by many hosts in a given area in short time.
- Pandemic
- a epidemic that occurs worldwide.
- potable
- To assume that our drinking water is _________ (safe to drink) our drinking wateris constantly monitored for both toxic chemicals, and microbial contamination.
-
indicator organism
sewage indicators - It is not practical to look for specific pathogens in out water supply, instead water is screened for ________ ___________ or __________ ___________.
- Sewage indicators
- _______ ________ are consistantly present inhabitants of the intestinal tract and their presense in water is a good indication that fecal material has entered the water supply.
- coliform
- There are two types of indicators that are currently tested for Streptococcus faecalis and __________ bacteria.
- most probable number
- What does MPN stand for?
- the number of coliform bacteria per 100 mL of a water sample.
- What are the units of MPN>
-
Presumptive test
MPN index - In the __________ ____ a set of lactose broth tubes containing Durham tubes is innoculated with the water sample. The presense of a gas bubble in the durham tube indicates a positive reaction. A presumptive MPN is then determined by comparing the number of positive tubes to a standard table called the ______ ______.
- Confirmed test
- In the _________ _____ EMB plates are innoculated with samples from any positive lactose broth tubes from the presumptive test. This media inhibits the growth of gram-positive bacteria while gram-negative bacteria that ferment lactose will grow with distinctive dark purple colonies or produce metallic green sheen on the agar surface.
- Completed test
- In the ___________ _____ a nutrient agar slant and a lactose broth tube are innoculated with colonies from the EMB plates that are consistent with gram - lactose fermenting bacteria. A gram stain is made from the nutrient agar slant to determine if the colonies on the EMB plate are in fact gram - rods. The lactose broth tube contains the pH indicator phenol red and a durham tube and if the bacteria are indeed coliforms the tube will turn yellow and the durham tube will have a gas bubble in it.
- Positive results
- _________ results for all three tests indicate the presence of coliform bacteria in the water.
- Lancefield antigens are classifying streptococcal groups A-O based on different carbohydrates in the cell wall. They are used in order to determine what types of streptococcal infection you have so you can treat it.
- What are Lancefield antigens and how are they used?
- streptolysin O
- inactivated by oxygen
- streptolysin S
- oxygen stable
- catalase test
- If you have beta hemolytic colonies on the throat swab plate what test is done next? (other than a gram stain)
- the hydrogen peroxide would not bubble once poured onto the bacteria.
- What would the reaction look like for the catalase test on Throat swab plate?