Bonnie's Set - Micro Lab - Exam 2

Front 1

What is transformation?

Back 1

The Process by which competent bacterial cells pick up DNA from the environment and make use of the genes it carries.

Front 2

What genes and other regions are in the pGLO plasmid and what are their functions?

Back 2

The pGLO plasmid has been engineered to carry the gene for green florescent protein, genes for antibiotic resistance, the arabinose promoter, a replication origin and the DNA binding protein.

Front 3

What is the purpose of the steps of the pGLO transformation protocol, including calcium chloride and heat shock?

Back 3

The calcium chloride and the heat shock (placing the culture in ice then quickly in a hot bath and back to ice) helps break down the walls of the bacterial cells and help them to become "competent" and accept the pGLO plasmid.

Front 4

Be able to interpret and explain the results of the pGLO experiment. What are the
expected outcomes for growth on the four agar plate types (with and without
ampillicin, arabinose) for both E. coli with and without the plasmid? Why?

Back 4

The "-DNA" plates - growth was expected on the regular LB plate because it was just the bacteria that was shocked and recovered. No growth was expected on the plate with ampicillin because the E. coli was not resistant. Growth was expected on both "+DNA" plates, but the glow was expected only on the plate with arabinose. The arabinose was needed for the glow gene to be expressed.

Front 5

What is a germicide, antiseptic and disinfectant?

Back 5

Germicides are substances designed to reduce the number of pathogens on surfaces, in liquids and on living tissue. Antiseptics are germicides designed for use on living tissue and disinfectants are germicides designed for use on surfaces and liquids.

Front 6

Understand the use-dilution test protocol, including the purposes for the four controls

Back 6

The cultured beads were exposed to 3 different strengths of germicides and there were 4 controls. #1 showed the culture was alive and well. #2 showed no contamination of the nutrient broth. #3 displayed no contamination of the sterile water and #4 displayed no contamination of the sterile bead.

Front 7

What are typical applications where RODAC plates are used?

Back 7

Surfaces in places of food preparation, veterinary, pharmaceutical and medical settings.

Front 8

What issues complicate compliance with good hand-washing standards?

Back 8

Location of sinks, heavy workloads, skin reactions to cleansers, skin dryness, empty soap dispensers, empty towel holders, among many others.

Front 9

What is an antibiotic?

Back 9

Natural antimicrobial agents produced by microorganisms.

Front 10

What are some ways different antibiotics attack bacteria? Know why penicillin is not as effective on Gram negative bacteria.

Back 10

Some attack the bacterial cell wall. Others interfere with biosynthesis reactions. Penicillin inhibits cross-linking of the cell wall's peptidoglycan. The peptidoglycan layer is much thicker in gram positive bacteria and the peptidoglycan layer is protected under the LPS layer in gram negative bacteria, so Penicillin is much more effective on gram positive bacteria.

Front 11

What is antibiotic resistance?

Back 11

The ability of bacteria and other microorganisms to resist the effects of an antibiotic to which they were once sensitive.

Front 12

Be able to determine if an antibiotic shows resistance based on an antibiotic sensitivity test, using a zone diameter interpretive chart.

Back 12

Zone diameter interpretive chart is on page 400 of the lab manual.

Front 13

What are Narrow spectrum and broad spectrum antibiotics?

Back 13

Broad spectrum antibiotics are antibiotics that tend to be effective on a wider range of microorganisms than a narrow spectrum antibiotic.

Front 14

Why do public health agencies routinely test beaches and other water bodies for Escherichia coli (E. coli) and other coliform bacteria?

Back 14

Because many diseases can be spread through fecal transmission.

Front 15

Be able to interpret the results of a membrane filter sample, taking into account dilution.

Back 15

Water is only potable if it contains less than one coliform per 100 mL of sample. If a membrane filter was created using only 10mL of a sample or it was diluted 10mL, then the number of coliforms must be multiplied by 10. Fecal coliforms often are characterized by the colors green or gold with a metallic sheen.

Front 16

What is the appearance of E. coli on EMB agar?

Back 16

Fecal coliforms often are characterized by the colors green or gold with a metallic sheen.

Front 17

What are antibodies and antigens?

Back 17

A substance that stimulates the production of an antibody when introduced into the body. Antigens include toxins, bacteria, viruses, and other foreign substances. An antibody is any of numerous Y -shaped protein molecules produced by B cells as a primary immune defense.

Front 18

What happens during a positive reaction of an ELISA test?

Back 18

The antibodies bind the antigen.

Front 19

Why are ELISAs run in triplicate with positive and negative controls? Be able to interpret ELISA results.

Back 19

The tests are run in triplicate to be sure that it is done properly. If all three turn out the same, there is a greater likelihood that it was done properly. The positive controls show, if all three result in positive, the validity of the antibody serum. The negative controls show that the test was run properly.

Front 20

Be able to interpret the results of a Snyder test.

Back 20

Yellow at 24 hours means high susceptibility to dental caries. Yellow at 48 hours means moderate susceptibility and yellow at 72 hours means slight susceptibility. Staying green or turning yellow after 72 hours is a negative result.

Front 21

What causes the color change seen in Snyder tests?

Back 21

Fermentation.

Front 22

What role do bacteria play in tooth cavity formation?

Back 22

Dental caries is a bacterial infection of the tooth. It is a result of the production of acid by bacterial fermentation of food debris accumulated on the tooth surface.

Front 23

What is epidemiology, mortality, morbidity, incidence rate?

Back 23

Epidemiology is the study of the causes, occurrence, transmission, distribution and prevention of diseases in a population. Mortality rate is the death rate of a particular disease, morbidity rate is the sickness occurrence rate and incidence is the number of new cases in a time period divided by the size of the at risk population at midpoint of the time period.

Front 24

What are cumulative totals? Know how to calculate 4-week totals and incidence rates.

Back 24

The 4 week totals of the month being calculated is the addition of the incidence rates for the first 4 weeks of that month. The next 4 weeks is the total from week 8 minus the previous month's incidence rate.