MI final
A microbiologist wants to introduce a new gene into the genome of two different strains of bacteria and has to decide which gene transfer method to use in the experiment. The experiment has the following parameters: the two strains require different type of agar to survive and cannot be plated together. The agar that will be used has DNase, an enzyme that degrades naked DNA. The new gene has already been inserted into a bacteriophage. Given the above parameters, which method is best suited to give the best results?
transduction
The nucleotide strands of DNA are oriented in opposite directions in a structure that is described as:
anti-parallel
Which part of the bacterial cell helps to identify if it is gram positive or gram negative?
cell wall
In the BLAST sequencing program, what does the 0% value of E-value represents?
0% chance that this sequence was randomly with the query sequence
Your supervisor provides you with a 10.0 mg/mL solution of Bovine Serum Albumin (BSA), and asks you to make a 5 step 10-fold serial dilution at each step. if you add 10 μL 10.0 mg/mL BSA to 90 μL of diluent and you perform the same dilution 5 times. what is the total dilution factor at the last step (last tube)?
1 * 10^-5
For the items listed below, indicate whether the description is true for the type of DNA: 1. All DNA 2. Prokaryotic DNA 3. Eukaryotic DNA 4. Plasmid DNA A. Linear, very long pieces of DNA with many thousands of genes and contained in the nucleus B. Made of four nitrogenous bases and a helical structure of repeating nucleotides C. Long circular DNA with several thousand genes D. Small rings of DNA with only a few genes floating in the cytoplasm
1. B 2. C 3. A 4. D
Find the correct example for each of the biochemical mechanism that may cause antimicrobial resistance 1. mutation 2. destruction/inactivation 3. efflux A. A gene in bacteria that produces enzymes capable of degrading antibiotics B. A channel that can export antibiotics out of the bacteria C. Change in the DNA that can cause a change in the enzyme Gyrase which is the target of the antibiotic
1. C 2. A 3. B
Your supervisor provides you with a 10.0 mg/mL solution of Bovine Serum Albumin (BSA), and asks you to make a 5 step 10-fold serial dilution at each step. What is the dilution factor if you add 10 μL 10.0 mg/mL BSA to 90 μL of diluent?
1:10 dilution
How many grams is 2.6 kg?
2.6 x 10^3
Which solution is the most concentrated? 50ug/uL 5ug/uL 5mg/mL 5g/L
5mg/mL
During an antibiotic ELISA test for meningitis, the lab technician performing the procedure forgot to wash out the enzyme linked secondary antibody from the plastic wells before adding the chromogenic substrate. What is the most likely ELISA result from this procedural error?
A positive assay because the enzyme will oxidize the substrate leading to a color change
Which of the following is NOT a way that a bacterium can acquire antibiotic resistance?
Acquiring resistance gene from its host's cells
A patient visits the doctor after feeling ill and running a fever for the last 4 days. The physician needs to determine what pathogen is causing the illness. Which of the following is the best course of action to identify the pathogen?
Amplify the sample with primers specific to known pathogens, then sequence the products and analyze the results with BLAST
All of the following are medical interventions expect:
Artificial Sweetener in soda
Suppose you are studying two different strains of bacteria that have not been identified. You first conduct a Gram stain of the bacteria. Bacteria 1 does not retain the crystal violet stain. Bacteria 2 retains the crystal violet stain. What can you infer about Bacteria 1 and 2?
Bacteria 1 is Gram negative, bacteria 2 is Gram positive
How are drugs that block the synthesis of folic acid able to maintain selective toxicity?
Bacteria must synthesize folic acid, while humans acquire it from their diet
Why are viral infections especially difficult to treat?
Because they rely upon their host cells for the majority of their metabolic functions
The best treatment for an unknown viral disease is
Bed rest and plenty of Fluids
In DNA double helix, the two DNA chains are held together by:
Hydrogen bonds between the pair of bases
Streptococci are gram positive bacteria that cause sore throat and other infections in human. Why is Penicillin prescribed to the patients with strep throat?
It prevents the formation of functional cell wall
Strategies for combating drug resistance include all but which practice? Random distribution of free prescription antibiotics to underdeveloped countries Responsible use of drugs by patients Restrictions on the use of antibiotics in animal feeds Limitation of non-medical uses of antibiotics in humans
Random distribution of free prescription antibiotics to underdeveloped countries
You are prescribed an antibiotic for a bacterial illness and take the medication as prescribed. Which of the following is accurate?
The bacterial strains least resistant to the antibiotic will die first
How do the DNA molecules in various species differ from one another?
The number of genes and non-coding regions
Which of the following is not a category of antimicrobial (antibiotic) drugs?
Those that inhibit mRNA processing in the nucleus
What is the purpose of Kirby-Bauer antibiotic sensitivity test?
To determine whether or not bacteria are susceptible or resistant to different antibiotics
Which of the following statements is an application of Bioinformatics that is currently used in the Biomedical field?
Utilizing an ELISA test to determine the concentration of antigens in a patient's blood sample
Drugs that affect the bacterial cell wall are active only against what type of cells?
Young, actively growing
Mary has been diagnosed with an infectious disease. The flowchart shows her relationships with people she has come in contact with over the last week. Using the information in the flowchart, which three people should be tested first to determine if they are also infected?
Zack, Sydnee & Kevin
Any measure whose purpose is to improve health or alter the course of a disease is called
a medical intervention
What medical intervention can be used to treat the outbreak of a bacterial infectious disease?
administrating antibiotics for the infected individual
Which statement is correct? antigens need to attach to antibodies antigens are an immune response to foreign bodies that enter your body antibodies only flag the antigens antibodies are formed to phagocyte antigens
antibodies only flag the antigens
Which sequence is correct in running the ELISA experiment?
antigen, primary antibody, secondary antibody, enzyme
Students in a Medical Interventions class conducted an experiment in which they mixed E. coli I, containing a gene on the chromosomal DNA for streptomycin resistance with coli II, which contained a gene in plasmid DNA for ampicillin resistance. The students were able to create a bacterial strain that was restistant to both antibiotics. One student, Paco, was sure that the bacteria transferred the gene from strain I to strain II by transduction. His three lab partners arguments are shown below: Gertrude: No, that cannot be correct because transduction involved transferring DNA from the plasmid of one bacteria to the plasmid of another. Ecoli I does not have the gene on a plasmid. Bubba: I am pretty sure that it could not have been through transduction, since transduction involves a viral vector to transmit the gene. We kept our lab sterile, so I do not see how a bacteriaphage could have infected our cultures. Sasha: Transduction is the one where free DNA is taken up by similar bacteria. Since these are both strains of e-coli bacteria, if some of our cells from the first strain died, the DNA segment that coded for the gene could have been taken up by bacteria in the second strain. So I think you might be right after all, Paco. Which of the students have provided the most correct point of view?
bubba
Which answer is correct in explaining how do antibiotics work without harming the surrounding human cells. by affecting structures that bacterial cells have but human cells don't antibiotics do harm the surrounding human cells inhibit the activity of enzymes at the cell membrane level inhibit protein synthesis at ribosomal level
by affecting structures that bacterial cells have but human cells don't
What cellular components is only found in pathogenic bacteria and serves as a barrier against WBC's?
capsule
In an experiment, a bacterial cell copied a piece of its own DNA. The cell then transferred the plasmid to another bacterial cell through cellular contact. The transferred DNA included coding for antibiotic resistance. Which transfer method did the bacterial cell use to gain antibiotic resistance?
conjugation
PBS buffer (phosphate buffered saline) is used in ELISA, what is the role of this buffer?
does not allow a change in PH and keeps the PH at 3.4 which is the same as human blood
When preparing sequencing reactions tubes, each of the four dNTPs (regular A,T,C,G nucleotides) and ddNTPs ( fluorescent A,T,C,G nucleotides) are added. Which are used in the highest concentration?
dNTPs
What is the purpose of DNA sequencing?
determines the order of nucleotides in a DNA fragment
When doing an ELISA test, the substrate binds to the ___________ in order to cause a color change?
enzyme
which one is an example of ELISA in everyday life? Making Vaccine Antibiotic prescription Pregnancy test Specific colors in clothing and garments
pregnancy test
When DNA replicates, each original strand of DNA serves as a template for a new strand. This is called what type of replication?
semi-conservative replication
Which of these conditions is MOST likely to respond to antibiotic treatment?
strep throat
During bacterial conjugation, plasmid replication occurs in...
the donor only
What happens if during ELISA, you forgot to add primary antibody to your wells, but proceeded to add the secondary antibody instead?
the wells will show a negative result
What is not true about antibodies?
they attack and kill antigen
Why is ELISA performed?
to determine the amount of protein present
Which of the following is not a unit for measuring concentration?
ul/ml
Which is true of an indirect ELISA test (like the one we did in class)?
wells are first coated with antigen from the infected patient
Why is PCR used in the process of DNA sequencing?
when the amount of DNA is too small and more DNA is required for testing
Protein concentration are often measured on a spectrophotometer using the "BCA assay". The total protein concentration is exhibited by color change. If you had to generate a standard curve for a BCA protein assay, using BCA concentration (mg/mL) and Average absorbance in nm; which axis would you use for the absorbance?
y axis
