Genetic Changes
Copy of a plasmid could be transferred to another bacterium via a “bridge” between two adult bacteria. These ____________ are used in mating in gram negative bacteria and could contribute to the spread of drug resistance among bacterial populations.
pili
Are Acid Fast bacteria more sensitive or resistant to alcohol based disinfectant? Explain based on the Acid fast cell wall structure and how alcohol based disinfectant would/would not affect them.
resistant
DNA copies itself by the process in which the "old" strand of DNA is the template upon which "new" strand is synthesized. What property of DNA replication does this reference?
semi conservative replication
In fermentation, the conversion of pyruvate into an organic product is critical to produce what?
NAD+
Echinocandins inhibit synthesis of b-glucan and is an effective control agent for
fungi.
Hfr cells result when an F plasmid integrates into a prokaryotic chromosome. Such cells do not make a pilus. Is this true? Explain.
No.
Salmonella typhi has an outer membrane that is made of LPS with Lipid A component in the cell wall. It is not advisable to treat these types of bacteria with antibiotics late in the infection because
symptoms may get worse, sometimes even causing death.
The enzymes for glucose are constitutive enzymes and are always produced in constant amounts in cells. These enzymes produced by a bacterial species are example of a/an
phenotype.
True or false: Noncompetitive inhibitors are still able to limit enzymatic activity even in the presence of high concentration of substrate, while competitive inhibitors are not. Explain.
True.
Why is it important to complete the full course of antibiotic therapy? What would be the outcome of stopping the treatment after 3 days? Explain the outcome in relation with Natural selection and development of Drug resistance.
-antibiotic resistance
-superinfection
If a microbiologist leaves a plate of Serratia marcescens under ultra violet light, what is likely to occur?
Pyrimidine dimers will form in the DNA of the cells.
An alcohol based disinfectant was used on a table top that was contaminated with Gram positive and Gram negative bacteria. Which of the above bacteria are most likely to have their growth inhibited faster by alcohol based disinfectant? Explain in detail how the alcohol based disinfectant affects their cell wall structures.
Gram negative
Why must the lagging strand of DNA be replicated in short pieces?
DNA polymerase can synthesize in only one direction.
Name the different mechanisms of resistance that bacteria may possess that give them an advantage in the presence of antibiotics.
-rapid efflux
-block entry
-change target molecule
-inactivating enzymes
A useful method or compound for STERILIZING foods such as fresh vegetables:
ionizing radiation
Explain with the help of three applicable methods and mechanisms why the following statement is false: Sexual reproduction is the only mechanism for genetic change.
-conjugation
-transformation
-transduction
Staphylococcus aureus was growing well in a liquid medium (broth medium) that contained a higher than normal concentration of sodium chloride. While it was growing, it became a protoplast due to an unknown mutation. What will be the outcome now?
lose water
A DNA animal virus is replicating. Where is the DNA synthesized?
Nucleus
Which family/group of RNA Viruses could cause cancer? How do these viruses cause cancer? What are the basic steps of this type of viral multiplication cycle?
-Retroviridae
-reverse transcriptase
Chloroquine inhibits the DNA synthesis of the causative agent for malaria and is an effective control agent for
protozoa.
Induced mutations can only be caused because of insertion or deletion of bases in a DNA strand. Is this true?
No.
A patient was suffering from UTI caused by Escherichia coli when due to an unknown mutation the E. coli became spheroplasts. Upon his visit to the clinic, the physician prescribed Ampicillin to control this infection. What will be the effect of Ampicillin on E.coli?
There will be no effect of Ampicillin on E. coli.
Describe in detail how genetic information contained in DNA molecule in prokaryotes results in protein synthesis.
How is it different in Eukaryotes?
DNA--transcription-->RNA--translation-->protein
-nucleus vs cytoplasm
-introns/exons
-simultaneous transcription & translation
-methionine vs formylmethionine
A patient has been prescribed penicillin for Osteomyletis (bone infection) as a result of a deep wound infection caused by Staphylococcus aureus. During which growth phase would the bacteria be most susceptible to penicillin?
Log phase
An agent used to reduce the number of bacteria on a bed pan would most accurately be called a (an)
disinfectant.