Missed questions from past exams Flashcards
Besides the nucleoid, two other kinds of DNA molecules that may be present in the cytoplasm of a bacterial cell are ________ and ________.
plasmids; bacteriophages genome
Which of the following mutation types are possible with a deletion or insertion of 1 or 2 nucleotides?
Nonsense mutation and Frameshift mutation
Genes that are part of plasmids are not essential for cell growth.
TRUE
Genetic change in bacteria can be brought about by all of the following EXCEPT
- mutation
- conjugation
- transformation
- replication
replication
During what process do you see ringed catenanes form?
End of DNA replication
Both leading and lagging strands are synthesized 5’ to 3’ direction.
TRUE
All of the following are TRUE about DNA gyrase EXCEPT
- relieves DNA supercoils
- is a type 1 topoisomerase
- introduces negative supercoil
- it is capable of making double strand cut
it is a type 1 topoisomerase
Which of the following molecules will initiate chain termination after they have been incorporated to the growing strand of nucleotides by a polymerase.
- Zidovudine
- Robonucleotide
- 2’,3’ - Dideoxyribonucleotide
- 2’ - Deoxyribonucleotdie
Zidovudine and 2’,3’-Dideoxyribonucleotide
RNA primer is required in rolling circle replication of plasmids
TRUE
Which is NOT TRUE about bacterial transcription?
- Bacterial transcription is different from archaeal transcription
- Can be affected by Actinomycin D
- Can be affected by Rifamycin B
- Requires a separate Helicase enzyme
Requires a separate Helicase enzyme
Antibiotic Streptomycin is designed to inhibit protein synthesis and it is bacteriostatic agent.
FALSE
The following image is a result from Kirby-Bauer Disk Susceptibility test of Staphylococcus aureus against three antibiotics. What can be concluded from the result below?
Staphylococcus aureus is resistant to antibiotic A (no clearing around antibiotic)
Assume that your lab partner swabs the side of his face and uses the swab to inoculate a nutrient agar plate. The next day, he performs a Gram stain on the colonies. They are Gram positive cocci. He is worried that he might be affected by a MRSA. You advise him that he should next look for?
Antimicrobial sensitivity
The best target for development of a new antibiotic against Mycobacterium species would be
mycolic acids
Consider an MIC result of 5 μg/ml of vancomycin for bacterial strain A, 10 μg/ml for strain B, 15 μg/ml for strain C, and 20 μg/ml for strain D. Which bacterial strain can be interpreted as the most resistant to vancomycin?
D
These are some of the antimicrobial agents used to treat human infections. Answer the following question based on the information listed below.
1. Aminoglycosides
2. Cephalosporins
3. Penicillin G
4. Gramicidin
Which of the above numbered antimicrobials can also destroy human cells
only antibiotic number 4
Square planar arrangement of cells that forms when round bacteria remain attached to each other during reproduction are called ________.
Tetrads
The majority of nitrogen in soil and marine environments is fixed by:
Free living bacteria and archaea
After you transferred 1mL from a 10-6 dilution tube into a plate, you counted 207 colonies. How many CFU are present in 1 mL?
Assuming all cells remain viable and in log phase.
2.07 x 108
Longest lag period would most likely be observed if a culture is transferred ___________.
From a complex medium to a minimal medium
You feed #. coli 3 glucose molecules. How many ATP are created ONLY through substrate level phosphorylation?
12
In cultures without oxygen, if S.pyogenes decided to undergo fermentation, what happens to the electrons carried by NADH from glycolysis?
Will be donated to pyruvates
Fermentation produces more energy than anaerobic respiration
FALSE
Which of the following pathways would be fully operational ONLY in respiring bacteria?
TCA
When chemoorganotrophs oxidize an organic energy source, the electrons released are accepted by electron carriers such as NAD+ and FAD. When these reduced electron carriers (NADH and FADH2) in turn donate the electrons to an electron transport chain, the metabolic process is called __________.
Respiration
The significance of the thermophile Thermus aquaticus in microbiology is, due to its ability to ferment different sugars at a very high temperature.
FALSE
Which of the following determines if microorganisms are going to use oxygen or not?
- their ability to use oxygen as a terminal electron acceptor
- their ability to have enzymes that deals with ROS
Invisible living creatures were thought to exist and cause disease long before they were ever observed.
TRUE
All of the following are arguments the support the classification of archaea as a third domain of life apart from bacteria, EXCEPT?
- Archaea are larger in size when compared to bacteria
- archaea rDNA is different from bacterial rDNA
- Microscopic characteristics of archaea are different from bacteria
- Unlike bacteria, archaea cannot cause disease
Unlike bacteria, archaea cannot cause disease
In Griffin’s experiment of transformation, he concluded that protein was the biological molecule that must be “transferring” information to the nonvirulent strain of Streptococcus.
FALSE
Light rays are refracted when they cross the interface between materials with different refractive indices.
TRUE
Prior to staining, smears of microorganisms must be heat fixed in order to __________.
attach them firmly to the slide
The instrument that produces a bright image of the specimen against a dark background is called a
dark-field microscope
Which of the following antibiotics target the peptidoglycan cell wall of bacteria.
Both penicillin and vancomycin
Which of the following is FALSE about bacterial outer membrane?
- It contains a toxic component
- It contains a lipopolysaccharide layer
- It is composed of a phospholipid bilayer
- It is found only in Gram negative bacteria
It is composed of a phospholipid bilayer
Bacteria rotate their flagella clockwise when they try to change direction.
TRUE
