Quiz Questions Flashcards
Microbes include members of which of the following groups?
Bacteria, archaea, fungi, and viruses
Which of the following scientist–contribution is NOT matched correctly?
- Robert Hooke–built compound microscope
- Robert Koch–founded medical statistics
- Antonie van Leeuwenhoek–discovered individual microbes
- Louis Pasteur–disproved spontaneous generation
Robert Koch - founded medical statistics
Which of the following individuals argued in favor of the theory of spontaneous generation?
John Needham
Koch’s postulates include all the following, EXCEPT
- The isolated pathogen must be used to infect healthy hosts
- The pathogen must be found in every individual suffering from the disease
- A pure culture of the pathogen must be obtained
- Healthy individuals infected with the isolated suspected pathogen must get sick with disease
- The pathogen must be shown to contain toxins
The pathogen must be shown to contain toxins
The first vaccination was performed by _______, and the first antibiotic was discovered by _______.
Edward Jenner; Alexander Fleming
Lithotrophs are organisms that feed on _______ and were discovered by _______.
inorganic material; Sergei Winogradsky
Many scientists tried to disprove spontaneous generation, including Francesco Redi, Lazzaro Spallanzani, and Louis Pasteur. Pasteur performed a series of experiments finally disproving spontaneous generation. How did Pasteur finally succeed in disproving spontaneous generation?
- He devised a special long necked flask
- He was to allow his media access to air without allowing the infectious agent
All of the following belong to one of the four Koch’s postulates to demonstrate the causative agent of a COVID-19 infection, EXCEPT?
- Isolate the antibodies from individuals found to be infected with the COVID-19 virus
- Isolate the viruses from the infected individuals and try to culture them outside the host.
- Re-isolate the viruses from the individuals after they are inoculated with the viruses and show some symptoms of the disease.
- Inoculate a new healthy host with the viruses recovered from the viral culture.
- Identify a host organism infected with COVID-19 and show that the viruses are only found in infected individuals.
Isolate the antibodies from individuals found to be injected with the COVID-19 virus
Which of the following are problem/s not encountered by Koch with would you expect to face when you are trying to apply the four postulates to prove the cause of COVID-19? (Select all that apply)
- Not all SARS Cov-2 virus infected individuals show symptoms.
- SARS Cov-2 virus, unlike Bacillus anthracis bacterium, can not be cultivated in a artificial culture plate. They are usually grown in a live cell culture or fertilized eggs.
- SARS Cov-2 primarly infect humans so it will be hard to find an animal host to test the postulates
What does analysis of 16S rRNA sequences show?
Archaea are classified separately from bacteria
Archaea and Bacteria are classified as prokaryotes because,
Both lack membrane-enclosed organelles
Microbes include members of which of the following groups?
Bacteria, archaea, fungi, and viruses
Which of the following scientists did NOT contribute to the discovery of the identity or structure of the genetic material (DNA)?
Lynn Margulis
Which best defines a living organism that lives inside a larger organism?
Endosymbiont
Which of the following is NOT an evidence for the endosymbiotic theory?
- Mitochondria have circular DNA
- Mitochondrion contains ribosomes
- The nucleus is surrounded by a nuclear membrane
- Mitochondrion has double membrane
The nucleus is surrounded by a nuclear membrane
Ernst Haekel contribution
classified microbes under kingdom Monera
Herbert Copeland contribution
divided Monera into Eukaryotes and Prokaryotes microbes
Robert Whittaker contribution
added fungi as a fifth kingdom
Lynn Margulis contribution
proposed endosymbiotic theory
According to the three-domain model of classification, what are the ancestors of mitochondria?
proteobacteria
According to the three-domain model of classification, what are the ancestors of chloroplast?
Cyanobacteria
What structure does light pass through directly after leaving the condenser in a compound light microscope?
The specimen
If you are using the 10x objective of a compound light microscope, what would be the final magnification?
100x
What types of microscopy have provided the most information about the structure and morphology of Ebola virus?
Scanning electron microscopy and transmission electron microscopy
Which one of the following types of microscopes works the best for observing internal structures of a living cell?
phase contrast microscope
Ebola virus is shaped like a shepherd’s crook and is approximately 970 nm in length, and 80 nm in diameter. Can this virus be readily viewed with a compound light (bright field)?
No, since its diameter is less than the 200 nm limit of resolution of the oil immersion lens
A student was studying a microorganism using a bright-field microscopy. She was unable to resolve the microorganism on her first attempt.Based on the facts learned in class, what would you recommend the student do to increase resolution?
use a lens with higher numerical aperture
What type/s of microscopy will provided sufficient information that can differentiate Gram positive from Gram negative bacteria?
Bright field microscopy and transmission electron microscopy
You are performing Gram staining on a heat-fixed smear of E. coli culture. You have already completed the steps of application of a primary stain crystal violet and a mordant iodine. If you observe the slide under the microscope at this step, what will be the color of the cells?
purple
Gram-positive and Gram-negative cells will have different color when Gram stained properly. For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if decolorizer
(alcohol) step were omitted during staining.
Gram positive and Gram negative would both be purple.
Which of the following structures are unique to a bacterial cell?
peptidoglycan
Bacteria and archaea are different in which of the following?
Cell wall composition, cell membrane composition, and rRNA sequence
Which of the following is/are functions of membrane proteins?
- Structural support
- Secretion
- Detection
- Transport
Structural support, secretion, detection, and transport
What makes the cell envelope of Mycobacterium species unique?
- Can only be stained with Acid Fast staining
- Presence of unique lipids known as mycolic acids
Which arrangement is commonly seen in the Genus Staphylococcus?
clusters
Which part of the lipopolysaccharide (LPS) that is found in the outer membrane of Gram-negative bacteria is also known to hyperactive the human immune system.
Lipid A
These two structures are found in both Gram negative and Gram positive cell envelope?
Peptidoglycan and Phospholipids