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
Neisseria meningitidis is cultured on chocolate agar, a medium containing red blood cells that help cultivate the fastidious Neisseria bacterium to detectable levels. What type of growth medium is chocolate agar based on the description?
Enriched
Which of the following types of media are NOT correctly matched with their description?
- Differential media—exploit differences between two species that grow equally well
- Selective media—favor the growth of one organism over another
- Synthetic media—nutrient rich but poorly defined
Synthetic media - nutrient rich but poorly defined
What is the fastest way to measure cell density?
Spectrometer (optical density)
A student who was trying to determine the concentration of Escherichia coli in a sample completed a total plate count assay. After plating 1mL of the 10-6dilution tube and incubating the plate at 37oC for 24 hours the student counted 210 colonies on the plate. What is the CFU/mL of the original sample?
2.1 x 10^8 cfu/mL
You notice something is growing in a 100ml pot of liquid soap. You took 1ml of this liquid soap and performed a serial dilution and plate to determine the number of bacteria per 1ml in the liquid soap. From the 1:100,000 dilution tube, you plated out 0.1ml and counted of 37 colonies. How many bacteria were present in 1ml of soap (cfu/1ml)?
3.7 x 10^7 cfu/1ml
One cell with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours? (Assuming all cells divide by binary fission in log phase and remained viable).
32
Five cells with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours? (Assuming all cells divide by binary fission in log phase and remained viable).
160
A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a pie with 10 E. coli cells in log phase when he uses his finger to test whether it is done. By the time you purchase the pie, there are 2560 E. coli cells in it. How many generations did the cells go through between the initial inoculation and the time you bought the pie?
7
All of the following statements about ABC transporters are true EXCEPT
- They are the largest family of transporters.
- The are found only in prokaryotes.
- They require energy.
- They can be used for import and export.
They are found only in prokaryotes
Which of the following catabolic cycles are mismatched with their end products (a single round of each cycle)?
- Glycolysis: 2 ATP, 2 NADH, 2 Pyruvates
- All are matched correctly
- Pentose Phosphate Pathway: 1 ATP, 2 NADPH, Carbohydrates for biosynthesis
- Entner-Doudoroff: 1 ATP, 1 NADH, 2 Pyruvates, 1 FADH2
Entner-Doudoroff: 1 ATP, 1 NADH, 2 Pyruvates, and 1 FADH2
In Glycolysis, _____ ATP are invested and ______ ATP are created.
2, 4
Which metabolic pathway produces NADPH but NOT NADH?
Pentose phosphate pathway
The enzyme pyruvate kinase catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate; the phosphate group is transferred from ADP to ATP. This reaction is an example of:
ATP synthesis by substrate level phosphorylation
Which of the following is TRUE with respect to the redox pair NAD+/NADH?
- When NAD+ accepts electrons it becomes reduced to NADH
- NADH donate electrons to electron transport system and gets oxidized to NAD+
The terms phototroph and chemotroph refer to an organism’s source of ____ and/or_____ . (pick more than one answer).
- energy
- carbon
You feed E. coli 3 glucose molecules. How many net ATP are created ONLY through EMP Glycolysis?
6
Glycolysis and fermentation does not require oxygen.
TRUE
Which of the following are TRUE about eukaryote genomes.
- Generally, Eukaryote genome is larger than bacterial genome
- Eukaryote chromosome is linear
- Eukaryote genome mainly contain noncoding DNA
- Eukaryotic genomes are organised in operon
- Eukaryotic genomes are circular like archaeal genome
- generally, eukaryote genome is larger than bacterial genome
- eukaryote chromosome is linear
- eukaryote genome mainly contain noncoding DNA
Which of the following is NOT TRUE about plasmids
- Without them cells will not survive
- Found in archaea, bacteria and eukaryotic microbes
- They are usually circular
- They can be transferred horizontally from one cell to another cell
Without them cells will not survive
You isolate a piece of DNA from a microorganism you cultivated from your teeth. The piece of DNA is 94 kbp in size and is circular. You sequence it and discover that it contains genes for pili, and antibiotic resistance. What is this piece of DNA?
plasmid
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
Like bacteria, archaea have ______.
operon, single circular chromosome, and lack a nuclear membrane
Thermostable DNA polymerases are used in PCR because they
can survive at the high temperatures used to denature DNA
The necessary ingredients for PCR reactions are mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, the primers are artificially synthesized and the DNA template is from an E. coli. The newly synthesized DNA would look like _____.
E. coli DNA
Which of the following is/are TRUE about PCR.
- It requires heating
- It requires DNA polymerase
- It required DNA ligase
- It involves Okazaki fragments
- It requires DNA primers
It requires heating, DNA polymerase, and DNA primers
Genetic change in bacteria can be brought about by which of the following
- transformation
- mutation
- conjugation
- replication
transformation, mutation, conjugation, and replication
You are analyzing a series of mutants that have defects in either transcription or translation. Which of the following mutations would you predict to impact translation?
16S rRNA, 30S subunit, and Shine-Dalgarno sequence
All sigma factors compete for the same number of core RNA polymerase enzymes.
TRUE
Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea or Eukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes?
Archaea and Eukarya have very similar RNA polymerases that are different from bacterial RNA polymerases.
During transcription, if the coding strand of DNA has the sequence 3’ TCTAGGACT 5’, what will the sequence of the transcribed RNA be?
5’ UCAGGAUCU 3’
The termination of transcription can be caused by which of the following?
Transcription of inverted repeats and Rho factor
What is the main difference between a mRNA and tRNA?
Only mRNA gets to be translated to amino acid sequence
The fate of newly made bacterial proteins (nascent proteins) are all of the following EXCEPT
- Exported outside the cytoplasm
- Folded into a 3D structure and remain in the cytoplasm
- Translated back to mRNA so that they can be recycled
- Inserted into the cell membrane
Translated back to mRNA so that they can be recycled
All of the following are bacterial structures responsible for attachment to the host cells or structures EXCEPT
- Protein M of Streptococcus pyogenes
- Type I pili of Escherichia coli
- Lipid A of E.coli
- Pertactin of Bordetella pertussis
- Type IV pili of Neisseria meningitidis
Lipid A of E.coli
Shiga toxins of E. coli O157: H7 mechanism of killing affected cells is due to
Protein synthesis inhibitor
The cholera toxin causes ADP-ribosylation of its target cells and is an example of
an enterotoxin that disrupts function of the intestine
The toxin of _______ consists of two active toxins: an edema factor and a lethal factor.
Bacillus anthracis
Neisseria gonnorrhoeae is a Gram-negative diplococcus that typically causes symptomatic infections in males. The presence of Neisseria gonorrhoeae is urethral pus is diagnostic for gonorrhea in males. What would be observed in a positive Gram stain?
paired red spheres
After staining the background, many strains of B. pertussis resemble the staining pattern shown in the figure below. What structure do they possess that contributes to their virulence?
capsule
Based on your knowledge of microbial genetics and microbial pathogenesis, where do you think the genetic information for endotoxins are located?
chromosomes
T. palladium Virulence Factors
Motility
S. aureus virulence factors
alpha toxin, toxic shock syndrome toxin (TSST), exfoliant toxins A&B, and Protein A
H. pylori virulence factors
urease positive and flagella
S. pneumoniae virulence factors
capsule
Exotoxins
are protein toxins made by both Gram-positive and Gram-negative bacteria.
Thick polysaccharide capsules are important virulence assets for
Neisseria meningitides and
Streptococcus pneumonia.
Which of the following is a common genera found in probiotic supplements?
Lactobacillus
The lungs and trachea are sterile areas of our body.
FALSE
Which of following cell types undergoes phagocytosis?
macrophages, neutrophils, monocytes, dendritic cells, and osteoclasts
Reactive oxygen intermediates and reactive nitrogen intermediates produced by phagocytic cells are effective in killing invading microorganisms.
TRUE
What type of cells assist with the take up of microbes in the intestine and release them on the other side for macrophages?
M cells
What portion of the Gram negative cell wall induces an immune response?
Lipid A
Why is innate host resistance a type of nonspecific immune response?
Innate resistance is nonspecific because any foreign material, microorganisms, or antigens encountered by the host are targeted.
Innate immunity involves all of the following host defenses EXCEPT
- production of small peptides that destroy the bacterial membrane.
- secretion of mucus to prevent microbial entry.
- production of antibodies to bind specific pathogen proteins.
- engulfment of microbes by phagocytes.
production of antibodies to bind specific pathogen proteins
A woman falls and suffers a cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will act first in eliminating microbes at the site of cut?
Neutrophils
Which type(s) of antigen-presenting cell can activate T cells?
- Macrophages
- B cells
- Dendritic cells
All of the above
