Infection & Immunity - Mock Quiz 1
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Which of the following is NOT considered a typical component of the 3 domains?
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Eucarya
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Archaea
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Bacteria
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Animalia
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About This Quiz
Mock quiz for I&I on Monday! Good luck =) This is only over the first lecture, I have not yet gone over the other ones.
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- 2.
While out on a field research experiment with your colleagues, you discover a brand new microorganism. Being the astute student that you are, you recognize that the microorganism is a prokaryote due to the presence of which of the following structures?
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Ribosomes
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Nucleus
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Mitochondria
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Golgi Apparatus
Correct Answer
A. RibosomesExplanation
Don't forget that Prokaryotes have a different set of ribosomes than Eukaryotes! You can differentiate the two by their sedimentation factors, denoted by 70S versus 80S. Do you know which one belongs to prokaryotes and which one belongs to eukaryotes?Rate this question:
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- 3.
Not only did you discover a brand new microorganism, you decided to classify it under a taxonomic division as well (what a stellar student you are!). From your knowledge of prokaryotes, you decide to classify this microorganism as a bacteria because of their classic morphological shapes which are easily identified in the lab.Which of the following morphologies is NOT typically seen in bacteria?
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Rods
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Helix
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Cocci
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Spirillum
Correct Answer
A. HelixExplanation
In Dr. Else's notes, she lists the morphologies as "Rods, cocci, spherical (spirillum)." (slide 8 on bacteria structure lecture)
I'm not sure why (spirillum) is next to spherical.
I believe cocci are supposed to be sphere shaped and spirillum should be spiral shaped and on its own category. Rod shaped bacteria can be considered baccilus.Rate this question:
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- 4.
One of your close colleagues decides to contest your classification of the previously mentioned microorganism. He claims that what you have discovered is actually a type of Archaea instead of your proposed Bacterium.You can assure your colleague of your confidence that the microorganism at hand is indeed a Bacterium due to the presence of which of the following which is found only in Bacteria?
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Absence of membrane bound organelles
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Spherical shape
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Nucleoid region
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Peptidoglycan cell wall
Correct Answer
A. Peptidoglycan cell wallExplanation
Note: Not sure if this is high yield for future exams, but in the lecture these were in red letters. Peptidoglycan is composed of NAM & NAG, n-acetyl muramic acid and n-acetylglucosamine, respectively.Rate this question:
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- 5.
Amoeba, which are single celled organisms that belong to the genus protozoa, belong in which of the following domains?
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Eukarya
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Bacteria
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Archaea
Correct Answer
A. EukaryaExplanation
Amoeba, being single-celled organisms that belong to the genus protozoa, fall under the domain Eukarya. This domain includes all organisms with eukaryotic cells, which have a nucleus enclosed within a membrane. Bacteria and Archaea, on the other hand, belong to the domains Bacteria and Archaea, respectively, as they have prokaryotic cells lacking a nucleus.Rate this question:
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- 6.
True or False. Viruses are considered obligate intracellular parasites.
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True
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False
Correct Answer
A. TrueExplanation
The above is considered true due to viruses requiring a host cell in order to replicate.Rate this question:
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- 7.
What is the main difference between a prion and a virus?
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Viruses are considered infectious agents, prions are not
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Prions are responsible for more severe diseases such as Mad Cow
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Viruses do not contain protein, whereas prions are all protein
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Prions lack nucleic acid
Correct Answer
A. Prions lack nucleic acidExplanation
Choice 1 is incorrect because both are considered infectious agents.
Choice 2 is incorrect because it is hard to quantify what is a more "severe" disease. Viruses can cause severe diseases such as Human Immunodeficiency Virus.
If you chose choice 3, remember that viruses have a protein coat surrounding their nucleic acid!Rate this question:
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- 8.
Bacterial ribosomes consist of a 30S subunit and a 50S subunit. Given the above information, what is the svedberg (sedimentation unit) of a bacterial ribosome?
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60S
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70S
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80S
Correct Answer
A. 70SExplanation
Becareful with this question. Even though bacterial ribosomes consist of a 30S and 50S subunit, they do not add to be 30+50 = 80.
Note that 80S is the sedimentation unit for Eukaryotic ribosomes.Rate this question:
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- 9.
The electron transport chain and consequently the metabolic processes of respiration are located where in a prokaryote?
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On the cytoplasmic membrane
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On the mitochondrial membrane
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Within the cytoplasm
Correct Answer
A. On the cytoplasmic membraneExplanation
Keep in mind that prokaryotes do not typically have mitochondria.Rate this question:
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- 10.
*This might be a tricky question if you didn't catch it in lecture, but if you think it through for a bit the answer might be more apparent.* The gram stain is a procedure that allows researchers to differentiate between gram(+) and gram(-) prokaryotes. Which of the steps in the gram stain is absolutely critical in being able to differentiate between the two types of prokaryotes?
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Step 1 - Crystal Violet
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Step 2 - Iodine
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Step 3 - Alcohol
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Step 4 - Satranin
Correct Answer
A. Step 3 - AlcoholExplanation
Steps 1 and 2 apply the primary stain which colors all of the bacterium purple.
Step 3 is the key step in the gram stain because the application of alcohol is the phase where gram negative cells become colorless (decolorizer phase).
Step 4 is the counter stain phase which colors all of the colorless cells into a reddish/pinkish hue.
If step 3 was not performed, all of the cells would remain purple regardless of the application of a counter stain, making differentiation between gram positives and gram negatives difficult and impractical.Rate this question:
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- 11.
Differentiating between gram (+) and gram (-) bacteria is important due to their morphological differences and the the ability of drugs to target these differences.Which of the following accurately describes these differences between gram (+) and gram (-) cell walls?
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Gram (+) have two, thick peptidoglycan cell walls
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Gram (-) have two, lipid bilayer cell walls
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Gram (-) have two, thin peptidoglycan cell walls
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Gram (+) have two, lipid bilayer cell walls
Correct Answer
A. Gram (-) have two, lipid bilayer cell wallsExplanation
Gram (+) cells have a single, thick peptidoglycan layer in addition to a single cytoplasmic membrane
Gram (-) cells have an OUTER lipid bilayer and a cytoplasmic lipid bilayer, and sandwiched in-between these two layers is a single thin peptidoglycan cell wall. The space between the two lipid bilayers is called the periplasmic space and is filled with a gel-like fluid called periplasm.Rate this question:
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- 12.
For gram (-) prokaryotes, the electron transport chain responsible for respiration is located where?
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Outer lipid bilayer
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Peptidoglycan layer
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Inner lipid bilayer
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Cytoplasm
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Mitochondrial membrane
Correct Answer
A. Inner lipid bilayerExplanation
The inner lipid bilayer is referred to as the cytoplasmic membrane and is the correct location for the electron transport chain in gram (-) prokaryotes.
By now you should be able to rule out choice E for prokaryotes :)Rate this question:
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- 13.
A gel-like layer that allows the adherence of other microorganisms onto it to form a community is known as which of the following?
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Glycocalyx
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Capsule
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Slime
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Biofilm
Correct Answer
A. BiofilmExplanation
A biofilm is a gel-like layer that allows the adherence of other microorganisms onto it to form a community. This community can consist of various types of microorganisms, such as bacteria, fungi, and algae. The biofilm provides protection and support for the microorganisms, allowing them to thrive and survive in different environments. It also enables the microorganisms within the biofilm to communicate and coordinate their activities, making them more resistant to antibiotics and immune responses.Rate this question:
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- 14.
Teichoic acid and lipopolysaccharides (LPS) are important components of bacterial cell walls. Which of the following statements is true regarding Teichoic acid and LPS?
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Teichoic acid is found only on gram (-) cell walls
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Teichoic acid is also known as an endotoxin
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LPS is a component of gram (+) cell walls
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LPS is also known as an endotoxin
Correct Answer
A. LPS is also known as an endotoxinExplanation
Teichoic acid is found on gram (+) cell walls
LPS is a component of gram (-) cell walls and is specifically located on the outer lipid cell membrane. LPS has inherent toxic activity and is considered an endotoxin.Rate this question:
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- 15.
Between Teichoic acid and LPS, which of the two can produce a condition known as Disseminated intravascular coagulation (DIC)?
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Teichoic Acid
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Lipopolysaccharides
Correct Answer
A. LipopolysaccharidesExplanation
Lipopolysaccharides (LPS) can produce a condition known as Disseminated Intravascular Coagulation (DIC). LPS is a component of the outer membrane of Gram-negative bacteria and is released during bacterial infection. When LPS enters the bloodstream, it triggers an excessive immune response, leading to the activation of blood clotting factors and the formation of blood clots throughout the body. This widespread clotting can block blood vessels and disrupt normal blood flow, leading to organ damage and the development of DIC. Teichoic acid, on the other hand, is a component of the cell wall of Gram-positive bacteria and is not associated with DIC.Rate this question:
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- 16.
Your friend is suffering from a severe stomach ache after drinking some unidentified fluid that he found laying around in lecture hall 1. He is confused by the presence of this illness because he claims that he boiled the water for a prolonged period of time and that it should have wiped out any microorganisms in the liquid. With your knowledge of microorganisms and their defensive tactics, which of the following would you expect to find in the liquid that he drank, which would explain your friend's sickness?
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A thick layer of protective glycocalyx
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Well defined fimbriae
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The presence of a biofilm
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Endospores
Correct Answer
A. EndosporesExplanation
The presence of endospores in the liquid would explain your friend's sickness. Endospores are a type of dormant structure formed by some bacteria as a defense mechanism against harsh conditions. They are highly resistant to heat, chemicals, and other environmental stresses, which allows them to survive boiling temperatures. Therefore, even if your friend boiled the water for a prolonged period of time, any bacteria present in the liquid could have formed endospores and survived. When ingested, these endospores can germinate and cause illness, leading to your friend's stomach ache.Rate this question:
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- 17.
One last first order question that you might have missed if you glanced over the notes quickly :pWhich of the following is NOT considered a part of a flagella, which is a long protein structure used for motility in bacteria?
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Filament
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Hook
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Pillus
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Basal Body
Correct Answer
A. PillusExplanation
A pilus is not considered a part of a flagella. Flagella are long protein structures used by bacteria for motility. The filament is the long, whip-like part of the flagella that extends outward from the cell. The hook is a curved region that connects the filament to the basal body, which is the motor that drives the rotation of the flagella. However, a pilus is a different structure found in bacteria that is involved in processes such as attachment to surfaces or transfer of genetic material. Therefore, the correct answer is "Pillus".Rate this question:
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Mar 19, 2023Quiz Edited by
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Feb 27, 2011Quiz Created by
Andrewteh
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