Final Exam Wooclap Q's

Question 1

NOTE CARD: These first ones are module 1!

Question 2

Which of the following statements is true? Pay attention to the capitalized terms and their definition.

a) The PROPHAGE excised itself from the plant cell’s genome.

b) The uncoated virus, or VIRION, hijacked its host’s machinery.

c) This animal cell is a known host of fourteen different PHAGES.

d) The eukaryote could not eliminate its integrated PROVIRUS.

Answer 2

d) The eukaryote could not eliminate its integrated PROVIRUS.
–> (extra info): A provirus refers to the integrated form of a viral genome within a eukaryotic cell’s DNA, such as in retroviruses like HIV. Once integrated, the provirus becomes part of the host genome and is difficult or impossible for the cell to eliminate.

———– Info on incorrect ones:

a) The PROPHAGE excised itself from the plant cell’s genome.
–> Incorrect. A prophage is the integrated form of a bacteriophage (a virus that infects bacteria) within a bacterial genome, not a plant genome.

b) The uncoated virus, or VIRION, hijacked its host’s machinery.
–> Incorrect. A virion refers to the complete, extracellular form of a virus, including its protective coat. Virions are not “uncoated” by definition.

c) This animal cell is a known host of fourteen different PHAGES.
–> Incorrect. Phages (bacteriophages) infect bacteria, not animal cells.

Question 3

What do all viruses contain?

a) A genome and an envelope

b) A capsid and an envelope

c) A capsid and a genome

d) A capsid, an envelope, and a genome

Answer 3

c) A capsid and a genome
–> All viruses have a genome obviously. And the capsid is the part that directly encloses the genome.

————- Info on incorrect ones:

a) A genome and an envelope
–> Not all viruses have an envelope. Envelopes are derived from the host cell membrane and are only present in some viruses.

b) A capsid and an envelope
–> Not all viruses have an envelope, though all have a capsid.

d) A capsid, an envelope, and a genome
–> Same as above—not all viruses are enveloped.

Question 4

Which structure of a virion protects it from degradation when outside the host?

a) Capsule
b) Capsid
c) Envelop
d) Spikes

Answer 4

b) Capsid
–> The capsid is the protein shell that encases and protects the viral genome (DNA or RNA) from degradation by environmental factors such as enzymes, chemicals, or UV light when the virus is outside a host cell.

————- Info on incorrect ones:

a) Capsule: This term is incorrect in the context of viruses. A “capsule” is associated with some bacteria, not viruses.

c) Envelope: While some viruses have an envelope derived from the host cell membrane, it is fragile and more prone to degradation. The envelope primarily helps with host cell entry, not protection.

d) Spikes: Spikes are glycoproteins found on the surface of enveloped viruses that assist in binding to host cells. They do not protect the virion.

Question 5

Where do most RNA viruses replicate inside the eukaryotic host cell?

a) Cytoplasm
b) Nucleus
c) Endosome
d) Mitochondria

Answer 5

a) Cytoplasm
–> Most RNA viruses replicate in the cytoplasm because they often bring or encode their own RNA-dependent RNA polymerase, which allows them to replicate their genome without relying on the host cell’s nuclear machinery.

————- Info on incorrect ones:

b) Nucleus: Some RNA viruses (e.g., influenza virus) replicate in the nucleus because they need host nuclear enzymes for replication or transcription, but this is the exception, not the rule.

c) Endosome: The endosome is involved in the entry process (e.g., uncoating and release of the viral genome) but is not where replication occurs.
–> An endosome is a membrane-bound compartment inside eukaryotic cells that is part of the cell’s endocytic pathway, which processes and transports materials brought into the cell. It plays a key role in sorting and delivering molecules.

d) Mitochondria: Mitochondria are not used by RNA viruses for replication.

Question 6

Where do most DNA viruses replicate inside the eukaryotic host cell?

a) Cytoplasm
b) Nucleus
c) Endosome
d) Mitochondria

Answer 6

b) Nucleus
–> Most DNA viruses replicate in the nucleus because they rely on the host cell’s DNA replication and transcription machinery, which is located in the nucleus. By replicating there, they can access the host’s DNA polymerases and transcription factors to make copies of their DNA and produce mRNA for protein synthesis.

Question 7

RNA viral replication presents special challenges because:

a) RNA viral codons differ from eukaryotic cells

b) RNA viral replication is not very efficient

c) RNA viral replication requires special polymerases not found in the cell

d) RNA viral genomes begin to degrade as soon as it enters the cell

Answer 7

c) RNA viral replication requires special polymerases not found in the cell.
–> Eukaryotic cells do not naturally have RNA-dependent RNA polymerases, which are required for RNA viruses to replicate their RNA genomes. RNA viruses must either bring their own RNA-dependent RNA polymerase into the host cell or encode it in their genome for immediate synthesis.

Question 8

A single virus-infected cell may produce up to __________ new virions.

a) 10
b) 1,000
c) 10,000
d) 100,000
e) 1,000,000

Answer 8

c) 10,000

(though chat gpt actually said 100,000)

Question 9

Retroviruses can lead to DNA mutations, but mRNA vaccines cannot. Why?

a) Retroviruses have DNA genomes that can recombine with ours

b) mRNA cannot get into the nucleus, but retroviral RNA can

c) Retroviruses carry a reverse transcriptase with them, that can copy RNA into DNA. Our cells do not have this enzyme

d) mRNA vaccines are quickly digested in the cytoplasm and do not have time to integrate into the genome

Answer 9

c) Retroviruses carry a reverse transcriptase with them, that can copy RNA into DNA. Our cells do not have this enzyme.

–> ^ Retroviruses have a special enzyme called reverse transcriptase. This enzyme allows the virus to reverse-transcribe its RNA genome into DNA once inside a host cell. This DNA is then integrated into the host’s genome, which can lead to mutations.
On the other hand, mRNA vaccines contain mRNA, but our cells do not have reverse transcriptase. As a result, the mRNA in vaccines cannot be converted into DNA and cannot integrate into the host genome.

Question 10

A fundamental difference between enveloped and non-enveloped mammalian viruses is:

a) enveloped viruses egress when the host cell lyses while non-enveloped viruses egress by budding off the host cell.

b) enveloped viruses egress by budding off the host cell while non-enveloped viruses egress when the host cell becomes unstable and lyses.

c) enveloped viruses egress by budding off the host cell while non-enveloped viruses egress by producing enzymes that degrade the host cell plasma membrane.

d)enveloped viruses egress by budding off the host cell while non-enveloped viruses infect other cells when the host cell divides.

Answer 10

b) enveloped viruses egress by budding off the host cell while non-enveloped viruses egress when the host cell becomes unstable and lyses.

Question 11

Which one of the following reinforces and stiffens membranes in bacteria?

a) hopanoids

b) polyamines

c) cholesterol

d) peptidoglycans

Answer 11

a) hopanoids
–> So, it’s eukaryotes that have cholesterol in their membranes to stiffen them. In prokaryotes, it’s hopanoids instead!

Question 12

All of the following are components of peptidoglycan EXCEPT

a) N-acetylglucosamine.

b) N-acetylmuramic acid.

c) lipopolysaccharide.

d) amino acids.

Answer 12

c) lipopolysaccharide.
–> Lipopolysaccharide (LPS), is a component of the outer membrane of Gram-negative bacteria, not part of the peptidoglycan structure.

——–Info on incorrect ones (so, ones that ARE part of peptidoglycan layer):

N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), which are sugars that form the backbone of the peptidoglycan structure.
Amino acids, which form the peptide cross-links between the sugar chains, providing structural strength.

Question 13

Besides the DNA residing in the nucleoid, two other kinds of DNA molecules that may be present in the cytoplasm of a bacterial cell are ________ and the genomes of ________.

a) exons; pseudogenes
b) introns; exons
c) plasmids; bacteriophages
d) pseudogenes; introns

Answer 13

c) plasmids; bacteriophages

Question 14

Which of the following statements about the prokaryotic flagella is INCORRECT?

a) It is driven by the cell’s transmembrane proton current.

b) It is embedded in the layers of the cell envelope.

c) It moves with a whip-like motion.

d) It is used for chemotaxis.

Answer 14

c) It moves with a whip-like motion.
–> It’s eukaryote flagella that move in whip-like motion. The bacteria ones rotate in a circle.

Question 15

In order for septation to occur, which process must finish first?

a) transcription and translation

b) membrane synthesis

c) DNA replication

d) cell wall synthesis

Answer 15

c) DNA replication
–> Septation is the process by which a bacterial cell divides into two daughter cells. Before septation can occur, the bacterial cell must replicate its DNA to ensure that each daughter cell receives a complete copy of the genome.
DNA replication must be completed first to ensure the cell has two copies of its genome, one for each daughter cell.

————- Info on incorrect ones:

a) Transcription and translation: These processes are ongoing during cell growth and division, but they are not the prerequisite for septation. They are important for producing the proteins needed for division but do not need to be completed before septation.

b) Membrane synthesis: Membrane synthesis is important for cell division, but it follows DNA replication and is not the primary limiting factor.

d) Cell wall synthesis: The cell wall is essential for the formation of the septum during division, but DNA replication must occur before septation to ensure that the newly formed daughter cells receive the full set of genetic material.

Question 16

The capsule polysaccharides form a slippery mucous layer that inhibits

a) phagocytosis
b) attachment
c) lysis
d) osmosis

Answer 16

a) phagocytosis
–> Capsules are thick, polysaccharide layers surrounding some bacteria. They help protect the bacteria from the host immune system by inhibiting phagocytosis—the process by which immune cells (like macrophages and neutrophils) engulf and destroy pathogens.
The slippery and smooth nature of the capsule prevents the immune cells from effectively grabbing onto and engulfing the bacteria, allowing the bacteria to evade the immune response.

————- Info on incorrect ones:

b) Attachment: The capsule can actually aid in attachment to surfaces, like host tissues, rather than inhibit it.

c) Lysis: While capsules can protect against immune attacks, they don’t directly prevent lysis, which is the breaking apart of cells.

d) Osmosis: The capsule doesn’t play a role in regulating osmotic pressure or preventing osmotic changes in the bacterial cell.

Question 17

INFO CARD: Okay, now we’re on Module 2.

Question 18

Bovine ________ not only make a significant contribution to global methane, they also divert carbon from meat production.

a) halophiles

b) methanogens

c) autotrophs

d) thermophiles

Answer 18

b) methanogens
–> Methanogens are a type of archaea that produce methane (CH₄) as a byproduct of their metabolism. They are commonly found in the digestive systems of ruminant animals like cattle (bovine). The methane produced by these microbes contributes significantly to global methane emissions. Additionally, the methane production process in these animals diverts some of the carbon that could otherwise be used for meat production, as the carbon is instead converted into methane.

Question 18

The use of oxygen as the terminal electron acceptor is called

a) aerobic respiration.

b) anaerobic respiration.

c) fermentation.

d) carbon dioxide fixation.

Answer 18

a) aerobic respiration.
–> This process occurs in organisms that require oxygen to generate ATP through oxidative phosphorylation.

Question 19

Which of the following are responsible for the CO2-fixation component of the carbon cycle?

a) heterotrophs

b) autotrophs

c) lithotrophs

d) organotrophs

Answer 19

b) autotrophs
–> Autotrophs are organisms that can produce their own food using inorganic substances. They are responsible for CO2 fixation in the carbon cycle, primarily through processes like photosynthesis (in plants, algae, and some bacteria) or chemosynthesis (in certain bacteria). In these processes, CO2 from the atmosphere is converted into organic molecules that can be used by the organism for growth and energy.

——–Info for incorrect ones:

a) Heterotrophs: These organisms cannot fix CO2; they rely on consuming organic molecules (like plants or other organisms) for carbon and energy.

c) Lithotrophs: These are organisms that use inorganic compounds (like hydrogen gas or sulfur) as their electron donors for energy, but they don’t directly fix CO2. Some lithotrophs are autotrophs and can fix CO2, but not all lithotrophs are involved in CO2 fixation.

d) Organotrophs: These organisms use organic compounds as their electron donors for energy but do not fix CO2. They rely on organic carbon from other sources.

Question 20

Which of the following substrates is an electron donor in organotrophy?

a) Fe2+

b) NO2

c) H2

d) Succinate

Answer 20

d) Succinate.
–> Organotrophy refers to the use of organic molecules as electron donors in metabolic processes. Succinate is an organic compound (a dicarboxylic acid) that donates electrons during cellular respiration, particularly in the tricarboxylic acid (TCA) cycle and electron transport chain.

—— Info on wrong ones:
a) Fe²⁺ (ferrous iron): This is an inorganic molecule, so its use as an electron donor falls under lithotrophy, not organotrophy.

b) NO₂⁻ (nitrite): This is also inorganic and acts as an electron donor in lithotrophic or chemolithoautotrophic processes.

c) H₂ (hydrogen gas): While H₂ is a common electron donor, it is inorganic and used in lithotrophy.

Question 21

A modest level of ethanol enters the human circulation naturally from ________; this is equivalent to a fraction of a drink per day.

a) intestinal microbiota byproducts

b) drink

c) cell metabolism

d) the environment

Answer 21

a) intestinal microbiota byproducts.
–> Intestinal microbiota byproducts: Certain gut microbes ferment carbohydrates and produce ethanol as a byproduct. This naturally occurring ethanol enters the bloodstream in very small amounts, equivalent to a fraction of a standard alcoholic drink per day.

—— Info about incorrect ones:

b) drink: This refers to external ethanol consumption, which is not “naturally” produced within the body.

c) cell metabolism: Human cells typically do not produce ethanol as a metabolic byproduct under normal conditions; instead, they produce energy through pathways like glycolysis and oxidative phosphorylation.

d) the environment: Ethanol absorption from environmental exposure (e.g., air or skin contact) is negligible compared to the ethanol generated internally by gut microbes.

Question 21

In bacteria, most active transport uses _________, but the ABC transporters use _____________.

a) Diffusion, ATP

b) the proton motive force, ATP

c) ATP, the proton motive force

d) Diffusion, the proton motive force

Answer 21

b) the proton motive force, ATP
–> Proton Motive Force (PMF): Most active transport in bacteria is powered by the proton motive force, an electrochemical gradient of protons across the bacterial membrane. This gradient drives transport proteins to move molecules like sugars, ions, and nutrients into or out of the cell.
ABC Transporters (ATP-Binding Cassette): Unlike other active transport mechanisms, ABC transporters utilize energy from ATP hydrolysis to transport substrates such as nutrients, toxins, or drugs across the membrane.

——- Info about wrong ones:

a) Diffusion, ATP: Diffusion is a passive process that does not require energy. Active transport is an energy-dependent process.

c) ATP, the proton motive force: Most active transport in bacteria uses PMF, not ATP, except for specific systems like ABC transporters.

d) Diffusion, the proton motive force: Again, diffusion is passive and does not involve energy sources like the proton motive force.

Question 22

In which phase would you expect to observe the most endospores in a Bacillus cell culture?

a) Log phase

b) Lag phase

c) Stationary phase

d) Death phase

Answer 22

d) death phase

–> In the death phase, nutrients are depleted, and waste products accumulate, causing many cells to die. However, some bacteria, like Bacillus, produce endospores as a survival mechanism under harsh conditions. The formation of endospores is a response to environmental stress, such as nutrient shortage or toxic build-up, and it happens when cells are near the end of their life cycle.
–> While endospores might start forming as the bacteria approach the stationary phase, where growth slows, they are most abundant during the death phase when conditions are most extreme, and the cells are trying to survive in adverse conditions.

Question 23

Which of the following statements about autoinducers is incorrect?

a) They bind directly to DNA to activate transcription.

b) They can activate the cell that secreted them.

c) N-acylated homoserine lactones are autoinducers in gram-negative cells.

d) Autoinducers may stimulate the production of virulence factors.

Answer 23

The incorrect statement is:
a) They bind directly to DNA to activate transcription.
–> Autoinducers are signaling molecules used in quorum sensing, a process that allows bacteria to regulate gene expression based on cell population density.
Autoinducers:
Do not bind directly to DNA. Instead, they typically bind to a receptor protein, which then acts as a transcriptional regulator to activate or repress gene expression.
Can activate the cell that secreted them. This is a hallmark of quorum sensing: bacteria respond to their own secreted signals.
N-acylated homoserine lactones (AHLs) are common autoinducers in gram-negative bacteria.
May stimulate the production of virulence factors when cell density reaches a critical threshold.

The others are all true.

Question 24

An inoculated culture tube shows dense growth at the surface and turbidity throughout the rest of the tube. What is your conclusion?

a) The organisms die in the presence of oxygen.

b) The organisms are facultative anaerobes.

c) The organisms should be grown in an anaerobic chamber.

d) The organisms are obligate aerobes.

Answer 24

b) The organisms are facultative anaerobes.
–> Facultative anaerobes can grow in the presence or absence of oxygen. They grow better at the surface, where oxygen is present, because they can use oxygen for more efficient aerobic respiration. However, they can also grow throughout the tube by switching to anaerobic respiration or fermentation when oxygen is not available.

——— Incorrect ones:
a) The organisms die in the presence of oxygen: This describes obligate anaerobes, which would not show any growth at the surface.

c) The organisms should be grown in an anaerobic chamber: This also refers to obligate anaerobes.

d) The organisms are obligate aerobes: Obligate aerobes grow only at the surface, where oxygen is available, and would not show turbidity throughout the tube.

Question 25

Bacteria isolated from Lake Natron, where the water pH is close to 10, are which of the following?

a) alkaliphiles

b) facultative anaerobes

c) neutrophiles

d) obligate anaerobes

Answer 25

a) alkaliphiles
—> Alkaliphiles are organisms that thrive in alkaline (basic) environments, such as those with a high pH like Lake Natron.

Question 26

An operon of genes encoding enzymes in a biosynthetic pathway is likely to be which of the following?

a) inducible

b) repressible

c) constitutive

d) monocistronic

Answer 26

b) repressible

Operons encoding enzymes in a biosynthetic pathway are typically repressible. In a repressible operon, the genes are usually expressed, but their expression is turned off when the end product of the biosynthetic pathway is abundant, thereby conserving energy and resources.

Question 27

Many bacteria produce some type of homoserine lactone for quorum sensing, yet some Gram-positive bacteria will produce ________ for this same purpose.

a) peptides

b) AHLs

c) cyclic di-GMP

d) ppGpp

Answer 27

a) peptides

–> While many Gram-negative bacteria use homoserine lactones (AHLs) for quorum sensing, Gram-positive bacteria typically use peptides as their signaling molecules for quorum sensing. These peptides can be secreted by the bacteria and then recognized by receptors on the same or nearby bacterial cells to regulate gene expression in response to population density.

Question 27

A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?

a) thermophiles

b) acidophiles

c) mesophiles

d) psychrotrophs

Answer 27

d) psychrotrophs

Psychrotrophs are microorganisms that can grow at low temperatures, such as those found in refrigerators. They can cause contamination in refrigerated food.

Question 28

Which of the following is a type of regulation of gene expression does NOT occur in bacteria?

a) attenuation

b) use of alternate σ factor

c) chemical modification of histones

d) riboswitches

Answer 28

c) chemical modification of histones

Chemical modification of histones is a mechanism of gene expression regulation that occurs in eukaryotes, not bacteria. In bacteria, histones are generally not involved in regulating gene expression.

Question 29

Microbes accumulate ________ in the cell to prevent cell water loss in a hypertonic environment.

a) water

b) sugars

c) protons

d) compatible solutes

Answer 29

d) compatible solutes

In a hypertonic environment, microbes accumulate compatible solutes (such as glycerol, betaine, or trehalose) in the cell to prevent water loss. These solutes help maintain cellular integrity and prevent dehydration without disrupting cellular functions.

Question 30

In the study of rapid adaptive evolution through exposure to the strongly selective environment of the addition of an antibiotic, the energy cost to an organism that emerges as the fittest is…

a) that its metabolic processes are slowed by the demands of the stress response.

b) a rapid growth rate as a result of increased DNA replication.

c) that its metabolic processes speed up as a result of increasing respiratory activities.

d) uncontrolled growth due to an inability to regulate mRNA translation.

Answer 30

a) that its metabolic processes are slowed by the demands of the stress response.

–> In the context of adaptive evolution in response to antibiotic stress, the energy cost to an organism that emerges as the fittest often involves slowing down its metabolic processes. This is because adapting to stressful environments (like the presence of antibiotics) typically requires additional energy for mechanisms such as stress response, repair, and maintaining cellular functions, which can slow down overall growth and metabolic processes.

Question 31

In the molecular control of chemotaxis, which statement below about CheA is TRUE.

a) CheA is activated when chemoattractant bind MCP

b) CheA is a response regulator

c) Activated CheA phosphorylates CheY and CheB

d) CheA is deactivated by CheR

Answer 31

c) Activated CheA phosphorylates CheY and CheB

–> CheA is a histidine kinase that plays a central role in the molecular control of bacterial chemotaxis. When CheA is activated (typically in response to the binding of a chemoattractant to a methyl-accepting chemotaxis protein, MCP), it phosphorylates the response regulators CheY and CheB. This phosphorylation allows these proteins to regulate the bacterial flagellar movement and the adaptation to the chemical signal.

Question 32

You add an inhibitor that blocks CheR activity then add a chemoattractant to the E.coli culture broth. What will happen to its chemotactic ability?

a) Decrease

b) Increase

c) No change

Answer 32

a) Decrease

–> CheR is responsible for methylating the MCPs (methyl-accepting chemotaxis proteins) in response to signals, which is important for the adaptation phase of chemotaxis. When CheR activity is blocked, the MCPs cannot be methylated properly, impairing the ability of the cell to adapt to a sustained presence of the chemoattractant. This means the bacterium will continue to respond to the chemoattractant, but it won’t be able to properly adapt or “turn off” its response. As a result, the bacteria will be less effective in their chemotactic behavior, leading to a decrease in their chemotactic ability.

Question 33

The stringent response involves all EXCEPT

a) the downregulation of rRNA synthesis.

b) the downregulation of tRNA synthesis.

c) increase in ATP synthase syntheses.

d) upregulation of critical biosynthetic operons.

Answer 33

c) increase in ATP synthase syntheses.

–> The stringent response is a regulatory mechanism in bacteria that occurs under stress conditions, such as nutrient deprivation or environmental stress. It involves the following:
*Downregulation of rRNA synthesis: To conserve resources under stress, bacteria reduce ribosome production.
Downregulation of tRNA synthesis: Similar to rRNA, tRNA synthesis is reduced to save resources.
*Upregulation of critical biosynthetic operons: The cell focuses on essential functions and survival processes under stress.
-> However, increase in ATP synthase synthesis is not part of the stringent response. The stringent response typically leads to a general slowdown in energy-intensive processes, not an increase in ATP production.

Question 34

What do you call adding an arsenic detoxifying bacteria to a new environment, with the goal of decontaminating the soil where it is added? Choose the best term.

a) Bioremediation

b) Bioaugmentation

c) Biostimulation

Answer 34

b) Bioaugmentation
–> Bioaugmentation refers to the process of adding specific strains of bacteria (or other microorganisms) to an environment to enhance the degradation of contaminants, such as arsenic, or to promote bioremediation. This process helps to decontaminate the soil or water by introducing microorganisms that can detoxify or break down pollutants more effectively.

—— Info on incorrect ones:

a) Bioremediation is the broader term that refers to the use of biological organisms, including bacteria, fungi, or plants, to remove or neutralize contaminants from the environment.

c) Biostimulation refers to the process of adding nutrients or other substances to the environment to stimulate the activity of existing microorganisms to degrade pollutants.

Question 35

________ is the growth of microorganisms not normally present within a host, without necessarily having an overt disease.

a) Septiceamia

b) Virulence

c) Infection

d) Pathogenicity

Answer 35

c) Infection
–> An infection refers to the growth and establishment of microorganisms, such as bacteria or viruses, in a host where they are not usually present. This does not always lead to disease; it simply means the microorganisms are present and potentially replicating.

—— Info on incorrect ones:

a) Septicemia: This refers to the presence and multiplication of pathogenic microorganisms in the blood, often leading to severe systemic infection or sepsis.

b) Virulence: This is a measure of a microorganism’s ability to cause disease, representing its degree of pathogenicity.

d) Pathogenicity: This is the ability of a microorganism to cause disease in a host. It’s a broader term describing whether or not an organism can be a pathogen.

Question 36

Which of these represent the first step towards pathogenesis?

a) Virulence

b) Adhesion

c) Invasion

d) Tissue damage

Answer 36

b) Adhesion
–> Adhesion is the first step in pathogenesis, where the pathogen attaches to the host’s cells or tissues using structures like pili, fimbriae, or adhesion proteins. Without adhesion, the pathogen cannot establish itself in the host to proceed with invasion, virulence expression, or causing tissue damage.

—– Info on incorrect ones:

a) Virulence: This refers to the severity or degree of a pathogen’s ability to cause disease, not a specific step.

c) Invasion: This occurs after adhesion, where the pathogen penetrates host tissues.

d) Tissue damage: This is a later stage caused by the pathogen’s toxins or immune system responses, not the first step.

Question 37

Note card: NOW we are on the MODULE 3 STUFF!

Question 38

Which of the following is not a virulence factor?

a) F plasmid

b) Resistance plasmid

c) Flagellum

d) Capsule

Answer 38

a) F plasmid
–> The F plasmid (fertility plasmid) is not considered a virulence factor because its primary role is in bacterial conjugation, not in causing disease.

——- Info on incorrect ones:

Resistance plasmid: this one creates antibiotic resistance, resistance plasmids indirectly contribute to virulence by making bacteria harder to treat, which can worsen infections.

Flagellum: Enables motility, which helps bacteria reach and colonize host tissues, an important step in pathogenesis.

Capsule: Protects bacteria from host immune responses, such as phagocytosis, aiding survival in the host.

Question 39

Name a category virulence factor that will help bacteria adhere to a cell or tissue.

Answer 39

adhesins.

Examples of Adhesins:

Fimbriae (Pili): Hair-like structures on the bacterial surface that attach to specific receptors on host cells.

Surface proteins: Such as M protein in Streptococcus or intimin in E. coli, which mediate tight adhesion.

Lipoteichoic acid (LTA): Found in Gram-positive bacteria, aiding adhesion to host tissues.

Question 40

Which are the most prevalent phyla in the gut microbiota?

a) Firmicutes

b) Proteobacteria

c) Bacteroidetes

d) Firmicutes, Bacteroidetes

e) Firmicutes, Bacteroidetes and Proteobacteria

Answer 40

d) Firmicutes, Bacteroidetes

or

e) Firmicutes, Bacteroidetes and Proteobacteria.

–> In the gut microbiota, Proteobacteria are present but are generally not as abundant as Firmicutes and Bacteroidetes. They are typically a minority group.

Question 41

Which tissue or organ has the LEAST amount of bacteria?

a) Lower lungs

b) Kidneys

c) Dry skin

d) Stomach

Answer 41

b) Kidneys
–> the kidneys are STERILE (or else you have an infection.)

Question 42

In mice and humans, which phyla is associated with obesity?

a) Bacteroidetes

b) Firmicutes

c) Methanogens

d) Bacteroidetes and Firmicutes

Answer 42

b) Firmicutes

Question 43

Which of these will NOT augment your chances of getting an infection?

a) Displacement of the commensal flora

b) A break in the epithelium

c) Eating raw food

d) Taking antibiotics

e) Colonic irrigation (colon cleansing)

f) Showering often

d) Heating up and eating a spaghetti portion that has been in the freezer for 5 months

Answer 43

f) Showering often

Question 44

At what age are humans considered to have their adult microbiota.

a) Shortly after birth

b) Around 3 years old

c) At adolescence

Answer 44

b) Around 3 years old

Question 45

Which of the following is NOT a character of our GI tract commensal flora?

a) It produces short-chain fatty acids

b) It can reside in the epithelial layer

c) It stimulates epithelial tight junctions function

d) It induces immune tolerance locally

e) It is a source of energy

Answer 45

b) It can reside in the epithelial layer
–> Commensal bacteria generally reside in the gut lumen or mucus layer, not within the epithelial cells, as this would trigger an immune response.

Question 46

Gene transfer from one bacterium to another by means of a bacteriophage is called _______, whereas _______ involves the transfer of DNA following cell-to-cell contact.

a) transformation; conjugation

b) transduction; conjugation

c) conjugation; transduction

d) transduction; transformation

Answer 46

b) transduction; conjugation

–> Transduction: This is the transfer of bacterial DNA from one bacterium to another via a bacteriophage (a virus that infects bacteria).
Conjugation: This is the transfer of DNA directly between two bacterial cells through cell-to-cell contact, often mediated by a structure called a pilus.

Question 47

Evolution toward pathogenicity may involve which of the following?

a) Horizontal gene transfer

b) Gene loss

c) Horizontal gene transfer and gene acquisition.

d) Horizontal gene transfer, gene loss, and gene acquisition.

Answer 47

d) Horizontal gene transfer, gene loss, and gene acquisition.

–> Any of these could lead to mutations that can cause the bacteria to become pathogenic.

Question 48

An example of vertical gene transfer is the

a) uptake of beta-lactamase genes by Streptococcus pneumoniae.

b) transfer of CRISPR spacers to daughter cells during cell division.

c) transfer of a plasmid from Agrobacterium to a plant.

d) transfer of conjugative plasmids from one strain to another.

Answer 48

b) transfer of CRISPR spacers to daughter cells during cell division.

–> Vertical gene transfer is passed down from generations

Question 49

A derivative F plasmid that contains host DNA is called an ________ plasmid.

a) F+

b) F-

c) Hrf

d) F’

Answer 49

d) F’
—> F’ plasmid: This is a derivative of the F plasmid that includes some bacterial chromosomal DNA. It occurs when the F plasmid excises imperfectly from the bacterial chromosome, taking some host DNA with it.

—-Info on incorrect ones:

a) F+: This refers to a bacterium with an F plasmid that does not contain host DNA. It can transfer the plasmid via conjugation.

b) F-: This refers to a bacterium without an F plasmid, unable to initiate conjugation.

c) Hfr: Stands for “high-frequency recombination” and refers to a cell where the F plasmid is integrated into the bacterial chromosome, enabling transfer of chromosomal genes during conjugation.

Question 50

Many infectious bacteria have regions of DNA coding for virulence factors. These regions are called

a) transposases.

b) F plasmids.

c) pathogenicity islands.

d) genome reductions.

Answer 50

c) pathogenicity islands.

Question 51

You’re done! Study the other ones now!