micro ch. 13-14 homework

Which of the following would NOT be considered virulence factor(s)? - Adhesins - Capsules - Endotoxins - Proteases - Ribosomes

Ribosomes

Transduction resulting from an error in excision of a prophage.

Specialized transduction

Label the parts of a typical enveloped virus particle. Not all labels are used.

Spikes: blue circles Matrix protein: the inside Envelope: the lining Capsid: the red casing thing Nucleic acid: the green spiraling thing Nucleocapsid: the capsid and the nucleic acid

Phage that is able to incorporate its genome into the host chromosome.

Temperate phage

A bacterium being examined in a microbiology laboratory is found to be lysogenized by phage A. Which of the following statements is TRUE?

The bacterium exhibits a new genotype but may not exhibit a new phenotype.

Please choose the statement that best describes the role of viral surface proteins or spikes. - Viral spikes inject viral nucleic acid into host cell. - Viral spikes enable replication of the viral nucleic acid. - Viral spikes allow viruses to bind to each other. - Viral spikes provide means for viruses to exchange nucleic acid. - Viral spikes provide means of attachment to host cell surface.

Viral spikes provide means of attachment to host cell surface.

Phage that lyses the bacterial host when completing its life cycle.

Virulent phage

Which of the following contains only one type of macromolecule? i. RNA viruses ii. DNA viruses iii. Prions iv. Viroids v. RNA and DNA viruses - (iii) and (iv) - (i), (ii), (iii), (iv), and (v) - (i), (iii), and (v) - (i) and (iv) - (ii) and (iii)

(iii) and (iv)

Select the ways that plant viruses can infect plants. CHECK ALL THAT APPLY. - By direct contact with specific receptors on plant cell cytoplasmic membranes. - By contact with intact and undisturbed plant cell wall structures. - By contaminated insects feeding on plant cells and disrupting the cell wall. - By soil that was previously used to grow infected plants. - Through grafting infected plant tissue onto healthy tissue.

- By contaminated insects feeding on plant cells and disrupting the cell wall. - Through grafting infected plant tissue onto healthy tissue.

You discover a new medication that prevents the activity of RNA-dependent RNA polymerase. Which of the following will be affected by this medication? CHECK ALL THAT APPLY. - Ebola virus - Herpes zoster virus - Human immunodeficiency virus - T4 phages - Polioviruses

- Ebola virus - Polioviruses

Which of the following statements about human papilloma virus (HPV) are TRUE? CHECK ALL THAT APPLY.

- HPV is more resistant to disinfectants than is herpes simplex virus - HPV may be carcinogenic. - A vaccine that protects against some dangerous strains of HPV is available.

Select all the TRUE statements about the benefits of normal microbiota. - Normal microbiota excludes pathogens in a variety of ways. - Normal microbiota stimulates the adaptive immune response. - Normal microbiota prevents the body from absorbing excess energy from foods. - Normal microbiota regularly produces substances detrimental to human health. - Normal microbiota plays a role in preventing an inappropriate immune response to harmless microbes.

- Normal microbiota excludes pathogens in a variety of ways. - Normal microbiota stimulates the adaptive immune response. - Normal microbiota plays a role in preventing an inappropriate immune response to harmless microbes.

Which of the following statements about plant virus transmission are TRUE? CHECK ALL THAT APPLY.

- Plant viruses enter their host through wounds - Grafted plants may be at risk of virus infection - An insect may transmit viruses between plants - Parasitic fungi may transmit plant viruses

Streptococcus pneumoniae is a bacterial pathogen that can cause pneumonia. Laboratory studies of various subtypes of this organism by The Rockefeller University scientists revealed that some of them produced colonies of different opacity (cloudiness). They found that compared with bacteria from opaque colonies, bacteria from more transparent colonies were found to grow more quickly and to adhere more efficiently to bronchial cells in culture. They also found that the bacteria from transparent colonies contained a phage strain called MM1-1998. Based on this information, which of the following statements are TRUE? CHECK ALL THAT APPLY. - S. pneumoniae forming transparent colonies are lysogens. - S. pneumoniae bacteria containing MM1-1998 have a competitive advantage. - MM1-1998 affected genotype but not phenotype of the S. pneumoniae. - Lysogenized S. pneumoniae is immune to infection by other strains of MM1. - Providing that the culture conditions of the S. pneumoniae are unchanged, subsequent generations of this bacterium will also exhibit change in transparency and growth ability.

- S. pneumoniae forming transparent colonies are lysogens. - S. pneumoniae bacteria containing MM1-1998 have a competitive advantage. - Providing that the culture conditions of the S. pneumoniae are unchanged, subsequent generations of this bacterium will also exhibit change in transparency and growth ability.

Bacteriophage MS2 is an icosahedral, (+) sense, single-stranded RNA phage. It infects E. coli and other members of the Enterobacteriaceae. It only infects strains of these bacteria that have produced a sex pilus. Based on the information given, which of the following are true about MS2? - The bacterial receptor for MS2 is on the F (sex) pilus. - MS2 is a virulent phage. - MS2 is a temperate phage. - The phage carries a replicase. - MS2 carries a DNA polymerase. - MS2 can only infect F+ bacteria.

- The bacterial receptor for MS2 is on the F (sex) pilus. - MS2 is a virulent phage. - The phage carries a replicase. - MS2 can only infect F+ bacteria.

Identify all the characteristics that are associated with type III secretion systems. - Found only in Gram-positive bacteria. - Look like small molecular syringes that inject bacterial compounds into a cell. - Look like complex export pumps that send bacterial compounds into the external environment. - Cells will either have type III secretion systems or a cell wall, but not both. - The proteins transported by a type III secretion system are made by a host cell and delivered to a bacterial cell. - The proteins transported by a type III secretion system are made by a bacterial cell and delivered to a host cell.

- The proteins transported by a type III secretion system are made by a bacterial cell and delivered to a host cell. - Look like small molecular syringes that inject bacterial compounds into a cell.

Select the TRUE statements regarding reverse-transcribing viruses. CHECK ALL THAT APPLY. - They have a unique enzyme called reverse transcriptase. - Their replication strategy goes against the central dogma of genetics. - They have both RNA and DNA.They have both RNA and DNA. - They exhibit high mutation rates in their genomes. - They infect primarily bacteria.

- They have a unique enzyme called reverse transcriptase. - Their replication strategy goes against the central dogma of genetics. - They exhibit high mutation rates in their genomes.

Which of the following characteristics can be utilized to classify and categorize viruses? CHECK ALL THAT APPLY. - Type of nucleic acid - Hosts infected - Strandedness of nucleic acid (positive/negative sense) - Capsid shape - Gram stain category - Colony growth characteristics - Presence or absence of capsule - Presence or absence of envelope - Disease symptoms - Fermentation of different sugars

- Type of nucleic acid - Hosts infected - Strandedness of nucleic acid (positive/negative sense) - Capsid shape - Presence or absence of envelope - Disease symptoms

Select the possible hosts of prions. - plants - bacteria - humans - cattle - sheep - goats - deer - elk

- humans - cattle - sheep - goats - deer - elk

Please order the following steps to reflect the order in which they occur in the replication cycle of an animal virus.

1: Adsorption (attachment) to host cell surface 2: Penetration and uncoating 3: Synthesis of viral nucleic acid and proteins 4: Assembly of viral particle 5: Release from host cell

In a bacteriophage plaque assay, the following steps are taken to enumerate phage particles. Place the steps in the correct order.

1: Regular bacterial growth plates are prepared. 2: Dilutions of viral samples is prepared. 3: Host bacteria and dilution of viral sample are mixed in liquid soft-agar. 4: Mixture is poured on top of plate and allowed to harden. 5: Plates are incubated overnight. 6: Circular zones of clearing in bacterial growth are observed and counted. 7: Number of zones of clearing multiplied by the inverse of the dilution factor to get PFUs/milliliter in original sample.

Please place the steps for animal virus replication in the correct sequence:

1: Virus attaches to receptors on the host cell cytoplasmic membrane. 2: Virus enters the host cell by fusion or endocytosis. 3: Viral genome is uncoated. 4: Structural and catalytic viral genes are expressed. 5: Multiple copies of the viral genome are synthesized. 6: New viral particles assemble and mature. 7: Viruses are released from the host cell by budding or during apoptosis of the host cell.

Select the correct sequence for proving Koch's postulates: 1. The microorganism must be recovered from the experimentally infected hosts. 2. The microorganism must be present in every case of the disease. 3. The same disease must be produced when a pure culture of the microorganism is introduced into susceptible hosts. 4. The microorganism must be grown in pure culture from diseased hosts.

2,4,3,1

Infection in which a virus multiplies rapidly and spreads in the host.

Acute infection

Please select the CORRECT definition regarding interactions between hosts and microbes. - Dysbiosis—an imbalance in the microbiome that may be caused by taking antimicrobial medications. - Parasitism—relationship between two organisms in which one partner benefits and the other is unaffected. - Immunocompetent—having a weakness or defect in the innate or adaptive defenses. - Fc receptors—molecule that binds the antigen-binding region of an antibody. - Secondary infection—infection in a previously healthy person, such as measles in a child who has not had measles before.

Dysbiosis—an imbalance in the microbiome that may be caused by taking antimicrobial medications.

T/F: Prion replication depends on the presence of a protease.

False

Transduction resulting from a packaging error.

Generalized transduction

Influenza vaccines must be changed yearly because the viral antigens change from year to year. Based on this information, which of the following is most likely true about the influenza virus? - It is a non-enveloped virus. - It has a DNA genome. - It is an enveloped virus. - It has an RNA genome. - It causes a persistent infection.

It has an RNA genome.

Which of the following about viruses/viral infections is FALSE? - The virus that causes chickenpox can establish a latent infection. - Viruses are generally not considered to be "alive." - Phages often enter a cell via receptor-mediated endocytosis. - The virus that causes genital herpes can establish a latent infection. - Animal viruses often enter a cell via receptor-mediated endocytosis.

Phages often enter a cell via receptor-mediated endocytosis.

A number of viruses often include a similar set of symptoms when they cause an infectious disease state (fever, headache, fatigue, runny nose). Why would they all cause the same symptoms if they're different viruses?

The symptoms are associated with the immune system's response, NOT the molecules from the pathogens themselves. Our responses against viruses are fairly similar, regardless of virus type, so the symptoms are similar.

Would an antibody response against the B subunit of an A-B toxin protect against the effects of the toxin? - Yes. If antibodies bind to the B portion, the toxin can no longer bind to target cells and will thus not affect those cells. - No. Even if antibodies bind to the B portion of the toxin, the toxin is still taken into the host cell by phagocytosis, damaging that cell. - This question cannot be answered. The immune system does not mount a strong response against proteins, so this situation is unlikely to occur. - Yes. If antibodies bind to the B portion, that portion of the toxin does not become activated, and thus does not damage the host cell. - No. Even if antibodies bind to the B portion of the toxin, it is the A portion that actually causes damage to the cell.

Yes. If antibodies bind to the B portion, the toxin can no longer bind to target cells and will thus not affect those cells.

A patient is suffering from a severe case of influenza, caused by influenza virus. He takes analgesics (painkillers) and also a fever-reducing medication, and after a few days begins to feel better. However, just as he thinks he will be able to return to school, the patient suddenly worsens, developing chest pain, and a productive cough (coughing up sputum). When he notices that his sputum contains blood, he goes to the doctor who diagnoses pneumonia, caused by the bacterium Streptococcus pneumoniae. In this scenario, the influenza virus is ______ while the S. pneumoniae is _______. - an opportunistic pathogen; a primary pathogen - normal microbiota; normal microbiota - a primary pathogen; an opportunistic pathogen - a primary pathogen; normal microbiota - normal microbiota; a primary pathogen

a primary pathogen; an opportunistic pathogen

Influenza viruses bud from the host cell. Based on this information, the viruses most likely: -have an RNA genome - are enveloped - have a latent state - are non-enveloped - form a pro virus - have a DNA genome

are enveloped

A microbiologist discovers a new infectious agent. In an effort to identify the type of agent, the microbiologist exposes the agent to the following: i. RNAse ii. DNAse iii. Protease iv. Heat v. Acid After the different treatments, the microbiologist determines that the agent is destroyed by treatments (i), (iv), or (v). This result leads the scientist to conclude that the agent likely is a(n)

viroid