MicroBiology Test 2

Which of the following is not associated with the DNA helix? A. Complementary base pairing B. Amino acids C. Phosphodiester bonds D. Thymine

B. Amino acids

A patient infected with a multidrug-resistant strain of Mycobacterium tuberculosis would be cared for in a __________ facility. A. BSL-4 B. BSL-3 C. BSL-2 D. BSL-1

B. BSL-3

Nucleic acid detection techniques: A. are used to culture animal viruses in the lab. B. can detect new viruses and early-stage infections that antibody-antigen tests are likely to miss. C. are less sensitive than the antigen-antibody-based tests. D. are much slower than the antigen-antibody-based tests.

B. Can detect new viruses and early-stage infections that antibody-antigen tests are likely to miss

The protein shell that packages and protects the genome and also accounts for the bulk of a virion's mass is called a __________. A. tail fiber B. capsid C. envelope D. capsomere

B. Capsid

Which of the following statements about DNA is incorrect? A. DNA has an antiparallel arrangement. B. DNA is a long, single-stranded molecule that curves into a helix, and the set pairings of the bases ensure that there is always a purine across from another purine and a pyrimidine across from another pyrimidine. C. The alternating sugars and phosphate molecules of the DNA backbone bond together via phosphodiester bonds. D. The nitrogen base adenine always pairs with thymine, and guanine always pairs with cytosine.

B. DNA is a long, single-stranded molecule that curves into a helix, and the set pairings of the bases ensure that there is always a purine across from another purine and a pyrimidine across from another pyrimidine.

Which of the following statements about DNA replication in bacteria is false? A. The leading strand is made continuously. B. DNA replication proceeds in only one direction around a circular chromosome. C. DNA replication is semiconservative. D. DNA polymerase can only proceed in a 5' to 3' direction.

B. DNA replication proceeds in only one direction around a circular chromosome.

The most common drugs that block replication are __________. A. interferons B. nucleoside analogs C. protease inhibitors D. nucleoside reverse transcriptase inhibitors (NRTIs)

B. Nucleoside Analogs

Which of the following is not part of the five general steps that a microbe must follow in order to successfully establish an infection? A. Adhere to host tissues B. Release endotoxins C. Replicate while warding off immune defenses D. Transmit to new host

B. Release endotoxins

Which of the following statements is false concerning RNA? A. In RNA, the nitrogen base thymine is replaced by uracil. B. Ribonucleotides found in RNA include the same sugar deoxyribose that is found in DNA. C. Cells make numerous types of RNA. D. RNA is a single-stranded molecule.

B. Ribonucleotides found in RNA include the same sugar deoxyribose that is found in DNA.

Why are you supposed to get a new flu shot every year? A. Influenza viruses may undergo a major genetic reassortment that dramatically changes HA and NA spikes, called antigenic shift. B. The RNA genome of influenza mutates frequently, causing minor changes; This is referred to as antigenic drift. C. The flu vaccine confers lifelong immunity. D. The vaccine composition is not altered from year to year.

B. The RNA genome of influenza mutates frequently, causing minor changes; this is referred to as antigenic drift.

Which of the following is not a property used to group viruses? A. Presence or absence of an envelope B. Unicellularity versus multicellularity C. Type of nucleic acid present (DNA or RNA) D. Capsid symmetry (helical, icosahedral, or complex)

B. Unicellularity versus multicellularity

Viruses do not infect which of the following organisms? A. Fungi B. Viruses can infect all forms of life. C. Bacteria D. Animals

B. Viruses can infect all forms of life.

You are testing a chemical that you suspect is a mutagen. You set up an AMES test, and for your control (without the mutagen added to the bacterial culture) you observed only a few colonies. After you added the mutagen to the test sample, you observed similar results to your control—only a few colonies grew. What can you conclude about the chemical? A. Your chemical is mutagenic. B. Your chemical is not mutagenic. C. Your test did not work. D. You should have used a different test than the AMES test to check whether your chemical is mutagenic.

B. Your chemical is not mutagenic.

Upon entering the host, the pathogen may conceal antigenic features so the immune system doesn't quickly mount an attack. This is also known as __________. A. antigen variation B. antigen masking C. antigens D. antigen mimicry

B. antigen masking

Cytopathic effects induced by a virus include __________. A. releasing toxins B. hijacking cellular machinery and disrupting normal host cell function C. invading host cells D. exploiting host nutrients

B. hijacking cellular machinery and disrupting normal host cell function

An operon that is transcribed in response to the presence of a substrate is called a(n) _______. A. repressible operon B. inducible operon C. constitutive operon D. promoter

B. inducible operon

Microbes transferred via the __________ portal of exit(s) would be present in pus or drainage that is easily transmitted to others. A. GI mucosa B. otic and skin C. ocular D. urogenital

B. otic and skin

Which of the following suffixes would be used to describe a viral family? A. -virales B. -virus C. -viridae D. -virinae

C. -Viridae

Spontaneous mutations are estimated to occur in one out of every __________ base pairs. A. 10^7 (10 million) B. 10^6 (1 million) C. 10^10 (10 billion) D. 10^8 (100 million)

C. 10^10 (10 billion)

A healthy gut microbiome contains diverse species where benign microbes help keep pathogenic members in check. Which of the following could tip the balance from normal microbiota to a disease state? A. Presence of Group B streptococci in a female's vagina B. Presence of Escherichia coli in the gut C. A patient on an intravenous course of antibiotics D. Presence of Staphylococcus epidermidis on the skin

C. A patient on an intravenous course of antibiotics

In a(n) __________ infection, viral replication peaks, followed by immune clearance of the virus. A. persistent B. chronic C. acute D. latent

C. Acute

Which of the following is a major difference between bacteriophages and animal viruses? A. There are no differences between animal viruses and bacteriophages. B. Animal viruses are assembled in the cytoplasm of cells; bacteriophages are assembled in the nucleus of a bacterial cell. C. Animal viruses enter the host cell; bacteriophages inject their genome into the host without entering. D. Animal viruses are only released from the host cell by cellular lysis; bacteriophages are released by budding.

C. Animal viruses enter the host cell; bacteriophages inject their genome into the host without entering.

Which of the following would be an example of a chemical mutagen? A. Transposons B. X-rays C. Arsenic D. UV radiation

C. Arsenic

Bacteriophages use different mechanisms for host cell infection and viral replication. During the lytic replication pathway, bacteriophages infect the host bacterial cells and immediately build new virions. During which of the key steps is the genome packed into the capsid and phage structures put together? A. Penetration B. Release C. Assembly D. Replication

C. Assembly

Which of the following steps is found in the lysogenic replication pathway but not in the lytic replication pathway? A. Assembly B. Penetration C. Integration D. Attachment

C. Integration

Which of the following conditions would allow for the active transcription of the lac operon? A. The lac operon is transcribed constitutively. B. Lactose present, glucose present C. Lactose present, glucose absent D. Lactose absent, glucose present

C. Lactose present, glucose absent

A new type of fungal meningitis (infection of the nervous system) was discovered. Disease occurred among patients who had received steroid injections into their spine. What was the portal of entry? A. Urogenital B. Otic C. Parenteral D. Transplacental

C. Parenteral

Which of the following body sites would least likely contain a biofilm? A. Teeth B. Urethra with urinary catheter C. Placenta D. Hip with artificial joint

C. Placenta

Which of the following would not be a component of an operon? A. Operator B. Promoter C. Start codon D. Structural genes

C. Start codon

Transposons, also known as "jumping genes," can have a wide-range effect on cells. Which of the following would not likely be an effect? A. Transposons may change genetic sequences. B. Transposons may alter gene expression patterns. C. Transposons can repair damaged DNA. D. Transposons may introduce new genes.

C. Transposons can repair damaged DNA.

Exotoxins are often classified into three main families based on their mode of action. Which of the following pairs is correctly matched? A. Type III - extracellular toxin B. Type II - membrane-acting toxins C. Type III - intracellular toxin D. Type I - membrane-damaging toxins

C. Type III - intracellular toxin

Bacterial capsules __________. A. can block the fusion of lysosomes with the phagosome B. allow for cells to live in phagocytic cells C. allow for avoidance of phagocytosis D. release toxins that kill phagocytes

C. allow for avoidance of phagocytosis

Botulism is caused by ingesting __________. A. acid-fast organisms B. Gram-negative organisms C. exotoxins D. endotoxins

C. exotoxins

The preference of a pathogen for a specific host is also known as ___________. A. pathogenicity B. virulence C. tropism D. attenuation

C. tropism

Which of the following oncogenic (cause cancer) viruses may integrate into the host genome? 1. Human T-lymphotropic viruses (HTLVs) 2. Hepatitis B virus 3. Human herpes virus-8 (HHV-8) 4. Hepatitis C virus 5. Epstein-Barr virus 6. Human papillomaviruses (HPVs)

1. HTLVs 6. HPVs

Which of the following statements are true about SARS-CoV-2? 1. The genome of SARS-CoV-2 undergoes mutations. 2. The strain designation of SARS-CoV-2 is H1N1. 3. SARS-CoV-2 causes Covid-19. 4. The virus attaches to host cells via its neuraminidase spike. 5. SARS-CoV-2 is a naked virus. 6. SARS-CoV-2 has an antisense RNA genome.

1. The genome of SARS-CoV-2 undergoes mutations. 3. SARS-CoV-2 causes Covid-19

Prokaryotes and eukaryotes differ in how they accomplish transcription and translation. Which of the following are unique to prokaryotic cells? 1. Messenger RNA must travel out of the nucleus to reach a ribosome for translation. 2. Translation of an RNA sequence can begin before transcription is complete. 3. The main enzyme is RNA polymerase. 4. Uses a lot of cellular energy. 5. RNA must be spliced after it is transcribed before it can be translated. 6. Transcription occurs in the cytoplasm.

2. Translation of an RNA sequence can begin before transcription is complete. 6. Transcription occurs in the cytoplasm.

Choose all of the following that are virulence factors. 1. Plasma membrane 2. Peroxisomes 3. Adhesins 4. Ribosomes 5. Exotoxins 6. Lysosomes

3. Adhesins 5. Exotoxins

The central dogma states that the primary flow of "genetic information" in a cell primarily proceeds from __________. 1. DNA to protein to RNA 2. RNA to DNA to protein 3. protein to RNA to DNA 4. DNA to RNA to protein

4. DNA to RNA to protein

Which of the following scenarios are examples of an opportunistic pathogen causing infection? 1. Streptococcus pyogenes causing strep throat or pharyngitis 2. Shigella dysenteriae causing diarrhea and dysentery following ingestion 3. Mycobacterium tuberculosis causing tuberculosis following respiratory exposure 4. E. coli from the appendix entering the peritoneum and causing infection 5. Bacillus anthracis causing anthrax following exposure 6. Candida albicans causing thrush after treatment with antibiotics

4. E. coli from the appendix entering the peritoneum and causing infection 6. Candida albicans causing thrush after treatment with antibiotics

Post-transcriptional regulation allows cells to control gene expression by regulating how often mRNA is translated into protein. Which of the following is not an example of post-transcriptional regulation? 1. Riboswitches 2. Controlling mRNA stability 3. Small non-coding RNAs 4. Operons

4. Operons

Cells can only contain which of the following types of genomes? A. A double-stranded DNA genome B. A single-stranded RNA genome C. A single-stranded DNA genome D. A double-stranded RNA genome

A. A double-stranded DNA genome

Most hospitals and microbiology teaching laboratories maintain __________ standards. A. BSL-2 B. BSL-4 C. BSL-1 D. BSL-3

A. BSL-2

.Which of the following methods is used to cultivate bacteriophages in the laboratory setting? A. Bacteriophages are cultivated in bacteria in liquid broth or on a solid medium. B. Bacteriophages are cultivated in embryonated eggs. C. Bacteriophages are cultivated in tissue cultures. D. Bacteriophages are grown with the streak plate method.

A. Bacteriophages are cultivated in bacteria in liquid broth or on a solid medium.

Which type of invasin is correctly matched with a representative organism? A. Coagulase - Staphylococcus aureus B. Kinase - Vibrio cholerae C. Collagenase - Streptococcus pyogenes D. Neuraminidase - Escherichia coli

A. Coagulase - Staphylococcus aureus

Which of the following terms is used to describe the shape of a virus? A. Icosahedral B. Bacillus C. Coccus D. Spirillum

A. Icosahedral

Which type of method is used to determine if a prior exposure to a virus occurred? A. Latex agglutination test B. Plaque assay C. Tissue culture D. Gram staining

A. Latex Agglutination Test

If a wild-type DNA sequence reads AAA ACG CCG AGG, what type of mutation would change it to AAA ACC CCG AGG? A. Missense B. Deletion C. Frameshift D. Insertion

A. Missense

Which of the following enzymes is incorrectly matched with its function? A. Polymerase I: copies DNA on the leading and lagging strands B. Helicase: unwinds DNA helix C. Primase: lays down RNA primers D. Ligase: forms phosphodiester bonds to seal nicks in the DNA backbone in the lagging strand

A. Polymerase I: copies DNA on the leading and lagging strands

Which of the following acellular agents do not have any genetic material and therefore do not replicate? A. Prions B. Protists C. Archaea D. Bacteria

A. Prions

Which of the following is not needed during transcription? A. Ribosomes B. RNA polymerase C. Ribonucleotides D. DNA template

A. Ribosomes

Which of the following correctly describes infectious dose-50 (ID50)? A. The more infectious the pathogen is, the lower the ID50. B. ID50 describes the amount of toxin needed to kill 50 percent of affected hosts that are not treated. C. The lethality of an infectious agent is usually expressed as mortality rate, rather than as ID50. D. The more infectious the pathogen is, the higher the ID50.

A. The more infectious the pathogen is, the lower the ID50.

Which term is incorrectly matched with the provided definition? A. Transduction: introduction of new genetic material into a viral cell by a bacterial species B. Transposons: movable genetic elements that are also known as "jumping genes" C. Conjugation: transfer of genetic material via a pilus D. Transformation: uptake of DNA from the environment

A. Transduction: introduction of new genetic material into a viral cell by a bacterial species

You attended a BBQ and ate a variety of foods, including potato and egg salads. After you arrive home a few hours later, you display symptoms of food poisoning (vomiting, diarrhea, cold sweats, etc). Which type of exotoxin did you likely ingest? A. Type I B. Type II C. Type IV D. Type III

A. Type I

Messenger RNA (mRNA) __________. A. is translated to build proteins B. combines with proteins to build ribosomes C. contains deoxyribose D. serves as a molecule to carry amino acids to the ribosome during translation

A. is translated to build proteins

Which of the following is the product of transcription? A. Multiple Okazaki fragments B. A polypeptide sequence C. A newly replicated strand of DNA D. An RNA sequence

D. An RNA sequence

Which of the following is not a mechanism of an antiviral drug? A. Blocking uncoating B. Blocking viral attachment C. Blocking viral penetration D. Blocking viral ribosomes

D. Blocking Viral Ribosomes

Which of the following statements are incorrect about the transmission of Creutzfeldt-Jakob disease? A. Iatrogenic transmission can occur through contaminated surgical instruments. B. In the past, cases of CJD were transmitted through treatment with human growth hormone harvested from cadaver pituitary tissue. C. CJD can be acquired through a dura mater graft used to treat traumatic head injury. D. Creutzfeldt-Jakob disease can be transmitted through respiratory droplets. E. Creutzfeldt-Jakob disease is never inherited.

D. Creutzfeldt-Jakob disease can be transmitted through respiratory droplets. E. Creutzfeldt-Jakob disease is never inherited.

How would Pseudomonas aeruginosa most likely adhere to the respiratory membrane of a patient on a ventilator? A. Heparin sulfate binding factors B. Fibronectin binding factors C. Sialic acid binding factors D. Fimbriae

D. Fimbriae

Which of the following statements correctly describes endotoxins? A. Endotoxins have a relatively low LD50. B. Endotoxins are released from actively dividing bacteria. C. Both Gram-positive and Gram-negative bacteria produce endotoxins. D. Gram-negative bacteria mainly release endotoxin when they die, although a small amount can be released as the bacteria divide.

D. Gram-negative bacteria mainly release endotoxin when they die, although a small amount can be released as the bacteria divide.

Which of the following statements incorrectly describes viral spikes? A. Spikes have an important role in determining what species and tissues the virus can infect. B. Spikes are glycoprotein extensions that help viruses attach and gain entry to host cells. C. Spikes may be recognized by the host immune system that mounts an immune response to them. D. Lipid-based spikes make up the envelope that surrounds the capsid.

D. Lipid-based spikes make up the envelope

Which of the following statements is false concerning RNA? A. In RNA, the nitrogen base thymine is replaced by uracil. B. Cells make numerous types of RNA. C. RNA is a single-stranded molecule. D. Ribonucleotides found in RNA include the same sugar deoxyribose that is found in DNA.

D. Ribonucleotides found in RNA include the same sugar deoxyribose that is found in DNA.

Which of the following would be the best general description of a "virus"? A. Viruses are cells without a nucleus or other membrane-bound organelles. B. Viruses are cells with a nucleus and membrane-bound organelles. C. Viruses are acellular infectious agents with DNA genomes. D. Viruses are acellular infectious agents.

D. Viruses are acellular infectious agents.

Your patient is suffering from severe diarrhea caused by a Clostridioides difficile infection. Which of the following would be a special type of contact precaution to prevent the spread of the organisms? A. Place patient in airborne infection isolation room (AIIR) facility. B. Wash hands at all times. C. Limit patient transport. D. Wear a barrier gown at all times.

D. Wear a barrier gown at all times.

Used in conjunction with standard precautions, __________ are used to reduce the spread of an agent that is communicated through large moist respiratory droplets that do not remain suspended in the air and therefore require closer contact for transmission. A. contact precautions B. standard precautions C. airborne precautions D. droplet precautions

D. droplet precautions

In an operon, the repressor binds to the _______. A. promoter B. genes C. inducer D. operator

D. operator

You are observing the cell shape of an unknown bacterial organism that you isolated from a patient using a microscope. Thus, you are studying its __________. A. genome B. genotype C. plasmids D. phenotype

D. phenotype

Which of the following viral genomes is immediately ready for translation after the virus gains entry into the cell? A. ssDNA B. dsDNA C. dsRNA D. ssRNA+

D. ssRNA+