Microbiology Ch.8, 10, 13
In order to distinguish different strains of bacteria, an antibiogram relies on
differences in susceptibility to various antibiotics
A(n) ____ is a large segment of a cell's genome that has clearly originated in a different species
genomic island
In the soybean experiment, the ____ used more oxygen and the ____ used more ATP
germinating seeds; germinating seeds
X rays can cause which types of damage to a DNA molecule?
-Single stranded -Nucleobase alterations -Double stranded breaks
Which of the following statements about viruses are true?
-The viral capsid is composed of protein -Viruses contain DNA or RNA but not both
What is the purpose of a negative stain?
-To visualize a capsule (if present) -To visualize the bacteria -To determine morphological characteristics of the specimen
Enveloped viruses can derive their envelopes from
-certain host organelles -the host cytoplasmic membrane
MALDI-TOF mass spectrometry is an important new technology is bacterial identification because it can identify an organism from a colony
-rapidly, often in less than 15 minutes -based on the profile of its proteins
Encapsulated organisms are difficult to directly stain because
-the capsule does not react with most stains -the capsule is not permeable to stains
Specialized transduction
-transfers phage DNA and adjacent host genes -produces defective phage particles -results from errors in excision of the prophage
_____ is used to fix nucleotide incorporation errors that are missed by the proofreading function of DNA polyremase
Mismatch repair
Which are two main criteria used in classifying viruses?
Genome structure & Host range
What type of bacterial cell wall is composed of a think layer of peptidoglycan and an outer membrane?
Gram-negative
Neisseria gonorrhoeae
Gram-negative diplococci clustered in white blood cells in a urethral secretion from a man
Streptococcus pneumoniae
Gram-positive diplococci and white blood cells in a sputum sample
The oxygen utilized in cellular respiration finally shows up as
H2O
Select the possible hosts of prions
Humans, cattle, sheep, goats, deer, elk
During ____ recombination. a segment of DNA inserts into the cell's genome, a process that does not require a similar nucleotide sequence in the region of recombination
Non-homologous
Which of the following pairs is NOT paired correctly?
Nonsense mutation-- incorrect amino acid
Place the following taxonomic categories in the correct order from the largest (most inclusive) to the smallest, starting at the top
Phylum. Class, Order, Family, Specie, Genus
____ are the causative agents of transmissible spongiform encephalopathies
Prions
Replicases are ____ polymerases
RNA dependent RNA
Which of the following types of DNA repair does not requires the standard DNA polymerase with proofreading capabilites?
SOS repair
Bacteriophage DNA directs the synthesis of an enzyme which degrades the bacterial host cell's DNA?
True
T/F: Normal prion proteins can have the same amino acid sequence as the abnormal form of the protein
True
T/F: Scientists sort living organisms into different groups to show the relationships among the species
True
____ are a type of radiation that can cause single and double stranded breaks in a DNA strand
X rays
A Bacteriophage initially associates with which bacterial structure?
bacterial cell wall
Retroviruses may lead to latent infections because
they can integrate a DNA copy of their genome into the host chromosomes
Temperate phages are more likely to enter the lysogenic cycle when bacterial cells are __-
growing slowly
HIV infection
has features of both acute and persistent infection
The ______ assay involves serially diluting viral samples, mixing each dilution with red blood cells, and then determining the highest dilution that shows maximum clumping of the red blood cells.
hemagglutination
Following generalized transduction, DNA from the donor cell may be integrated into the recipient cell chromosome by _____ recombination.
homologous
The M13 phage has a single-stranded DNA genome. Its replicative form is a double-stranded DNA molecule. The second strand of DNA is synthesized by
host DNA polymerase
A bacterium spontaneously developing resistance to 2 different types of antibacterial medications is _____ it developing resistance to just one of them.
much less likely than
Gram ____ cell walls contain a thin layer of peptidoglycan whereas Gram ____ cell walls contain a thick layer of peptidoglycan.
negative; positive
In double stranded RNA viruses, the viral replicase uses the ___ strand of RNA to make ___ strands of RNA that can then be translated.
negative; positive
Once inside the host cell, viral DNA directs production of ____
new viral particles
A strain is
one of a group of related isolates within a species
Yeast cells under anaerobic
produce ethyl alcohol (ethanol)
Repair of nucleotide incorporation errors during the process of DNA replication is accompanied by ______ by DNA and by _____ repair
proofreading; mismatch
The genes that encode ribosomal RNA (rRNA) are
rDNAs
Missense mutation
results in changing a codon such that a different amino acid is specified
HIV is described as a ____ because it synthesizes DNA from RNA using reverse transcription to make a DNA copy from its RNA genome
retrovirus
Escherichia coli O157:H7 is an enterohemorrhagic stain responsible for many cases of foodborne illness. The O157: H7 refers to the antigenic type of its lipopolysaccharide (the O antigen) and flagella (the H antigen).E. Coli O157:H7 is therefore a _____ of E. COli
serotype or serovar
Signs of viral infections in plants include
stunted growth, yellowing of leaves, presence of tumors
Dr. Barbara McClintock determined that variegation in the color of corn kernels was due to the insertion of ____ elements into genes involved in pigment synthesis
transposable
Which of the following are replicons?
Plasmid Chromosome
Choose the correct descriptions of serological tests
-Require detection of antibodies -Rely on differences of surface structure molecules such as components of the cell wall, capsule, flagella, or pill.
Which of the following are systems bacteria can use to protect against invading DNA?
-Restriction modification -CRISPR
Which of the following processes will occur in the presence or absence of oxygen?
glycolysis
frameshit mutation
resulting from an insertion or deletion of bases that causes a change in the reading frame of the mRNA
Choose the properties that are responsible of members of eukarya
-Membrane bound nucleus -Introns -Cell membranes that contain fatty acids linked to glycerol by an ester linkage
Silent mutation
changes a codon into a different codon, but both codons specify the same amino acid; this causes no change in the resulting polypeptide
Restriction-modification systems of bacteria include what two components?
-Restriction enzyme that recognizes and cuts at a short nucleotide sequence -A Modification enzyme that adds protective methyl groups to the cell's own DNA
Which of the following are diseases caused by prions?
-Bovine spongiform encephalopathy -Creutzfeldt-Jakob disease -Scraple
Select the correct statements about cellular respiration
-Chemical energy in glucose is transformed to form of ATP -The overall equation for cellular respiration is C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36ATP -Glucose is oxidized completely to form carbon dioxide and water -The phases include glycolysis, the citric acid cycle, and the electron transport chain
Endospores are difficult to stain due to which of the following?
-Endospores exclude dye -Endospores have a thick spore coat.
Which of the following are examples of mobile genetic elements?
-Genomic islands, phage DNA, transposons, plasmids
Which of the following is the goal of phylogenic classification?
-Group organisms according to their evolutionary relatedness
Which of the following statements about prions are true?
-Infectious prion proteins are insoluble and aggregate in brain tissue -Infectious prion proteins can convert normal prion proteins into an abnormal function -Infectious prion proteins have a different shape from normal prion proteins
Which are the true statements about anaerobic respiration?
-Lactate may be produced -Ethanol may be produced -The reactions happen in the cytoplasm -CO2 is produced
Which of the following odds are within the range of mutation rates for a typical gene?
-One in ten thousand -One in one trillion -One in ten million -One in one billion
What are some difficulties in using phenotypic characterizations for the phylogenetic classification of prokaryotes?
-Phenotypically similar organisms may be only distantly related. -Organisms that appear dissimilar may be closely related -Phenotypic differences can be due to only a few gene products
`Which of the following are examples of physiological (biochemical) characteristics that could be used in the bacterial identification process?
-Presence of specific enzyme -Ability to break down lipids -Ability to ferment glucose
Place the descriptions of how CRISPR systems work in chronological order.
1. Cas protein complex cuts initial invading DNA into short fragments 2.Short DNA fragments are inserted into chromosomal region called CRISPR array 3.The cell transcribes the CRISPR array to produce small RNAs called cRNAs. 4.Each cRNA binds to a Cas nucleus 5.If cRNA base-pairs to invading DNA, Cas nuclease cuts the DNA
Place the steps of DNA-mediated transformation into the correct order.
1. Double stranded DNA molecule binds to surface receptor 2.Nucleases degrade one strand of double stranded DNA at the cell surface 3.Single stranded DNA enters cell after one strand has been degraded 4.Single stranded DNA integrates into genome after entering the cell 5.Strand being replaced by donor DNA is degraded
Place the following steps of the capsular stain in the proper sequence.
1. Place a drop of nigrosin on a clean slide 2.Add bacteria to nigrosin and mix 3.Spread the mixture over slide and air dry 4. Apply crystal violet 5.Rinse
Rank the following by size, from smallest to largest, starting with the smallest at the top.
1. Viruses 2. Bacteria 3. Human cells
Place the steps of the endospore stain in the correct sequence.
1.Apply malachite green to smear 2.Cover smear with small piece of paper towel 3.Stem over water bath 4.Rinse 5.Apply safranin to smear 6.Rinse and blot dry
Place the following steps of the acid-fast stain in the proper sequence.
1.Stain with carbolfuschin 2. Rinse off excess primary stain 3.Decolorize with acid alcohol 4.Rinse with water to stop the decolorization process. 5.Conuterstain with methylene blue 6.Rinse off excess counterstain 7. Blot dry
In taxonomy, the most useful rRNA molecule is the ____ in prokaryotes and the ____ rRNA in euakaroytes
16s; 18s
On which of the following DNA strands will UV light have the most effect?
ACTTGCTTAC
Which of the following genes are likely to be found on a plasmid rather than on the bacterial chromosome?
BT toxin gene, Chloramphenicol-resistance gene, Oil degradation enzyme genes,
Nonsense mutation
Changes a codon that specifies an amino acid to a stop codon, resulting in premature termination of polypeptide synthesis
During repair of oxidized guanine, DNA glycosylase removes the oxidized nucleobase, leading another enzyme to cut the DNA at this site. Which enzyme then degrades a short stretch of this DNA strand and synthesizes another strand with the proper nucleotides?
DNA ploymerase
What bacterial enzyme would the phage need to use to replicate their genome?
DNA polymerase
Phage typing relies on which of them following?
Differences in susceptibility of different stains of a given species of bacteria to bacteriophages
A bacteriophage can infect many different types (strains) of bacterial cells
False
Plant viruses and animal viruses enter their hosts cells after binding to receptors
False
T/F: Enveloped and non-enveloped viruses all mature fully in the cytoplasm of the host cell.
False
T/F: Enveloped viruses enter the host cell by endocytosis only, while non-enveloped viruses can enter the host cell by fusion or endocytosis
False
T/F: The 3-domain system has always been used as the standard classification system for organisms
False
T/F: Vertical gene transfer is the transfer of genes from one organism to another in a population, while horizontal gene transfer is the transfer of genes from parent cell to progeny.
False
T/F: Viroids contain a capsid but lack an envelope.
False
What would you predict would happen to the fermentation rate if you used yeast suspension that had not been swirled/ mixed each time before it was dispensed into the test tube?
The reaction would be very low
DNase is added to a mixture of donor DNA and recipient. If the donor DNA is naked, what will happen?
The recipient will be unable to acquire DNA via transformation
Which of the following statements bets describes mutation rates of genes?
They range between one in 10,000 and one in a trillion
Human cells are larger than viruses by which size factor?
Thousand
Replication of single-stranded DNA viruses is quite similar to that of double stranded DNA viruses, except that
a complement to the single stranded DNA molecule must be synthesized
Many bacteria are able to recognize and destroy invading DNA. It is thought this ability evolved ____.
as a defense against phages
In order to infect an animal cell, viruses must ____
attach to receptors on the host cytoplasmic membrane
In the Ames test, ____ are exposed to a possible carcinogen and are then plated onto ____ medium to test for reversion
auxotrophs; glucose-salts
If viruses are present in high enough concentrations in a sample, they can be quantified directly using a(n) ____ microscope
electron
Replication of double stranded DNA viruses
follows the central dogma of molecular biology
In quantal assays, the ID50 is the amount of pathogen that
infects half of a test population
In a quantal assay, LD50 is the amount of pathogen that
kills half of a test population
Type of anaerobic respiration include
lactic acid fermentation and alcoholic fermentation
A viral infection in which the viral genome is integrated into an animal host cell chromosome, yet can reactivate to cause a productive infection, is categorized as a(n) ____ infection
latent
The final step in T2 bacteriophage infection results in:
lysis of the bacterial cell and release of new viral particles
A ____ infection results in the integration of bacteriophage DNA into the chromosome of the bacterial host.
lysogenic
Plant viruses initially gain entry to host cells by ____
passing through wounds in the host cell walls
Unlike animal viruses that attach to specific receptors in order to gain entry into the cell, ____ viruses can gain entry into a cell through the damage in the cell wall.
plant
.After new virus particles have assembled in the bacterial host cell, they are usually
released as a result of host cell lysis
Plating bacteria in duplicate patterns on both a nutrient agar plate and a glucose-salt agar plate is an example of ____ plating.
replica
Neither strain A (His-/Trp-) nor strain B (Leu-/Thr-) can grow on minimal media on their own because they cannot synthesize the indicated amino acids/ If the strains are mixed ad then plated onto minimal media, any colonies that form
should be a result of horizontal gene transfer
Match the genome of each type of RNA virus with its description of function.
(+) strand genome: Serves as mRNA (-) strand genome: is the complement to mRNA Double-stranded genome: consists of both a(+) and (-) strand
Please match the statements about plasmid properties with the correct definition.
- Low copy number: Occur in one or a few copies per cell -High copy number: Occur in many copies in a cell -Narrow host range: Can replicate in only one species -Broad host range: Can replicate in many different species
Place in order the events that occur when performing phage typing
1.The test organism is inoculated into melted, cooled agar, which is then poured into an ager plate 2.Drops of different bacteriophages are spotted onto the agar surface 3.If the organism is susceptible to a specific phage, a clear area in the layer of host cells will form where the phage was placed 4. The pattern of clearing may be different for different bacterial strains and can be used for identification.
Which of the following scenarios would be least likely to require a nucleic acid amplification test?
A researcher trying to identify a flask of E. coli among a dozen mislabeled flasks of other microbes of medical importance growing in lab.
What is the best definition of a signature sequence?
A sequence in rRNA that characteristics either a certain species or a group of related organisms?
Which of the following is not a role played by NADH in cellular respiration?
A. It powers protons B. It transfers electrons C. It is involved in redox reactions D. It oxidizes pyruvate E. It accepts electrons and hydrogen ions D
You are attempting to identify an unknown bacterium by detecting nucleotide sequences. The bacterium could be one of seven different species of related groups. How many different probes do you need in order to identify their culture?
Seven
T/F: Viral particles can be shed from a host in feces, urine, genital secretions, blood, or mucus and saliva released from the respiratory tract during coughing or sneezing, allowing for transmission to a new host.
True
Regarding animal viruses, which of the following statements are true?
-Some viruses require more than one host receptor for attachment -Viruses use their spikes to attach to cell receptors -Blocking a host receptor with a drug would prevent a virus from infecting that cell
Which of the following are characteristics of recombinants?
-They result from horizontal gene transfer -They have properties of both donor and recipient cells
domain, kingdom, phylum, class, order, family, genus, species
...
Expression of viral oncogenes in infected animal cells
can mimic proto-oncogenes, causing imbalance in the cell cycle control towards unchecked proliferation, leading to tumor formation
Streptococcus pneumoniae is a bacterial pathogen that can cause pneumoniae. Lab studies of various subtype 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?
-S. Pneumoniae forming transparent colonies are lysogens -S. Pneumoniae bacteria containing MMI-1998 have a competitive advantage -Providing that the culture conditions of S. Pneumoniae are uncharged, subsequent generations of this bacteria will also exhibit change in the transparency and growth ability.
Which statements regarding viruses are true?
-Viruses that infect bacteria can be called phages -Viruses that infect bacteria can be called bacteriophages
Which of the following may benefit from the identification of specific microorganisms?
-Water quality analysis -Criminal investigations -Detection of bioterrorism attack
The study of viruses is important because ____
-bacteriophages play a significant ecological role in reducing bacterial populations in nature -there are many medically important viruses that cause disease -viruses can be a vehicle for horizontal gene transfer in bacteria
In RNA viruses that have a single strand (+) RNA genome, the viral genome
-can be translated to make proteins -is used as a template to make complementary (-) RNA strands that act as templates to produce more (+) RNA strands
According to the rules of nomenclature, the name of a bacterium or archaeon
-can honor a scientist -needs to include a Latin suffix -can reflect the habitat of the organism
In the case of retroviruses, reverse transcriptase uses a viral RNA template to synthesize DNA, which can then be
-transcribed and translated to form new virions -integrated into a host cell chromosomes where it remains latent