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157 terms

EW Test 2

STUDY
PLAY
A gene is best defined as
a sequence of nucleotides in DNA that codes for a functional product.
DNA is constructed of
two strands of nucleotides running antiparallel.
Transformation is the transfer of DNA from a donor to a recipient cell
as naked DNA in solution.
Genetic change in bacteria can be brought about by
mutation conjugation transduction transformation.
An enzyme that copies DNA to make a molecule of RNA is
RNA polymerase.
An enzyme that catalyzes the cutting and resealing of DNA, and is translated from insertion sequences, is
transposase
True or False Bacteria typically contain multiple chromosomes.
Flase
What are the products of semiconservative replication for a double-stranded DNA molecule?
Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.
What is the function of the parental DNA in replication?
It serves as the template for DNA replication.
What is considered to be the average natural mutation rate that occurs during DNA replication?
One in every billion nucleotides replicated.
A mutation that affects the genotype of the organism but not the phenotype is called a
silent mutation.
A base insertion or deletion in the translated region of the gene may lead to
frameshift mutation.
A base substitution that changes a codon coding for an amino acid to a stop codon is called a
nonsense mutation
How frequently do silent mutations occur?
One out of every three mutations
Bacterial conjugation is often referred to as bacterial sex. Why is this term inaccurate?
Conjugation does not result in the formation of new offspring.
What must occur for bacterial conjugation to take place?
The cells must come into contact with each other.
Which statement about conjugation is false?
Conjugation is a process of bacterial reproduction.
Based on the animation, what is transferred during bacterial conjugation?
A bacterial plasmid
Competent cells are cells that
can take up DNA from their surrounding environment and integrate it into their own chromosomes by recombination.
Mice that are injected with only the R strain of Streptococcus pneumoniae
stay healthy, because their immune systems can kill this strain easily.
What characteristic of the S strain allows it to evade the immune system of the mice?
The cells have a capsule.
What most likely explains the recovery of live S strain cells from a mouse injected with heat-killed S strain mixed with live R strain cells?
The R strain picked up the S strain DNA, enabling it to produce a capsule
Which finding is most surprising from Griffith's experiments?
S strain cells are isolated from the blood of mice infected with heat-killed S strains and live R strains.
What is unique about transduction compared to normal bacteriophage infection?
Transduction transfers DNA from the chromosome of one cell to another.
How is generalized transduction different from specialized transduction?
Generalized transduction is initiated during lytic cycle of a virulent bacteriophage; specialized transduction is initiated during the lysogenic cycle of a temperate bacteriophage.
A transducing phage
contains fragments of the host chromosome instead of the viral genome.
When a transducing phage interacts with a new host cell,
the DNA from the previous host can recombine with the new host chromosome.
What is the outstanding characteristic of the Kingdom Fungi?
Members absorb dissolved organic matter.
Which of the following characterizes the Domain Bacteria?
prokaryotic cells; ester linkages in phospholipids
Which of the following statements about members of the Kingdom Plantae is false? They are multicellular They use organic carbon sources.
They undergo photosynthesis They are composed of eukaryotic cells They synthesize organic molecules.
They use organic carbon sources.
Which of the following statements about the members of the Kingdom Animalia is false?
They are multicellular They undergo photosynthesis.
They are composed of eukaryotic cells They ingest nutrients through a mouth They are heterotrophs.
They undergo photosynthesis.
A genus can best be defined as
a taxon composed of one or more species and below family.
A bacterial species differs from a species of eukaryotic organisms in that a bacterial species
is a population of cells with similar characteristics.
The phylogenetic classification of bacteria is based on
rRNA sequences.
What is a reason for NOT classifying viruses in one of three domains rather than in a fourth domain?
Viruses are not composed of cells.
Protists are a diverse group of organisms that are similar in
rRNA sequences.
In the scientific name Enterobacter aerogenes, Enterobacter is the
genus.
The arrangement of organisms into taxa
shows degrees of relatedness between organisms.
Bacteria and Archaea are similar in which of the following?
considered prokaryotic cells
Which of the following best defines a strain?
a pure culture that is not totally identical to other cultures of the same species
Into which group would you place a multicellular heterotroph with chitin cell walls?
Fungi
Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?
Proteobacteria (gram-negative bacteria)
How are negative stains different from other types of stains?
They stain the background, leaving the cells colorless.
Which of the following is an example of a dye used in a simple stain?
Methylene blue
How does the malachite green stain enter an endospore?
It is heated.
Following an endospore stain, how does one distinguish endospores from vegetative cells?
Vegetative cells are pink, endospores are green.
What is the fundamental purpose of staining in light microscopy?
To increase the contrast and visibility of the specimen
Possess axial filament and no axial filament
spirochetes
What is found primarily in the intestines of humans?
facultatively anaerobic gram-negative rods
Which of the following is NOT a characteristic inherent of the non-endospore-forming gram-positive rods?
nonpathogenic
Which of the following is NOT a characteristic of Neisseria?
requires X and V factors
Staphylococcus and Streptococcus can be easily differentiated in a laboratory by which one of the following?
growth in high salt concentrations
Which of the following genera is an anaerobic gram-negative rod?
Bacteroides
Which of the following do you expect to be MOST resistant to high temperatures?
Bacillus subtilis
Which of the following is NOT an enteric?
Campylobacter
Which of the following is NOT a characteristic of spirochetes?
easily observed with brightfield microscopy
Which of the following lacks a cell wall?
Mycoplasma
Which of the following bacteria is gram-negative?
Treponema
Which of the following form conidiospores?
actinomycetes and related organisms
Which of the following pairs is mismatched? dissimilatory sulfate-reducing bacteria - produce H2S// archaea - extremophiles// actinomycetes - reproduce by fragmentation// chemoautotrophic bacteria - fix atmospheric nitrogen// Cytophaga - a gliding, nonfruiting bacterium
chemoautotrophic bacteria - fix atmospheric nitrogen
Rickettsias differ from chlamydias in that rickettsias
require an arthropod for transmission.
Which of the following bacteria is gram-positive? Pseudomonas, Salmonella, Streptococcus, Bacteroide Rickettsia
Streptococcus
Escherichia coli belongs to the
proteobacteria.
Which of the following statements about the causative agent of Rocky Mountain spotted fever is FALSE? It is an intracellular parasite. It is transmitted by ticks It is in the genus Rickettsia.
It is found in soil and water. It is gram-negative.
It is found in soil and water.
What bacteria are responsible for more infections and more different kinds of infections?
Streptococcus
What is best reason to classify Streptococcus in the Lactobacillales?
rRNA sequences
Streptomyces differs from Actinomyces because Streptomyces
is a strict aerobe.
All of the following bacteria are gram-positive. Which does NOT belong with the others? Actinomyces Bacillus Corynebacterium
Listeria Mycobacterium
Listeria
Salmonella, Shigella, Yersinia, and Serratia are all
gram-negative facultatively anaerobic rods.
You have isolated a gram-positive rod. What should you do next?
endospore stain
Borrelia is classified as a spirochete because it
possesses an axial filament.
You have isolated a prokaryotic cell. The first step in identification is a(n)
Gram stain.
You have isolated an aerobic gram-positive, endospore-forming bacterium that grows well on nutrient agar. To which of the following groups does it most likely belong?
bacillales
Which of the following pairs is mismatched?
Pseudomonas - gram-positive
All of the following bacteria are motile. Which does NOT have flagella? Escherichia, spirochetes
Pseudomonas, helical bacteria, Salmonella
spirochetes
Mycoplasmas differ from other bacteria in that they
lack a cell wall.
T or F Two distinguishing factors of the epsilonproteobacteria that they are motile and microaerophilic.
True
T or F The Gram stain is not suitable for identifying members of the Archaea.
False
All gram-negative bacteria are classified as proteobacteria.
False
The deinococci can be categorized as extremophiles.
True
Currently, no members of Archaea have been linked to human disease.
True
The human body is typically free of archaeal species.
False
Which of the following statements about helminths is FALSE? All are parasites. They are multicellular animals. They have eukaryotic cells. They are heterotrophic. Some have male and female reproductive organs in one animal.
All are parasites.
Which of the following statements regarding fungi is FALSE? Fungi reproduce by forming asexual or sexual spores. Fungi are eukaryotic heterotrophs.
Most fungi are pathogenic for humans. Most fungi grow well in acidic culture condition. Fungi tolerate low moisture conditions.
Most fungi are pathogenic for humans.
which of these spores are characteristic of Penicillium?
Ascospore conidiospore
Which of the following pairs is mismatched? anamorphs lack spores Ascomycota conidiospores
Zygomycota sporangiospores microsporidia lack mitochondria Basidiomycota basidiospores
anamorphs lack spores
What spores are characteristic of Rhizopus
Sporangiospore, Zygospore
What spores are asexual spores?
Arthroconidium, Blastoconidum, Chlamydoconodium, Condiospore, Sporangiospore
Which of the following statements regarding protozoa is FALSE? Nearly all protozoa cause disease. Protozoa are unicellular eukaryotes.
Most protozoa reproduce asexually. Protozoa are common in water and soil. Some protozoan pathogens are transmitted by arthropod vectors.
Nearly all protozoa cause disease.
Which of the following pairs is mismatched?
teleomorph produces both sexual and asexual spores, coenocytic hyphae hyphae with cross-walls
dimorphic fungus grows as a yeast or a mold, systemic mycosis fungal infection of body organs,
dermatomycosis fungal infection of the skin
coenocytic hyphae hyphae with cross-walls
Which of the following tends to be more complex in a parasitic helminth than in free-living helminths?
reproductive system
Which of the following statements is FALSE? Fungi produce sexual spores. Fungal spores are highly resistant to heat and chemical agents. Fungal spores are used in identification of fungi. Fungi produce asexual spores. Fungal spores are for asexual or sexual reproduction.
Fungal spores are highly resistant to heat and chemical agents.
Which of the following pairs is mismatched? dinoflagellates - paralytic shellfish poisoning
brown algae - algin red algae - agar diatoms - petroleum green algae - prokaryotic
green algae - prokaryotic
Helminthic diseases are usually transmitted to humans by
gastrointestinal route.
All of the following are characteristic of the Platyhelminthes EXCEPT that they
have highly developed digestive and nervous systems.
In the malaria parasite life cycle
humans are the intermediate host and mosquitoes are both the definitive host and the vector.
Three weeks after a river rafting trip, three family members experienced symptoms of coughing, fever, and chest pain. During the rafting trip, the family had consumed crayfish that they caught along the river banks. An examination of the patients sputum revealed helminth eggs, and serum samples were positive for antibodies to Paragonimus. All of the family members recovered following treatment with praziquantel. In the Paragonimus life cycle,
humans are the definitive host and crayfish are the intermediate host.
The encysted larva of the beef tapeworm is called a
cysticercus.
A definitive host harbors which stage of a parasite?
adult
What do tapeworms eat?
intestinal contents
Giardia and Trichomonas are unusual eukaryotes because they
lack mitochondria.
Which of the following is the most effective control for malaria?
eliminate Anopheles
Assume you have isolated a multicellular heterotrophic organism that produces coenocytic hyphae, motile zoospores, and cellulose cell walls. It is most likely a(n)
oomycote alga.
If a larva of Echinococcus granulosus is found in humans, humans are the
intermediate host.
Ringworm is caused by a(n)
Fungus
Yeast infections are caused by
Candida albicans.
You see acid-fast oocysts in a fecal sample from a patient who has diarrhea. What is the MOST likely cause?
Cryptosporidium
True or False Arthropod vectors are blood-sucking animals such as ticks, lice, and fleas that transmit microbial pathogens.
True
T or F Cercariae, metacercaria, redia, and sporocysts are all life cycle stages of trematodes.
True
T or F The Platyhelminthes group includes roundworms, tapeworms, and flukes.
False
T or F Some species of dinoflagellates produce neurotoxins that cause fish kills and red tides.
true
T or F The sporozoite, merozoite, gametocyte, and ring stages are all part of the Plasmodium life cycle.
True
Most cases of hookworm infection are acquired by ingestion of eggs in contaminated food or water.
False
How do all viruses differ from bacteria?
Viruses are not composed of cells.
What is the most significant support for the idea that viruses are nonliving chemicals?
They cannot reproduce themselves outside a host.
Which of the following statements about viral spikes is FALSE? They are found only on nonenveloped viruses. They are used for attachment. They may cause hemagglutination.
They bind to receptors on the host cell surface.
They are composed of carbohydrate-protein complexes
They are found only on nonenveloped viruses. they are founf on enveloped viruses
Which of the following is NOT utilized to culture viruses? laboratory animals/ bacterial cultures/ embryonated eggs/ animal cell cultures/ culture media
culture media
Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps? attachment/ biosynthesis/ uncoating/ penetration/
release
biosynthesis
phage DNA is incorporated into host cell DNA.
definition of lysogeny
Infectious piece of RNA without a capsid.
A viroid
A clear area against a confluent "lawn" of bacteria is called a
plaque.
A persistent infection is one in which
the disease process occurs gradually over a long period.
Which of the following statements is FALSE?
A prophage is phage DNA inserted into a bacterial chromosome. The prophage makes the host cell immune to infection by other phages. Prophage genes are repressed by a repressor protein coded for by the prophage. A prophage may result in new properties of the host cell. A prophage can "pop" out of the chromosome.
The prophage makes the host cell immune to infection by other phages.
Lysogeny can result in all of the following EXCEPT
immunity to reinfection by the same phage.
immunity to reinfection by any phage.
acquisition of new characteristics by the host cell.
specialized transduction. phage conversion.
immunity to reinfection by any phage.
An infectious protein is a
Piron
An envelope is acquired during which of the following steps?
Release
Which of the following statements is NOT true of lysogeny? It causes lysis of host cells.
Prophage is inserted into the host genome. Lytic cycle may follow lysogeny. It is a "silent" infection; the virus does not replicate. It can give infected pathogens the genetic information for toxin production.
It causes lysis of host cells.
An example of a latent viral infection is
cold sores
A virus ability to infect an animal cell depends primarily upon the
presence of receptor sites on the cell membrane.
The mechanism whereby an enveloped virus leaves a host cell is called
budding.
The most conclusive evidence that viruses cause cancers is provided by
cancer following injection of cell-free filtrates.
Into which group would you place a photosynthetic cell that lacks a nucleus?
Bacteria
What is characteristic of Clostridium
endospore-forming cocc
Bacteriophages derive all of the following from the host cell EXCEPT
lysozyme.
Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves
injection of naked nucleic acid into the host cell.
Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT RNA polymerase.
nucleotides// DNA polymerase// tRNA// None of the answers are correct
DNA polymerase.
Which of the following places these items in the correct order for DNA-virus replication?
1. Maturation
2. DNA synthesis
3. Transcription
4. Translation
2-3-4-1
A viral species is a group of viruses that
has the same genetic information and ecological niche.
Viruses that utilize reverse transcriptase belong to the virus families
Hepadnaviridae and Retroviridae.
A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?
The virus is causing the death of the infected cells in the patient.
Which of the following statements about viruses is FALSE? Viruses contain DNA or RNA but never both.// Viruses contain a protein coat// Viruses use the anabolic machinery of the cell// Viruses have genes// Viruses use their own catabolic enzymes.
Viruses use their own catabolic enzymes.
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called
latent viruses.
Assume a patient had chickenpox (human herpesvirus 3) as a child. Which line on the graph in the figure would show the number of viruses present in this person as a 60-year-old with shingles (human herpesvirus 3)?
E
The following steps occur during multiplication of herpesviruses. Which is the third step?
uncoating
Cause tumors to develop.
Oncogenic viruses
Which one of the following steps does NOT occur during multiplication of a picornavirus? synthesis of + strands of RNA// synthesis of DNA//synthesis of viral proteins// synthesis of - strands of RNA
None of the answers is correct.
synthesis of DNA
Most RNA viruses carry which of the following enzymes? DNA-dependent DNA polymerase//
lysozyme// reverse transcriptase// RNA-dependent RNA polymerase//ATP synthase
RNA-dependent RNA polymerase
T or F The basic mechanism of viral multiplication is similar for all viruses.
True
T or F Binomial nomenclature is used to name viruses.
False
T or F Glycoprotein spikes are found on the capsids of all viruses.
False
T or F Dogs do not get measles because their cells lack the correct receptor sites for that virus.
True
Helical and icosahedral are terms used to describe the shapes of a virus envelope. T or F
False - Capsid
Viruses are the only known infectious agents that are obligatory intracellular parasites. T or F
False
Most drugs that interfere with viral multiplication also interfere with host cell function. True or False
True
Why are archaea and bacteria—both collections of prokaryotic organisms—grouped into different domains while organisms like fungi and animals are in the same domain?
Bacteria and archaea differ significantly in their rRNA sequences, but fungi and animals share some rRNA characteristics.
While working with a broth culture of archaea in the laboratory, you accidentally spill some of the microorganisms on yourself. Do you need to be concerned about developing an infection? Why or why not?
No; archaea are not pathogenic.
Which of the following methods could be used to differentiate between a member of domain Bacteria and a member of domain Archaea?
You could look for the presence of peptidoglycan.