Micro Exam 1
Viability of a bacterial endospore is mostly dependent on ________ of the endospores.
.the acidic proteins that tightly bind the DNA genome
The Second Golden Age of microbiology spanned _________, and a major discovery of the period is
1940-1970/ electron microscopes
A bristle of an insect is 0.25 mm in length. A maximum of how many bacteria of diameter 0.80 æm can be placed on the bristle (in a linear single file)?
312.
The diameter of a spherical cell is 2.0 mm. What is the volume of the cell, and which domain could the cell possibly belong to? Note: The volume of a sphere is V=4/3pr3, where r is the radius of the sphere.
4.18 mm3/Archaea
The anticodon of a tRNA is 5'UCC3'. The codon the tRNA would recognize is ______, and the amino acid the tRNA would carry is
5'GGA3'/ Gly
Which of the following completes the initiation step of chromosomal DNA replication?
A DNA polymerase III holoenzyme binds the sliding clamp and replaces the primase.
Which of the following protozoans may infect a person drinking chlorinated drinking water?
A protozoan that may form cysts.
Which of the following statements is self-evident?
All acellular microbes depend on cellular microbes.
Which of the following microbes is also a microorganism?
An archaeon.
A virus with ________ capsid may not have a fixed shape and size.
An enveloped helical capsid.
Which of the following is a fungus?
Any of these organisms. (It decomposes dead plants and animals or infects live plants and animals. It produces toxins that can affect human health. It is a single-celled organism, or it has a thread-like structure. It synthesizes antibiotics used in treating some microbial infection)
Which of the following defines bioinformatics?
Application of computer technologies in studying biological information.
Which of the following statements on microbes is correct?
Archaea pathogenic to humans have never been reported.
Which of the following RNAs is used by the cell without any grooming?
Bacterial mRNAs
Which of the following is structurally and functionally similar to the kinetosome of a eukaryotic cell?
Centriole.
Which of the following structures is a lipid membrane-bound organelle?
Chlorosomes of the green photosynthetic bacteria.
Some bacteria fixed on a glass slide were stained with crystal violet, soaked with iodine, and then washed with alcohol. Which of the following bacteria can be visible on the slide if examined using an LM?
Clostridium botulinum, a G(+) bacillus.
Which of the following are fungal asexual spores?
Conidia and arthrospores
Which of the following describes satellite viruses?
DNA or RNA genome, have genes including genes for capsid proteins, yet needs a helper virus for infection.
Controls are needed to minimize the effects of all variables other than the independent variable on an experiment. If hand washing is the ?independent variable? and the fraction of the patients who developed a puerperal fever after childbirth is the ?dependent variable? in Semmelweis? controlled experiment, which of the following is the control?
Doctors did not wash their hands before assisting childbirths.
Which of the following is not a means of multiplication (i.e. reproduction) of bacterial species?
Endospores of Clostridium tetani.
Which of the following bacteria has a thin cell wall hidden in the periplasmic space created by two membranes?
Escherichia coli, a G(-) bacillus.
When stained using safranin or methylene blue, spirochetes are generally not visible by an LM. However, if stained with a fluorescent dye, the bacteria are easily visible. Why?
Fluorescently stained objects glow when excited by light of a particular wavelength.
Which of the following samples (all wet-mounted on a glass slide) is unsuitable for examination using a simple LM?
Fungi- stained with calcofluor white.
The intermediate filaments are polymers of
Heat: phototaxis.
Which of the following statements about a functional tRNA is correct?
It contains the acceptor stem, D loop, TpC loop, and anticodon loop.
Which of the following worms is a fluke (i.e. a trematode), and not a tapeworm?
It has a flat non-segmented body
Which of the following is most likely a eukaryotic cell?
It has mitochondria and chloroplasts.
Which of the following virus particles is a virion?
It is capable of infecting its host cell.
Which of the following statements about the cell wall of the eukaryotic cell is correct?
It may contain several types of polysaccharides, or silicates, or carbonates.
Which of the following statements is associated with all microbes?
Microbes are genome creatures.
Which of the following disciplines studies microbes in the environment and the interactions among microbes?
Microbial ecology.
Which of the following areas of microbiology can be considered part of systems biology?
Microbial pathology. Microbial physiology. Environmental microbiology. Microbial ecology. (each of these)
Which of these algal species would be more likely to infect other organisms?
One that lacks chloroplasts and cannot synthesize food molecules
In taxonomy, related ________ are grouped to a Class.
Orders
That DNA is the carrier of heredity of cellular organisms was discovered by
Oswald Avery and his colleagues (1944)
Which of the following characteristics of bacterial glycocalyces would contribute the least to the pathogenicity of pathogenic bacteria already present in the body cavity of a patient? Group of answer choices
Preventing from rapid desiccation.
You want to count the fraction of live spermatozoa of male mice. The mice were previously treated with polychlorinated biphenyl (PCB). Which of the following methods would you use?
Put a drop of the diluted semen on a glass slide and examine using a dark-field LM.
A genome can be made of
RNA or DNA
Which of the following enzymes transcribe eukaryotic tRNA genes?
RNAP II or III
The genomes of RNA viruses are replicated by the enzyme _____________, and the genes of cellular organisms are transcribed by _
RdRPs/ DdRPs
Which of the following statements about cellular genomes is incorrect?
Ribosomal RNAs are synthesized in the Cajal bodies of the nucleus.
If a eukaryotic cell receives a mitogenic signal, the cell enters ______ and replicates DNA.
S phase
Which of the following statements is correct about common dyes/pigments used in staining bacteria?
Safranin is a positively charged dye, and it binds certain cellular components.
Which of the following steps of processing a tissue is actually for drying the sample?
Soaking the tissue with absolute alcohol.
Which of the following statements is incorrect about a TEM?
TEMs require the specimens to be coated with metal nanoparticles.
Which of the following is a substrate of DNA polymerase III of E. coli?
The 3' OH end of the RNA or a DNA primer.
Which of the following is the most accurate description of a genome?
The DNA or RNA contents carrying the genetic blueprint of a species.
Which of the following describes the end of transcription initiation and is not a feature of transcription elongation (in E. coli)?
The RNAP synthesizes an RNA molecule <10 nts in size.
Which of the following pairs of terms is not intrinsically related?
The basal body.
Which of the following is most likely a helical capsid?
The capsid is a nucleocapsid.
All these viruses are visible on a TEM image of a thin slice of a mammalian cell. Which of the viruses is most certainly an enveloped virus?
The cell is intact, and the viruses are budding out of the plasma membrane of the cell.
Which of the following statements is true about roundworm
The function of the kidney of the worms is performed by renette cells.
Which of the following is most likely a bacterial gene?
The gene is transcribed to make a polycistronic mRNA.
Which of the following theories contributed to the development of microbiology the most?
The germ theory of disease.
Which of the following virus names (mentioned in the sentences) is/are written correctly?
The herpes simplex virus type 1 has a DNA genome. HSV-1 has an enveloped capsid. Human alphaherpesvirus 1 causes fever blisters.
All of the following except _____can be used again to synthesize proteins soon after transcription termination and disassembly of the 70S ribosome?
The newly synthesized polypeptide chain
Which of the following is generally the first step of initiation of protein synthesis in a bacterial cell? The anticodon of the tRNA aligns with the mRNA codon The small subunit ribosome binds an mRNA The large subunit ribosome joins the small subunit ribosome The small subunit ribosome binds a charged tRNA
The small subunit ribosome binds an mRNA
Mutation is defined as any changes in the nucleotide sequence of a genome. Which of the following genome creatures may readily mutate the genome of their host cells?
Transposons and mobile introns.
In terms of optics, what was the critical difference between D'Armati?s eyeglasses and Leeuwenhoek?s microscopes?
Use of a focusing mechanism.
What is/are the difference(s) between a vegetative cell and a spore?
Vegetative cells are highly protected (thick-coated), spores are not. Vegetative cells are metabolically active (they eat), spores are not. Correct Answer Two of these options are correct. Vegetative cells are reproductively active (they divide), spores are not.
Which of the following agents readily move from one host cell to another host cell?
Viruses and plasmids.
Which of the following groups of eukaryotes have metazoan microbes?
Worms and arthropods.
Phylogenetic classification implies that
all the lower taxa within a higher taxon originated from a common ancestor
A flatworm has many proglottids, so it cannot have
an alimentary tract
Mobile DNA element? is a more appropriate name for transposons because transposons ________.
are found in different locations of the genomes of different members of the same species
Microbiologists consider all microbes as aquatic beings except some _______, because most microbes ________.
arthropods/ quickly desiccate if exposed to open air and sunlight
The umbrella-shaped structures of mushrooms are ________, where the asci or the basidia are housed.
bacteria lacking a cell wall
Which of the components of a bacterial flagellum provide it with motility by acting as a proton motor?
basal body
Bacteria and archaea may thrive in
boiling geysers and thermal vents of seafloor the driest deserts and the permafrost of the tundra the deepest ocean trenches and the highest mountain peaks body surfaces and inside the cells of living organisms.
Okazaki fragments
can be partly DNA, partly RNA
The resolving power of a TEM is 2. It means that the scope
can produce distinct images of two objects placed just 2 nm apart
The nucleotide sequence of an mRNA is 3'G5'GCCAGGAUGCCCGGGAAAUUUCCCCAGUGAUUUAAACCCAAAAAAAAAAA3'. The mRNA is most likely from________ and it has an ORF with_____ codons for amino acids.
eukaryotes /7.
Chromatin
fibers are 11 or 30 nm in thickness
The nuclear envelope is different from any other cellular membranes for having
four lipid layers
Which of the following describes an apical complex?
fruiting bodies or sporocarp
Available evidence indicates that people of antiquity _________ microbes
grew and utilized
An isolate of a microbe is currently identified as X1003878E2014. The isolate is most likely
has not been grown in the laboratory or fully characterized yet
Pasteur was unable to prove the germ theory of disease because
he used liquid culture media to grow microbes
Pasteurization (i.e. heating grape juice at 60oC for 30 minutes before fermentation) solved the problem of wine-souring because boiling
killed bacteria but preserved heat-resistant yeasts
The organs of the roundworms are housed in the false body cavity (i.e. the pseudocoelom) of the animals. It is called a false body cavity because it
lacks a complete peritoneal membrane
The reaction of peptide bond formation between the amino acid of the A site tRNA and the amino acid or peptide chain of the P site tRNA is catalyzed by the enzyme activity (peptidyl transferase activity) of the
large subunit ribosome
Which of the following RNA molecules has a direct role in protein synthesis?
mRNAs 26S rRNAs tRNAs 18S rRNAs
Early philosophers and naturalists developed knowledge by all of the following methods except
making and testing hypotheses
The scientific method (originally enunciated by Ibn al-Haytham in 1000 AD and popularized in the West by Roger Bacon in 1250 AD) involves each of the following except_________.
making logical deductions/claims without conducting an experiment
The nucleotide sequence of an mRNA is 5'GCCAGGAUGCCCGGGAAAUUUCCCCAGUGAUUUAAACCCAAAAAAAAAAA3'. What is the amino acid sequence of the ORF present in this mRNA? Please use a genetic code table to answer the question.
met-pro-gly-lys-phe-pro-gln
Lions (Panthera leo) and tigers (Panthera tigris) often breed in zoos and some of their offspring (i.e. ligers and tigons) are fertile (i.e. ligers and tigons may sire cubs and the cubs grow to adulthood and may sire cubs). Do tigers and lions belong to the same species?
no
Mitochondria and chloroplasts are somewhat comparable to
protein synthesis
The nucleoid of prokaryotes and the nucleus of eukaryotes are the sites for all of the following processes except
protein synthesis
An agent lacks a genome, yet it causes diseases among animals. The agent is made of ______ and it is a ______.
proteins/prion
All genome creatures may
replicate, mutate and evolve
A virusoid is a _______ that has a circular RNA genome and a stolen capsid.
satellite
A G(+) bacterium normally lives in seawater (3.5% salt concentration). If the bacterium is placed in a tube of freshwater (salt concentration less than 0.5%), the bacterium will
survive unaffected at least for several hours
The genes present in RNA genomes may contain
terminators open reading frames promoters
When the genome of the bacterial virus lambda replicates inside E. coli, it produces concatemers. this means
the genome replicates by the rolling circle method and creates many copies of the genome
Discoveries and inventions in the field of microbiology have put modern civilization in a unique situation, and that situation has contributed to many of the concerns of our time. The unique situation is
the rapid growth of the human population
Typical bacteria and the endosymbionts such as mitochondria and chloroplasts share all of the following characteristics or have comparable structures, except
thylakoid or cristae
The normally growing, metabolically active (i.e. feeding) or vegetative protozoan cell is a _
trophozoite
A tRNA is in the P site of a 70S ribosome. The tRNA is not an initiator tRNA. How many amino acids is the tRNA carrying?
two or more
All of the following genome creatures can be considered potential parasites of viruses except
viroids and plasmids