Microbiology Exam Ch1-17 to be continued

Need to do ch 8 9 and 17

What organisms are not considered microbe?

Mosquitoes

Rank the following organism Largest to smallest: Pelomyxa, Escheria Coli, Varicella Zoster Virus, Prochlorococcus, Spirogyra

Pelomyxa, Spirogyra, Escheria Coli, Prochlorococcus, and Varicella Zoster Virus

Where is Pelomyxa found

Ameba found in the soil

Spirrogyra is found where

Aquatic algae

Escheria Coli is found where

Bacteria found in the human colon

Prochlorococcus is found where

Potosynthetic marine bacteria

Varicella zoster virus is what?

Virus that causes chicken pox

Florence Nightingale's statistical analysis of the leading causes of mortality of British soldiers convinced the British government to do all the following except

supply soldiers with additional weapons and ammunition.

Although Vibrio cholerae is approximately 0.5 µm wide and 1.5 µm in length, filtering water contaminated with Vibrio cholerae  through a cloth with 20-µm mesh holes was successful in reducing cholera infections in Bangladesh. What might be a possible explanation?

 Vibrio cholerae may be growing in complex multicellular assemblages such as a biofilm

What type of organisms belong in bacteria

Proteobacteria and Cyanobacteria

What type of organisms belong in eukaryotes

Protists, Plants, Fungi, Algae, Animals

What type of organism belongs in Archea?

Sulfur thermophiles, Methanogens

What did Hooke contribute to microbiology

the first to record observations of microbes through simple microscopes

What did Spallanzani contribute to microbiology

showed that microbes arise from preexisting microbes and that heat sterilization can prevent microbial growth

What did Pasteur contribute to microbiology

discovered the microbial basis of fermentation and showed that providing oxygen does not enable spontaneous generation

What did Tyndall contribute to microbiology

Showed that repeated cycles of heat were necessary to eliminate spores formed by certain kinds of bacteria

What did Nightingale contribute to microbiology

statistically quantified the impact of infectious disease on human populations

Spontaneous generation is the notion that

living organisms arise from nonliving matter

What characteristic of endospores led to confusion when Tyndall tried to replicate Pasteur's experiments regarding spontaneous generation?

Heat resistance

Which of the following is true of a pure culture

It is a culture of a single type of organism that can facilitate identification of a pathogen.

What are the steps of Kochs postulates

The microbe is found in all cases of the disease. The microbe is isolated from the disease host and grown in pure culture. When the microbe is introduced into a healthy, susceptible host, the same disease occurs. The same strain of microbe is isolated from the newly diseased host.

What criteria of Koch's postulates would not necessarily be met when trying to link a particular bacterium to a latent infection, such as tuberculosis or Lyme disease?

he microbe is found in all cases of the disease but is absent from healthy individuals. When the microbe is introduced into a healthy, susceptible host, the same disease occurs.

What did Fleming contribute to Microbiology

discovered that the Penicillium mold generates a substance that kills bacteria

What did Ivanovsky contribute to Microbiology

discovered viruses as filterable infective particles

What did Koch contribute to Microbiology

Devised techniques of pure culture to study a single species of microbe in isolation

What did Jenner contribute to Microbiology

established the practice of vaccination (inoculation with cowpox to prevent smallpox)

What did Semmelweis contribute to Microbiology

Showed that antiseptics could prevent the transmission of pathogens from doctor to patient.

What is a unique characteristic of viruses that distinguishes them from all major groups of microorganisms in the Bacteria, Archaea, and Eukarya domains?

lack of typical cell structure

What organisms can be infected by viruses.

Archaea, Fungi, Plants, Bacteria, Protists, Animals

Most organisms (including you) break down organic compounds to obtain energy and nutritional building blocks. In contrast, chemolithotrophs are prokaryotes that obtain energy through the oxidation of inorganic compounds. What inorganic molecules would these microbes also need to build macromolecules for new cell material?

CO₂

The ocean is the largest biome on planet Earth, and its biomass is dominated by microbes. Aside from their importance to marine ecosystems, photosynthetic marine microbes also play a major role in composing the Earth's atmosphere. How do photosynthetic marine microbes affect Earth’s atmosphere?

They produce 50% of Earth’s oxygen gas

Early microbial ecologists knew that hydrogen gas is oxidized in soil and that ammonia is oxidized in sewage. How did these scientists determine that microbes are responsible for these ecological reactions?

by applying heat and antimicrobial treatment to sewage samples and observing that nitrate was no longer formed

Vascular plants absorb the majority of their essential nitrogen from soil in the form of?

ammonium, and nitrate

Microbial endosymbiosis, in a variety of diverse forms, is widespread in all ecosystems. Many interesting cases involve animal or human hosts. Endosymbiotic microbes make essential nutritional contributions to host animals. Ruminant animals such as cattle, as well as insects such as termites, require digestive bacteria to break down cellulose and other plant polymers. Even humans obtain about 15% of their nutrition from colonic bacteria. Intestinal bacteria such as E. coli and Bacteroides species grow as biofilms, organized multispecies communities adhering to a surface. Biofilms play major roles in all ecosystems and within parts of the human body. Microbial enzymes are required for digesting most kinds of plant fibers that we consume. What is the primary function of ruminant microorganisms?

 digestion of cellulose to organic acids

What would not be considered an endosymbiont?

 intracellular bacteria, such as Mycobacterium tuberculosis, that inhibit macrophage apoptosis

Which of the following domains are phylogenetically more closely related to each other?

 Archaea and Eukarya

Identify the three domains of life according to the classification system developed by Carl Woese.

Bacteria, Archea, and Prokarya

Scientists are continuously advancing our understanding of the importance of the human gut microbiome in health and disease. Which of the following is not a challenge associated with studying the human microbiome?

 Genomic sequencing of the gut microbiome cannot be completed

Astrobiologists study the origin of life in the universe and the possibility of life beyond Earth. Which of the following is not a reason why astrobiology involves microbiology?

 Scientists are trying to colonize Mars with microorganisms from Earth in an effort to determine whether life can survive on other planets.

The invention of the ultracentrifuge led to rapid advances in cell biology by allowing scientists to do what?

fractionate subcellular parts

Of the following animals, __________ have the sharpest vision due to closely packed __________.

 hawks; photoreceptors

A blank is one-millionth of a millimeter.

nanometer

Resolution refers to what?

Smallest distance by which two objects can be separated and still be distinguished as separate

What would be the best electromagnetic energy to use to get the greatest resolution of a bacterial cell? 

ultraviolet

What are two important reasons why microscope lenses are glass parabolas?

glass for refractive index and parabola for bending light rays to intersect at a focal point

Why are human eyes not able to use all of the information in visible light?

The distance between photoreceptors is greater than the wavelength of visible light

What lens does not magnify an image?

condenser

Assume you are using a microscope that has the ability to provide specific wavelengths of light. Which of the following provides the best minimum resolution distance?

a system using a wavelength of 400 nm with an angle of the light cone being 72° in air

In some cases, a set of objective lenses on a microscope can be interchanged without losing good focus of a specimen. The term used to describe this is

Parfocal

In what ways are wet mount slide preparations disadvantageous when viewing live specimens?

bacteria appear "hollow", boils specimen

What would not be an advantage to heat-fixing a bacterial specimen to a slide?

allows visualization of flagellar function

Clostridium difficile is a common and serious infectious agent that causes severe intestinal distress. When cells of C. difficile are Gram-stained, they appear as Gram- Blank rods, which are blank in color and belong to the phylum of bacteria known as blank

Positive, Purple, Firmicutes

Although the Gram stain provided a tentative identification of C. difficile, which of the following stains would most likely provide the specificity needed to identify the bacteria as C. difficile?

 antibody tags

What would be a Gram stain negative?

Bacteroidetes, Escherichia coli, Proteobacteria

What would be positively identified by an acid-fast stain?

Mycobacterium paratuberculosis

What are the the steps and spectra of fluorescence

Excitation spectrum of a fluorophore, having the Photon provides energy to electron, leading Electron to have absorbed photon's energy, causing Electrons to move down orbitals, releasing light making the Electron returns to stable orbital. Making there be Emission spectrum of a fluorophore.

What makes Fluorophore DNA/components seperated?

Origin sequence tagged with fluorophore, Labeled antibody to helicase, and DAPI (4',6-diamidino-2-phenylindole)

What makes fluorophore associated with other components

Fusion reporter of GFP and ATP synthase, FM4-64 lipophilic dye, Labeled antibody to B -galactosidase, Labeled antibody to aquaporin

What technologies describes how super-resolution imaging can track a single molecule inside of a cell, even though the resolution limit of light is much larger than the molecule being tracked?

 computation of central peak position based on intensity profile

What best describes the unusual image alterations that occur when using differential interference contrast microscopy

 false 3D effect

What explains why electron microscopes provide a much more detailed image of specimens than light microscopes?

 Electrons have much shorter wavelengths than visible light waves

identify what techniques have similarities to scanning electron microscopy (SEM) for the reason given.

SEM and transmission electron microscopy use the same illumination source.
SEM and differential staining both only use one stain. SEM and differential interference contrast microscopy both provide a 3D image of the cell surface.

What is the main advantage of scanning probe microscopy as compared to transmission EM or normal scanning EM?

Scanning probe microscopy can be used to view live microbes

How does flash-freezing the samples examined by cryo-EM improve the resolution of the resulting images?

Flash-freezing retains water in the sample but eliminates ice crystals.

Modern high-intensity electron beams have helped cryo-EM techniques to image the internal ultrastructure of one of the smallest and most abundant microbes in the ocean, Pelagibacter. This organism plays an important role in the carbon cycle by recycling dissolved organic matter. What can high-intensity electron beams do that makes them more effective than earlier microscopy instruments?

 detect smaller structures

What are some things regarding phase-contrast microscopy?

When parts of the cell have different refractive indices, they can be distinguished in the image.
Destructive and constructive interference of light waves lead to light and dark areas when the specimen is viewed. A phase-contrast microscope creates high contrast, allowing observation of delicate features.

Transmission electron microscopy was used by Mauricio Toro-Nahuelpan to visualize the magnetosomes, as they are located inside the cell. However, which type of microscopy would work best if the magnetosomes were located on the outside of the cell?

 scanning electron microscopy (SEM)

Antibiotics that weaken the peptidoglycan cell wall make a bacterium more prone to

osmotic lysis

All cells are made up of water and essential ions as well as small and large organic molecules. Order the following components in E. coli during balanced exponential growth from greatest to least in terms of percentage of total cellular weight.

Water, Protein, Nucleic acids such as DNA and RNA, Lipids, Inorganic Ions

What would not be a good represent research applications for cell fractionation

 determining whether a bacterium can metabolize certain sugars

Many bacteria adapt to adverse environmental conditions by modifying the composition of their cell membranes. For example, the membranes of bacteria subjected to heat stress often contain high levels of which of these compounds?

 saturated fatty acids

Active transport is required for bacterial cells to

transport solutes against their concentration gradient

Tetracycline is an antibiotic that works by binding to the 30S subunit of bacterial ribosomes, thus inhibiting protein synthesis. This drug is able to cross the cell membrane because

as a weak base, it can cross the membrane in its uncharged form

For an acid-loving microbe (acidophile) living in an acidic environment in the presence of both penicillin and tetracycline, which of the following will end up crossing into the cell and impacting the internal cytoplasmic pH? 

Form B of penicillin

Cells of a normally rod-shaped bacterium (e.g., Bacillus subtilis) that have completely lost the ability to produce the MreB protein would mostly likely be

coccoid-shaped

Bacteria exposed to quinolone-type antibiotics rapidly become unable to

carry out normal gene expression. condense and package their chromosomes and replicate their DNA.

Order the following events as they occur from beginning to end during DNA replication in a dividing cell

DNA at origin unzips and two replication forks form, Replisomes synthesize daughter chromosomes bidirectionally, Terminator site is replicated, Septum forms, Daughter cells seperate

Regarding the DNA polymerase enzymes, blank of these would be required if a new round of DNA replication began before the first one terminated.

Twelve

What is true of the newly synthesized daughter chromosomes?

 Each chromosome contains one parental and one newly synthesized DNA strand.

The cell envelope of a Gram-negative cell, such as Escherichia coli or Vibrio cholerae, contains

an inner, cytoplasmic membrane, a thin peptidoglycan cell wall, an outer membrane, porins

Reports of disease caused by enteropathogenic E. coli and its relative, Salmonella, usually include a description of the responsible serotype. For example, in 1993, hundreds of infections from Shiga toxin–producing E. coli resulted from undercooked hamburgers sold by Jack-in-the-Box restaurants. The outbreak was caused by the now infamous E. coli strain O157:H7. The "O" in this designation refers to an antigen on which of the following molecules?

lipopolysaccharide

In addition to providing structural support and mediating transport, membrane proteins are important for allowing bacteria to sense and respond to changes in their environment. For example, the ToxR protein is found in the plasma membrane of Vibrio cholerae cells. How does ToxR respond to pH and temperatures characteristic of the human gut environment?

 binding to the promoters of genes involved in virulence

The specific mode of action of ToxR is only possible because, as a prokaryote, Vibrio cholerae lacks what?

a nuclear membrane

What best describes a genome?

all the genetic information possessed by a cell or virus

What may be present as part of the prokaryotic genome? 

prophage, chromosome, plasmid

mechanism of gene transfer among microbes was elucidated by the team of Avery, MacLeod, and McCarty?

Transformation

Before the scientific advances of the mid-20th century, most scientists believed that a cell's genetic information was encoded by

Protein

What may be included in the genome of a bacterium or archaeon.

linear extrachromosomal plasmid(s), linear chromosome(s), circular chromosome(s), circular extrachromosomal plasmid(s) 

What DNA molecules would most likely have the highest denaturing temperature (melting temperature, T_m)?

   ACGGTGACGGCGCGAGC, TGCCACTGCCGCGCTCG

Analysis of the genome of a newly discovered bacterial strain reveals that it is composed of a double-stranded DNA molecule containing 16% thymine. Based on this information, what would you predict the percentage of cytosine to be

34%

Bacterial replication begins at a single, defined DNA sequence known as

oriC

The start of bacterial replication depends on the increase in the concentration of active blank which accumulates during the growth phase of the microbe.

DnaA

It is essential that sister chromosomes avoid the septum formation at the midline of the cell during bacterial cell division in order to prevent septal “guillotining” of chromosomes. Which of the following is not directly involved in the mechanism to prevent septal guillotining of chromosomes?

ParC

While plasmid replication is not tied to chromosomal replication, many of the proteins used for plasmid replication are host enzymes. Each plasmid contains its own origin of replication (ori) and only the few genes needed for replication. Which of the following proteins is needed for the rolling-circle mechanism of plasmid replication and is encoded by a plasmid gene?

RepA

What statements is true about the rolling-circle mechanisms of plasmid replication?

 RepA nicks one strand of the double-stranded DNA plasmid

Prokaryotic Only

topoisomerase IV

Eukaryotic Only

Telomerase

Both Cell Types Prokaryotic and Eukaryotic have

Helicase, DNA polymerase, DNA primase, ligase

What is not a mechanism by which plasmids ensure their inheritance and maintenance during cell division? 

low-copy-number plasmids

What are extragenomic DNA molecules that commonly interact with bacterial genomes

horizontally transferred bacterial plasmids, and bacteriophage genomes