microbio quizzes

sort the following components of the cell envelope of a gram positive cell from the innermost layer (1) to the outermost layer (4). plasma membrane periplasmic space peptidoglycan S-layer or surface layer proteins

1234

Go to the following website (best to copy and paste the link into a browser) Spectra viewer (Links to an external site.) Below or to the right of the graphical plot there is a box labeled "Fluorophores." Type in the box "Lucifer Yellow." The excitation plot is shown by a dashed line and the emission plot is filled. Using the Fluorescence SpectraViewer plot, determine the excitation wavelength for "Lucifer Yellow" that gives the maximum intensity. It is: 300 nm 350 nm 425 nm 480 nm 525 nm 550 nm 625 nm 700 nm

425

a 20 micron microbe a 0.0000002 m microbe a 20 nm virus a 0.002 micron molecule a 0.002 mm microbe

53214

Who is credited with breaking up the "Prokaryotes?"

Carl Woese

Which of the following features are associated with the cell wall of a gram negative cell? Forms a stable complex with crystal violet and iodine that cannot be washed away by ethanol. Is sandwiched between two membranes. Braun's lipoprotein anchors the peptidoglycan to an outer membrane. Is not present in these cells Is composed of repeating disaccharide subunits that form long cables linked together by fatty acid tails. N-acetyl glucosamine and N-acetyl muramic acid are important components. Forms a three dimensional cage structure around the cell. Teichoic acids are rooted in this layer and extend to the outer cell surface.

Correct Answer Is sandwiched between two membranes. Correct! Braun's lipoprotein anchors the peptidoglycan to an outer membrane. Correct! N-acetyl glucosamine and N-acetyl muramic acid are important components. Correct Answer Forms a three dimensional cage structure around the cell.

Next, use the button labeled "Add new fluorophore" to view the excitation/emission patterns of the fluorophore, "CellTrace Far Red." Which of the following are true statements? Check all that apply. (two apply) You should not use these fluorophores to label two different proteins in a cell because you won't be able to distinguish the fluorescent colors. Light that is emitted through fluoresence has longer wavelengths than the excitation wavelengths. Not enough information is provided to distinguish which wavelengths could be used to excite the fluorophores. You can detect Lucifer yellow if you use blue light to excite the fluorophore Lucifer yellow and Cell Trace Far Red could both be detected at 850 nm because that wavelength is in the infrared spectrum.

Correct! Light that is emitted through fluoresence has longer wavelengths than the excitation wavelengths. Correct! You can detect Lucifer yellow if you use blue light to excite the fluorophore

image with A as one dot, B blurry, and C two dots illustrates the ability to resolve two objects as distinct from one another. Which of the following statements are correct. -One way to move from B to C is to increase the angle of light entering the objective lens. -One way to move from B to C is to decrease the angle of light entering the objective lens. -The numerical aperture is larger in B than C. -The numerical aperture is smaller in B than C. -One way to change the numerical aperture is to change the refractive index of the medium through which light moves. -The working distance affects the wavelength.

Correct! One way to move from B to C is to increase the angle of light entering the objective lens. Correct! The numerical aperture is smaller in B than C. Correct! One way to change the numerical aperture is to change the refractive index of the medium through which light moves.

Which of the following is/are not evidence in support of the endosymbiotic theory? Check all that apply Chloroplasts surrounded by two membranes The inner membrane of the mitochondria was derived from the host cell There are introns in both the mitochondrial genetic material and in the nuclear chromosome. The genome in the chloroplast is linear but the eukaryotic chromosome is circular There are different genes in the mitochondria than in the nuclear chromosome

Correct! The inner membrane of the mitochondria was derived from the host cell Correct! There are introns in both the mitochondrial genetic material and in the nuclear chromosome. Correct! The genome in the chloroplast is linear but the eukaryotic chromosome is circular

Microbes are important in cycling which elements throughout Earth's biospheres? carbon nitrogen iron carbon and nitrogen only carbon, nitrogen, and iron

Correct! carbon, nitrogen, and iron

A microbe that is 2 microns... could be E. coli could be a bacterium is not visible by light microscopy could be seen with no magnification could be infected by a bacteriophage

Correct! could be E. coli Correct! could be a bacterium Correct! could be infected by a bacteriophage

How are the long extensions from the main cell shown in the images above proposed to have been involved in the evolution of eukaryotic cells? -These helped a bacterium engulf a Lokiarchaeon and the archaeon became the mitochondrion. -These long extensions are present in most eukaryotic cells. -Extensions like these helped an archaeon related to the Lokiarchaea capture and engulf a bacterium that eventually became the mitochondrion. -Actin-containing bacteria evolved these extensions and the ability to phagocytize allowing development of the eukaryotes. -Heat supplied in hydrothermal vents facilitated evolution of new membrane lipids like those found in these extensions.

Extensions like these helped an archaeon related to the Lokiarchaea capture and engulf a bacterium that eventually became the mitochondrion.

The inside of your oven is probably sterile (free of microbes).

False

Why is the 16S rRNA portion of the bacterial and archaeal genomes used to evaluate their evolutionary relatedness? It is the shortest section of DNA available to sequence. Its function and sequence is highly conserved across these organisms. Its function and sequence show large differences between closely related species. Because it is involved in cell division, changes in nucleotides occur often. The nucleotides used in this part of the genome are structurally different from the rest of the genome.

Its function and sequence is highly conserved across these organisms.

The graph below shows the membrane lipid composition of algae grown in an open pond raceway over a year. There are many different algae present in the raceway. These raceways are used to grow large amounts of algae for bio-production purposes, including biofuels and oils for natural products. The membrane lipids are a great source of these oils. The fatty acids are shown as the different colored bars and are denoted by the C XX:X notation shown in the legend. The C is for Carbon. The first number (XX) is the fatty acid chain length. The second number (X) gives the number of bonds in that fatty acid chain that are unsaturated. This raceway is operated in Arizona. Which of the following statements can be made about these data? -The decrease in C 18:3 in early summer is expected because of warmer outside temperatures. The total abundance of fatty acids is constant over the year. These data suggest an abundance of tetraether monolayers. Fatty acids with a chain length of 16 C make up more than 70% of the total lipid pool. -The composition of algal fatty acids shifts from April through November.

The composition of algal fatty acids shifts from April through November. he decrease in C 18:3 in early summer is expected because of warmer outside temperatures.

A compound microscope has the finest ocular lens manufactured with a magnification of 15X and a poor quality objective lens with a magnification of 40X. Which of the following statements are true? Check all that apply. The minimum distance for this microscope is probably less than 0.2 microns. Correct! The maximum power is 600X. The magnification is 55X. Correct! While the magnification is OK, the image will probably be fuzzy. The working distance is too short.

The maximum power is 600X. While the magnification is OK, the image will probably be fuzzy.

There are microbes that can survive at pH 1

True

In the graph, Vmax is the maximum rate of nutrient uptake per unit of cell carbon. The reason the blue and red lines decrease from left to right is probably because.... -The rate of nutrient uptake decreases over time. -Nutrient uptake rates generally decelerate with increasing nutrient concentrations. -Nitrate (NO3) and ammonium (NH4) cannot diffuse through the plasma membrane. -Nutrient uptake rates decrease with increasing cell size. -Larger cells cannot take up ammonium. -When normalized to cell volume, nutrient uptake rates increase with decreasing cell diameter.

When normalized to cell volume, nutrient uptake rates increase with decreasing cell diameter. Nutrient uptake rates decrease with increasing cell size.

Which of the above naming conventions listed above is/are correct? Check all that apply. A. Bacillus subtilis (italicized) B. B. subtilis C. Bacillus subtilis D. Bacillus Subtilis E. B. subtilis (italicized) F. bacillus subtilis

a and e

The human microbiome consists of all of the human cells in a body. all of the bacterial cells in the human body. all of the bacterial and archaeal cells in the human body. all of the bacteria, archaea, and viruses in the human body. all of the bacteria, archaea, viruses, fungi and other microbes in the human body.

all of the bacteria, archaea, viruses, fungi and other microbes in the human body.

Key features that distinguish bacterial membranes from archaeal membranes include -a phosphate-containing head group links directly to the fatty acid tails -there is phosphate in bacterial membrane lipids and not in archaeal membrane lipids. -an ester links the glycerol to the fatty acid tail in bacterial membrane lipids but not archaeal membrane lipids. -the presence of a bilayer is unique to bacterial membranes. -the presence of integral proteins is unique to bacteria. -keto acyl subunits are the precursor molecules for synthesis of the fatty acids in bacterial membrane lipids but not in archaeal membrane lipids. -the hydrophobic region is on the outer surface of the bilayer in bacteria but not in archaea.

an ester links the glycerol to the fatty acid tail in bacterial membrane lipids but not archaeal membrane lipids. keto acyl subunits are the precursor molecules for synthesis of the fatty acids in bacterial membrane lipids but not in archaeal membrane lipids.

To which domain is the bacterial domain most closely related?

archaea

To which domain is the eukarya domain most closely related?

archaea

recognize archaeal vs bacterial membrane lipids

archaeal have branches and ether

A microbe does not have peptidoglycan, has no nucleus, and is found in soils where it can replicate independently. It is most likely an archaeon a bacterium a eukaryote a virus or bacteriophage an animal cannot exist

archaeon

Which are considered domains in the tree of life? Check all that apply: Bacteria Viruses Protists Eukarya Archaea Prokarya Parasites

bacteria, archaea, eukarya

Microbe B stains purple because ... cocci are Gram positive. the purple color is evidence that the chemical reaction was not complete. Gram positive bacteria do not have peptidoglycan. saffranin reacts with the ethanol to create the dark purple color. crystal violet and iodine complex with the thick layer of peptidoglycan in these cells.

crystal violet and iodine complex with the thick layer of peptidoglycan in these cells.

John Tyndall:

demonstrated that endospores can be destroyed by heat/cool/heat cycles

An organism has been shown to have a membrane-bound nucleus and has a golgi apparatus. It is definitely a bacterium an archaeon a eukaryote a protist a parasite impossible to know with this information

eukaryote

You are observing a culture of Vibrio parahaemolyticus using a compound microscope with an ocular lens that is 10X and total power of 100X. Which of the following will probably improve your ability to resolve details of the image you see. increase the working distance increase the numerical aperture use a stain or dye dehydrate the sample turn off the light so that you create a dark field

increase the numerical aperture use a stain or dye

A microbe that has its own genome, no machinery to translate mRNA into protein, and can replicate so long as it has a host... is a phantom organism is a virus or bacteriophage is an endospore is a bacillus is known only by sequence information must have an S-layer

is a virus or bacteriophage

Saffranin is to the Gram stain as ____ is to the Acid Fast stain. (Fill in the blank with the most appropriate answer below). -ethanol -acid alcohol -carbol fushin -positive charge -negative charge -heat and phenol -methylene blue

methylene blue

Louis Pasteur:

microbes in air need to be trapped by some mechanism to maintain a sterile broth

You shift the objective lens so that now the total magnification is 500X, so the objective lens now in use must be .... Check all that apply of lower power than the one used in question #1 of higher power than the one used in question #1 thinner than the one used in question #1 thicker than the one used in question #1 providing a longer focal length than the one used in question #1 providing a shorter focal length than the one used in question #1

providing a shorter focal length than the one used in question #1 of higher power than the one used in question #1 thinner than the one used in question #1

For years an obscure doctor hailing from Australia's hardscrabble west coast watched in horror as ulcer patients fell so ill that many had their stomach removed or bled until they died. That physician, an internist named Barry Marshall, was tormented because he knew there was a simple treatment for ulcers, which at that time afflicted 10 percent of all adults. In 1981 Marshall began working with Robin Warren, the Royal Perth Hospital pathologist who, two years earlier, discovered the gut could be overrun by hardy, corkscrew-shaped bacteria called Helicobacter pylori. Biopsying ulcer patients and culturing the organisms in the lab, Marshall traced not just ulcers but also stomach cancer to this gut infection. The cure, he realized, was readily available: antibiotics. But mainstream gastroenterologists were dismissive, holding on to the old idea that ulcers were caused by stress. Unable to make his case in studies with lab mice (because H. pylori affects only primates) and prohibited from experimenting on people, Marshall grew desperate. Finally he ran an experiment on the only human patient he could ethically recruit: himself. He took some H. pylori from the gut of an ailing patient, stirred it into a broth, and drank it. As the days passed, he developed gastritis, the precursor to an ulcer: He started vomiting, his breath began to stink, and he felt sick and exhausted. Back in the lab, he biopsied his own gut, culturing H. pylori and proving unequivocally that bacteria were the underlying cause of ulcers. Marshall was once called "the guinea-pig doctor" later talked about his work with the humor and passion of an outsider who has been vindicated. For their work on H. pylori, Marshall and Warren shared the 2005 Nobel Prize in medicine. Today the standard of care for an ulcer is treatment with an antibiotic. And stomach cancer — once one of the most common forms of malignancy — is almost gone from the Western world. Having rid much of the globe of two dread diseases, Marshall later turned his old enemy into an ally. As a clinical professor of microbiology at the University of Western Australia, he worked on flu vaccines delivered by brews of weakened Helicobacter. And in an age when many doctors dismiss unexplained conditions as "all in the head," Marshall's story serves as both an inspiration and an antidote to hubris in the face of the unknown. Question: The microbiology story presented above provides examples of the challenges of endosymbiotic theory fake news science reported on the internet proving Koch's postulates debunking spontaneous generation

proving Koch's postulates

Francesco Redi:

showed that maggots don't develop directly from meat but from eggs laid by flies

Some of the problems associated with Koch's postulates include: -that the presence of an organism is not always associated with the presence of a certain disease. -we do not yet know how to culture all pathogens. -evidence that endosymbiotic theory is incorrect. -it can be challenging to find an acceptable model organism because they don't always present disease in the same way as the original host. -some pathogens do not have a rRNA sequence..

that the presence of an organism is not always associated with the presence of a certain disease. we do not yet know how to culture all pathogens. it can be challenging to find an acceptable model organism because they don't always present disease in the same way as the original host.

Portions of 16S rRNA sequences for 5 bacteria are given above. Which bacterium is expected to be most evolutionarily distant from Bacterium A?

the one with the most differences

true or false: Assuming they have similar volumes, Microbe A (longer) probably has a greater surface area to volume ratio than Microbe B. (circle)

true