MICRO EXAM 3

Explain the difference between a biotype and a serotype.

A biotype is a biochemical profile of a particular microorganism, while the serotype is the difference in its surface structures/antigens that will lead to separate immune responses from an organism (characterized by the presence of different antibodies in the individual's serum).

Coccidioidomycosis is

A fungal disease AND caused by a coccidioides species

A microbial mat is thick,dense, highly organized structure composed of distinct layers of different groups of microorganisms. Frequently, they are green, reddish pink, and black, which indicates growth of different microbial groups. Describe why a microbial mat has these distinct layer.

A gradient of sunlight AND oxygen selects for the layers growth if the different microorganisms.

If the GC content of two bacteria is 70%, which of the following is true?

AT content is 30%

Which of the following genera would you most likely find growing in acidic runoff from a coal mine?

Acidithiobacillus

Protozoa are a diverse group of single cell organisms. All of the following are true about protozoa except

All contain chloroplasts and chlorophyll A (Protozoans are not photosynthetic so they don't use light for food)

Certain bacteria use a process called _____ to oxidize ammonium under anaerobic conditions, using nitrite as a terminal electron acceptor.

Anammox

Aflatoxins

Are produced by Aspergillus, are possible carcinogens, may be found in peanuts, are toxins.

Penicillium, the source of the earliest recognized antibiotic (penicillin), is a member of which major fungal group?

Ascomycetes

Diazotrophs are bacteria and archaea that fix N2 into a more biologically available form like ammonia. Which of the following genera is a diazotroph? Here's two hints: 1) you worked with this diazotroph during lab this semester and 2) a species of this genus can be polyploid under some growth conditions, containing up to 80 copies of its chromosome.

Azotobacter

This genus of gram-negative, obligate anaerobe is especially notable in that it is known to parasitize other gram-negative bacteria. It is notable for its velocity, as it can swim as fast as 160 um/s. Although that's a short distance, it's an equivalent to over 100 times their body length per second (imagine swimming at over 100 times your body length per second !!!)

Bdellovibrio

Which of the following insect vector is mismatched with infectious microbe and the disease it causes?

Black fly - Yersinia - Plague

In the late 1970s, _______ and his colleagues at the University of Illinois determined the nucleotide sequence of _____ in a wide variety of organisms. Based on the data, they recognized that prokaryotes could be divided into two major groups. This led to a revolutionary of classification that separates prokaryotes into two domains - Archaea and Bacteria.

Carl Woese, ribosomal RNA

The dormant forms of which of the following genera are the most resistant to environmental extremes?

Clostridium and Bacillus

________ is the process to which nitrogen gas (N2) is reduced to form ammonia (NH3), which can then be incorporated into cellular material. The process, catalyzed by the enzyme complex nitrogenase, require a tremendous amount of energy because N2 has a very stable triple bond.

Nitrogen fixation

Diatoms are diverse group of microscope algae that inhabit aquatic environments. All of the following is true about diatoms except

They posses a holdfast that is strictly used for anchoring (Algae cannot be anchors)

A winogradsky column mimics microbial mats where layering of chemical and physical gradients create distinct microenvironments that select for distinct microbial communities. In general, aerobic photosynthetic bacteria like _____ will at the surface while anaerobic non-photosynthetic bacteria like _____ will live at the bottom.

Cyanobacteria, sulfate-reducing bacteria

The polymerase chain reaction (PCR) is frequently used to detect specific genes. In the correct order, what are the three steps to PCR?

Denaturing, Annealing, and Elongation

Which of the following pairs relate to aquatic environments does NOT match?

Epilimnion - O2 poor

The City of Corpus Christi announce a water boil advisory due to a presence of coliforms in the drinking water. Coliforms are defined as a rod shaped, Gram-negative, non-spore forming bacteria capable of lactose fermentation and the production of gas at 35-37 degrees Celsius. Which of the following genera is part of the coliform group?

Escherichia

Some genes code for proteins that are essential to a cells life. These genes are commonly called housekeeping genes. Examples include genes that encode for Ribosomal proteins and DNA polymerase. These genes accumulate mutations over very long periods of time, as high mutation rates in essential would be lethal. Additionally, these gene sequences provide insights into evolutionary relationships between organisms and therefore, are viewed as ______

Evolutionary chronometers

Gel electrophoresis is a technique used to separate DNA fragments according to size. It uses an electric current move DNA through agarose gel. The DNA migrates through the gel from the positive to negative electrode because DNA itself have an overall positive charge.

False

Geosmins is an organic compound with a distinct earthy flavor and aroma produced by certain eukaryotic algae, and is responsible for the earthy taste if beetroots and a contributor to the stringing earthy scent that occurs in the air when rain falls after a dry spell of weather or when soil is disturbed.

False

When comparing Bacteria, Archaea, and Eukarya, which of the following is not correct?

Fatty acids linked to glycerol by ester linkages can be found in the archaea.

In the early 1870s, the german botanist_______ published several papers on bacterial classification, grouping microorganisms according to shape - spherical, short rods, elongated rods, and spirals.

Ferdinand Cohn

All of the following statements are correct except?

Gel electrophoresis is used to determine the serotype of an organism.

Members of the Enterobacteriaceae

Include E.coli, Enterobacter, Salmonella, and shigella, include many medically relevant bacteria, primarily resides in the intestinal tract of mammals, are facultative anaerobes. (All are correct)

The polymerase chain reaction (PCR) was a revolutionary molecular technique that transformed the field of biotechnology. The person credited with developing PCR was _____, who was awarded the Nobel prize for chemistry 1993.

Kary Mullis

Living organisms can interact with another in a symbiotic relationship. When a relationship between two organisms that benefits both organisms is a positive way, that relationship is called ______. When a relationship benefits one organism in a positive way and does not affect the second organism, that relationship is called ______. When a relationship benefits one organism in a positive way and causes detriment to the relationship that relationship is called ______.

Mutualism, commensalism, Parasitism

All of the following genera are obligate intracellular parasites except.

Mycoplasma

Which of the following IS NOT TRUE about fungi

Numerous species are responsible for disease in humans

In the TAMU-CC BSL-1 laboratories, personal protective equipment (PPE) includes lab coats, gloves, and safety goggles. In the CCNCPHL, BSL-3 laboratory, PPE include which of the following?

One time use Tyvek suite, 2 pair of gloves, 1 pair taped to the sleeves, PAPR hood with Shroud, Scrubs tucked into socks with seams taped (All above are correct)

Biosafety at CCNCPHL involves the prevention of exposure for laboratory personnel, the public, and the environment to infectious agents. Which of the following practices is NOT a component biosafety is a component of biosecurity.

Personnel background checks

The process of PCR involves DNA synthesis. Which of the following is NOT a key ingredient to the PCR process?

Single-stranded RNA primers

Which of the following pairs relate to terrestrial environments does NOT match?

Soil - minimal biodiversity

A patient arrives at the clinic with an unknown infection. As the physician you conduct phenotypic and metabolic tests to determine the bacterial species. The unknown bacterium is Gram-positive, catalase positive, and coagulase positive. Based on the information you can conclude with high confidence that the bacterium is

Staphylococcus aureus

A whole-genome comparison reveals that the average nucleotide identity (ANI) between two bacteria is 96%. What does this say about the two bacteria?

The bacteria are very closely related at the species level.

The term algae refers to simple photosynthetic eukaryotes. Algae differ from other eukaryotic photosynthetic organisms such as land plants because,

They lack an organized vascular system, they have relatively simple reproductive structures, they can be unicellular or multicellular, they lack leaves, roots and stems. (All the above are correct

The Corpus Christi Nueces County Public Health Laboratory (CCNCPHL) houses a BSL-3 laboratory. They are equipped, trained and certified to test samples for range of BSL-3 microorganisms. One is the bacterium responsible for the Black Plague that swept through Europe from 1347 to 1351, killing an estimated 75 to 200 million people. Today, it causes on average 7 clinical cases in the United States per year, according to the Center for Disease Control and Prevention

True

Urine collected from a patient suspected of having a urinary tract infection (UTI) is plated onto MacConkey agar. E-coli, the most common cause of UTIs ferments lactose and therefore forms pink colonies on the agar.

True