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Exam with Solution - Fundamentals of Microbiology | MBIO 3813, Exams of Biology

Material Type: Exam; Professor: Nagle; Class: Fundamentals of Microbiology; Subject: MICROBIOLOGY; University: University of Oklahoma; Term: Spring 2014;

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Exam 1 Copy 1 MBIO 3813-001 Spring 2014
1.
MBIO 3813-001 Fundamentals of Microbiology ANNOTATED KEY KEY KEY KEY ANNOTATED
Lecture Exam 1 WHITE VERSION 7 February 2014 WHITE VERSION
Annotated Fairly thorough explanations this ANNOTATED KEY may be a helpful review at the end
of the semester
Q 13, Q 14,Q. 29, Q 43, Q 46, White Version. Alternative Answers are being accepted. Check
out these questions. Wait for corrected exam scores to be posted.
Question 8 and Question 29: please refer to APPENDIX. A brief introduction to current work on
human gut microbiome.
GREEN VERSION Q 1 = WHITE VERSION Q 26. Questions are identical, displaced by 25 spots
1. On Answer Sheet: NAME: Print Last Name [space] First Name; IDENTIFICATION NUMBER: OU ID. No.
a. Fill-in the corresponding circles with No. 2 pencil. (b. No Birthdate, Gender, or Special Code)
3. Answer the exam questions. Fill in the circles corresponding to your answers. Do this before 9:20. No additional time will be given to do this.
4. Cell Phone Penalty: Mandatory 10 (te n) point penalty if your cell phone is heard ringing or vibrating during the exam. If you expect an urgent call,
identify yourself to the instructor.
5. No electronic devices of any kind are permitted during the exam. No books or notes are permitted.
Backpacks and books must placed at front of classroom. Hats must be worn with the brim at the back.
You may not leave the exam room and come back into it during the exam period.
6. Academic Misconduct: Submission of the Scantron form of your exam indicates agreement with the statement “I have neither given nor received
inappropriate aid in completing this exam .” Using crib sheets, electronic communication, looking at anothe r person’s paper, or other ac tivities which
compromise the integrity of the exam are unacceptable and will be penalized.
7. Versions of Exam: there are two or more versions of this exam. You must answer Question 51 correctly or lose 10 points from the raw score of your
exam.
MULTIPLE CHOICE QUESTIONS. Choose the letter of the best response for each question and darken the corresponding
circle on the Scantron Sheet (No. 2 Pencil!). You may write on these pages; only the Scantron Sheet is graded.
Questions 1 to 3 refer to Figure I on page 1.
1. The organism in Fig. I is a:_______________
A. bacillus B. coccus C. bacilli D. spirochete E. vibrio
Bacillus is a singular word, meaning rod-shaped. Bacilli is plural; there is only one bacillus in the
figure. Coccus is a spherical-shaped microbe, a spirochete is a corkscrew-shaped bacterium, a
vibrio is slightly curved, rather like a comma “,”
2. The organism in Fig. I is a(n):________________ .
A. Protozoan B. “Prokaryote” C. Eukaryote D. Pathogen E. Organelle
A “Prokaryote” is a single-celled microorganism, lacking internal membrane-surrounded organelles
such as the nucleus and mitochondrion/chloroplast and having “loose” DNA, not organized into the
I
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Download Exam with Solution - Fundamentals of Microbiology | MBIO 3813 and more Exams Biology in PDF only on Docsity!

MBIO 3813- 001 Fundamentals of Microbiology ANNOTATED KEY KEY KEY KEY ANNOTATED

Lecture Exam 1 WHITE VERSION 7 February 201 4 WHITE VERSION

Annotated – Fairly thorough explanations – this ANNOTATED KEY may be a helpful review at the end of the semester Q 13, Q 14,Q. 29, Q 43, Q 46, White Version. Alternative Answers are being accepted. Check out these questions. Wait for corrected exam scores to be posted. Question 8 and Question 29: please refer to APPENDIX. A brief introduction to current work on human gut microbiome. GREEN VERSION Q 1 = WHITE VERSION Q 26. Questions are identical, displaced by 25 spots 1. On Answer Sheet: NAME: Print Last Name [space] First Name; IDENTIFICATION NUMBER: OU ID. No. a****. Fill-in the corresponding circles with No. 2 pencil. ( b. No Birthdate, Gender, or Special Code)

3. Answer the exam questions_. Fill in the circles corresponding to your answers. Do this before 9:20. No additional time will be given to do this._ 4. Cell Phone Penalty : Mandatory 10 (ten) point penalty if your cell phone is heard ringing or vibrating during the exam. If you expect an urgent call, identify yourself to the instructor. 5. No electronic devices of any kind are permitted during the exam. No books or notes are permitted. Backpacks and books must placed at front of classroom. Hats must be worn with the brim at the back. You may not leave the exam room and come back into it during the exam period. 6. Academic Misconduct : Submission of the Scantron form of your exam indicates agreement with the statement “I have neither given nor received inappropriate aid in completing this exam.” Using crib sheets, electronic communication, looking at another person’s paper, or other activities which compromise the integrity of the exam are unacceptable and will be penalized. 7. Versions of Exam: there are two or more versions of this exam. You must answer Question 51 correctly or lose 10 points from the raw score of your exam. MULTIPLE CHOICE QUESTIONS. Choose the letter of the best response for each question and darken the corresponding circle on the Scantron Sheet (No. 2 Pencil!). You may write on these pages; only the Scantron Sheet is graded. Questions 1 to 3 refer to Figure I on page 1.

  1. The organism in Fig. I is a:_______________ A. bacillus B. coccus C. bacilli D. spirochete E. vibrio

Bacillus is a singular word, meaning rod-shaped. Bacilli is plural; there is only one bacillus in the

figure. Coccus is a spherical-shaped microbe, a spirochete is a corkscrew-shaped bacterium, a

vibrio is slightly curved, rather like a comma “,”

  1. The organism in Fig. I is a(n):________________. A. Protozoan B. “Prokaryote” C. Eukaryote D. Pathogen E. Organelle

A “Prokaryote” is a single-celled microorganism, lacking internal membrane-surrounded organelles

such as the nucleus and mitochondrion/chloroplast and having “loose” DNA, not organized into the

I II

familiar Eukaryotic cell chromosomes in the mitotic apparatus. The quotation marks are to remind

us that “Prokaryote” is an organism defined by what it does not have.

  1. The structure in Figure I labeled “flagellum” is approximately _______ μm in diameter (thickness) at its base. A. 0.01 μm B. 0.5 μm C. 5 μm D. 50 μm E. 1 Angstrom (10-^4 μm, 10-^10 m)

A bit challenging, this question requires, first, an idea how big the cell is (remember, on order of 1 μm),

and second, a calculation that 0.01 μm is the same as 10 x 10-^9 m; 5 and 50 μm are too big

(although the flagellum of a Eukaryotic cell may be 5 μm or wider in diameter (remember, that

flagellum has microbubles inside and a membrane surrounding it, and it moves in a whip-like

fashion, not a rotary fashion).

1 Angstrom is approximately the size of an atom, much too small for a molecular structure.

The principles behind some of these size-based questions are worth keeping in mind. A red blood cell

is about 8 μm in diameter; a ribosome is about 10 nm in diameter.

  1. On a microscope slide with a sample of pond water microorganisms that has been properly prepared for phase-contrast microscopy, the objects of interest appear as: _______________________under the phase-contrast light microscope. A. intensely glowing, colored objects B. black structures against a light background C. translucent or transparent three-dimensional bodies D. white structures against a dark background

This response is correct because the phase-contrast principle relies upon refraction of the light beam

by particles (structures) inside the cells, rendering a 3-D effect and a transparent cell structure.

  1. SSU refers to:_________. A. Systematic Sequencing of Unknown RNA (used in phylogenetic characterization of an unknown organism) B. The small subunit of the ribosome C. The 16S rRNA D. The size of ribosomes in Bacteria and Archaea

The SSU RNA, is the 16S rRNA in Archaea and Bacteria, 18S rRNA in Eukaryotes.

SSU is the small subunit. SSU rDNA refers to the gene for the SSU RNA.

  1. TRUE // FALSE. In Archaea, the genetic material of the cell is contained in one or just a few chromosomes found in the nucleus. A. True B. False

Key word here is “Nucleus”, which Archaea do not possess.

  1. A lithotroph:_______ A. obtains its energy and electrons from inorganic compounds B. obtains its energy and electrons from organic compounds C. must grow attached to surfaces, i.e. rocks and minerals D. grows only on cellulose

The root “Litho” means rock or mineral, “troph” refers to nutrition, and here means the source of

chemical energy. B is a Heterotroph; C has to do with biofilms, D, is a particular type of

heterotroph.

  1. Recent developments in research on the relationship between humans and their microorganisms have shown that:_____. A. the human gut microflora contains relatively few (less than 700) types of bacteria and single-celled eukaryotes B. the microflora of the gut does not differ very much in its species composition in different people C. late-onset (regressive) autism in children is caused by great changes in the populations of microorganisms inhabiting their intestines [NOT YET SHOWN!!!! Promising Hypothesis but NOT YET KNOWN] D. large changes in the species composition of the gut microflora appear to be correlated with changes in the health or nutritional state of a person E. all of the above are true

A challenging question.

A. Nitrogen B. Oxygen and Carbon C. Sulfur and Carbon D. Oxygen Carbon and Sulfur E. Oxygen, Carbon, Sulfur, and Nitrogen

Will give 1 point for B and C. But look at slides of WInogradsky column and textbook

description: C, O, S cycles occur in a functioning column and the microbiologists had a good

handle on these critical environmental pathways.

Challenging question: Aerobic photosynthesis on the top. Carbon cycle throughout the column.

Sulfur cycle in anaerobic zone (H2S à SO 4 -^2 à H2S , oxidation via light-driven processes,

reduction by sulfate-reducing heterotrophs).

The N cycle isnʼt demonstrated in his column system, although he did work on the ammonia-

using lithotrophs.

  1. Louis Pasteur was the first person to:____________. A. perform vaccinations for smallpox B. use pure culture methods and an animal model of infection to demonstrate the causative agent of a disease C. determine that O 2 was produced from water (H 2 O) during photosynthesis D. separate two optical isomers of an organic compound from a mixture E. observe the production of antibiotics by fungi

A was the Turks, or Lady Montague, and could be the cowpox vaccination developed by Jenner

B was determined by botanists with the lead provided by anaerobic microbiologists, and it was

in mid 1900s before this reaction was recognized.

C YES

D This was Alexander Fleming, although folk-medicine suggested something was produced by

fungi that protected against infection long before his breakthrough.

  1. The component comprising the largest percentage of the dry weight of a typical bacterial cell is:___________. A. DNA B Protein C. RNA D. Lipids E. Small molecule precursors for macromolecules

From reading at very beginning of Ch 3. Protein, 55%, RNA, 20%, Lipids, 10% or so, DNA, 3%

or so, E, 1 to 3% or so. Important point. The largest investment for the cell is to produce protein

  1. TRUE//FALSE. The Mars Rover Curiosity has recently discovered life on Mars.

A. True B. False almost everybody got this. Stay tuned.

  1. _________________renders a three-dimensional image of biological structures on the order of 1 mm in size. A. Scanning EM B. Transmission EM C. Standard fluorescence microscopy D. X-ray crystallography E. Bright field microscopy

Bright-field, TEM, give 2 D images, and size may not be X-Ray,

  1. The phylogeny of the mitochondrion groups it closely with the organisms(s) called the:________ A. Archaea B. Proteobacteria C. Cyanobacteria D. Gram-positive Bacteria E. Eukarya

The SSU RNA sequence of mitochondrion places it squarely in the group known as Proteobacteria.

  1. Fluorescent antibodies can be used to:______________ A. determine the location of specific antigens on the surface of or inside a cell by taking advantage of absorbance properties of the antibodies B. determine the location of specific antigens on the surface of or inside a cell through fluorescent emission C. kill or inactivate foreign cells in tissues or blood D. resolve individual cells that are separated by a distance of 0.2 μm or more

A. the tagged antibodies may absorb photons, but cannot be detected unless they emit light of second

wavelength (absorbance wonʼt resolve the very small dimensions required here). About 1/3 chose this

one. Remember that light emission is whatʼs important.

B. Emission from a point source can be readily detected and localized.

C. They are not used in the animal system for this purpose, but native antibodies (not tagged) of course

do this

D. not typically why fluorescent antibodies are used.

  1. The cell wall of bacteria consists of a specific chemical structure called the:_____________. A. Lipopolysaccharide B. Peptidoglycan C. Pseudopeptidoglycan D. Periplasmic matrix E. Outer membrane

PG from the reading and brief statements in class. A and B and C are in Gram-neg cells, but are not

the cell wall,

C is found in a few Archaea

  1. At a given moment, the cell wall of a Gram-negative bacterial cell is made up of __________molecule(s) of the cell wall structural unit. A. One (1) B. 1,000 C. 25,000,000 D. 2 x 10^11

SubSection heading in Sec 3.4. One molecule at any given instant. It is dynamically changing, by

expanding in area as cell grows, before cell division, at the site of septation.

  1. The Nitrate anion (NO 3 - ):____________. A. can be reduced to NH 3 (NH 4 +) by certain microorganisms at room temperature, or chemically, using catalysts and very high temperatures (on order of 500° C) and pressures (several hundred atmospheres). B. is used as an energy source by lithotrophic microorganisms, as demonstrated by Winogradsky C. can be used as an electron acceptor by certain bacteria and converted to N 2 gas D. can be used as an electron donor by certain bacteria and converted to N 2 gas

This is another challenging question, but we have to become practical chemists. Reaction C is

important in many anaerobic organisms, represents anaerobic respiration, which we will be covering

and which some pathogens utilize.

A refers to what happens to N2.

B. NO 3 -^ is an oxidized substance, has no electrons to be used by lithotrophs. He showed NH 3 - utilizers.

C. TRUE. Last step of N cycle where N 2 is formed from nitrate.

D. again, not electrons available.

A high percentage of us do not have a good understanding of the N cycle and that it has direction.

Also, Nitrogen in animal and plant tissue is part of the nutritional cycle

  1. The size of an object that can be visualized with a light microscope is limited by the:____________ of the microscope.. A. magnification B. resolution C. light intensity D. visual acuity

A refers to size of image, but still cannot resolve structures below a certain size (200 nm in light

microscopy based on absorbance).

  1. Which one of the following statements is not true concerning Bacillus anthracis. A. B. anthracis is the causative agent of anthrax B. B. anthracis can be grown in pure culture C. B. anthracis produces lethal factor, an exotoxin D. B. anthracis is a member of the Bacterial group Firmicutes E. B. anthracis is a Gram-negative bacterial species

Majority got E. A fair number picked D, but B. anthracis is from the Firmicutes.

  1. These cells were:____________bacteria A. Gram-positive B. Gram-negative C. Acid-fast D. Endospore-forming E. One cannot determine which type of bacteria these cells are from this information

This is a question in the real world. Note that Iodine Solution was not used in the staining procedure.

Both Gram-pos and Gram-neg would be decolorized without the use of the Iodine mordant, which

makes a complex with CV which binds to the Gram-pos wall tightly enough not to be removed during

the ethanol treatment.

People tell me this is an example of the kind of close-reading one must do on the MCAT.

  1. The cells on the slide referred to above were:____________________________ by saffranin. A. counterstained B. mutated C. decolorized D. fixed E. dissolved

Most got this one.

  1. The Gram-stain is a(n):__________________stain A. fluorescent B. acid-fast C. differential D. negative E. simple

Most got this one

  1. Robert Koch utilized:__________________staining to identify Mycobacterium tuberculosis in sputum samples. A. endospore B. acid-fast C. Gram D. negative E. simple

This bacterium requires particularly harsh treatment for any stain to penetrate the acid-fast cell wall

structure. Part of the reason M. t. is hard to treat

  1. At the deep sea hydrothermal vents there is a rich biological community, including animals such as the tube worms. H 2 S is the energy source for the life of the animals. The H 2 S is obtained from: A. organic matter coming down from the surface B. photosynthesis at the vent C. hydrogen sulfide (H 2 S) from the outflowing volcanic water D. molecular oxygen (O 2 ) from the surface, dissolved in the water column, reacting with So E. the microorganisms growing in the gut of the tubeworms

The animals require their endosymbiont (gut) bacteria to use the H2S to form cell material which the

animal may digest and use to grow

  1. To resolve structural features in macromolecules to atomic or near-atomic dimensions:_____________. A. X-rays whose wavelength is greater than the atomic dimensions are required B. X-rays whose wavelength is less than the atomic dimensions are required C. a crystal of the macromolecule emits X-rays at specific angles, and detection of the X-rays at those angles permits their location to be calculated and a molecular structure proposed D. UV radiation or long wavelength X-rays projected onto the molecular crystal lead to the emission of shorter wavelength X-rays which pinpoint the atomic locations

The wavelength of X-rays must be of the order of size of the atom, or smaller,

C isnʼt correct because the crystal does not emit the X-rays, but its atoms diffract the X-rays at

characteristic angles.

  1. In a well-established Winogradsky column, most of the microorganisms growing in the layers near very top of the vessel are:_____________. A. aerobes or oxygen-tolerant B. anaerobes C. sulfur-dependent photosynthetic bacteria D. sulfate reducers E. killed by molecular oxygen (O 2 )

Easy to forget that Oxygen (O2) is formed at the top by the photosynthetic cyanobacteria and this is an

aerobic zone

  1. The term proteome represents:____________. A. the translational code of a cell B. the protein synthesizing machinery of a cell

C. the complete set of proteins encoded in the genome of a cell D. the progenitor genome (phylogenetic ancestor) of a contemporary cell

From Ch 3, section 1

  1. __________is (are) a newly-recognized threat to our national public health. A. Extremely-drug-resistant bacteria B. Viruses which infect Archaea or Bacteria C. polio D. smallpox E. dental caries

C, D, not a problem in the U.S., D eradicated in the world. E, not newly recognized; B, not a threat

  1. In the U.S., we are slightly more likely to die from an infectious disease today than were our citizens of about 20 years ago. This is true because:______________________. A. there are vaccines against almost every infectious disease but they are not being used B. we now live in sterile environments, and are not often exposed to infectious microbes; when we are infected with an infectious disease-causing microbe, we are at risk C. bacteria which cause infectious disease in humans are today often resistant to the antibiotics which were once the treatment of choice for an infection D. vaccines, antibiotics, improvements in public health, and understanding of disease mechanisms has reduced the numbers of deaths from infectious disease dramatically, and the statement cannot be true

As noted in class, Answer C is preferred, because a) the word “slightly” applies, and drug-resistance is

an increasing threat to health.

A and B are false. (“sterile” has particular meaning which we need to be aware of.)

D is not ideal answer, but will earn 1 point.

  1. In the case where a certain microorganism has grown on ammonia- and nitrate-free medium containing only glucose and mineral salts, the cells have:____________. A. Fixed Nitrogen B. Respired Nitrogen C. Fixed Nitrate D. Respired Ammonia E. This statement cannot be true, since all organisms require nitrogen

Fixing Nitrogen, Fixing Carbon, are concepts which many of us have trouble understanding, but it refers

to the reduction of more oxidized forms

  1. X-ray structural analysis is carried out on:______________ A. whole cells B. thin sections of cells treated with heavy metal stains C. crystals of a small molecule or macromolecule purified from a cell or macromolecular assembly purified from a cell D. all of the above

Must have regular array of molecules, whose atoms diffract the X-rays.

  1. Which one of the following statements is true? Cyanobacteria are noteworthy because they are:___________. A. in fact algae, known as blue green algae, although the term bacteria not been changed for historical reasons B. often the primary producers of O 2 in aquatic ecosystems C. phylogenetically closely-related to the mitochondrion of eukaryotic cells D. Archaea, and can often be found in volcanic hot springs such as are found in Yellowstone Park as well as in moderate and even Antarctic environments

B is best answer, but will give one point for C , because both Chloroplasts and Cyanobacteria,

Mitochondria and Proteobacteria, are phylogenetically bacteria, and Cp and Cyanobacteria are also

Gram-negative-like. Canʼt overlook the role of Cyanob. In O 2 production!!!

  1. One of the following statements is a corollary to the germ theory of disease:___________. A. Stop the transmission of infectious agent and control a disease B. Sterilize all surfaces, materials, and liquids encountered in daily life and control a disease

Note that there remains MUCH work to be done, but these are some compelling observations that may lead to understanding (and treatment) of a condition which is increasing in frequency. Check out the website and the primary research, peer-reviewed papers posted there.