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Biology & Life Science
Q:
An endotoxin is
A) the toxic portion of the LPS.
B) a toxin produced within archaeal cells.
C) a toxin known for its primary attack on the epidermis of mammals.
D) a toxin produced in the periplasm of most bacteria.
Q:
The lipopolysaccharide (LPS) layer is found ONLY in the cell walls of
A) gram-positive Bacteria.
B) gram-negative Bacteria.
C) Archaea.
D) Eukarya.
Q:
You have discovered a new coccoid-shaped microorganism with no nucleus, a rigid cell wall, and a diameter of 2 m. Chemical tests reveal that its cell wall does NOT contain peptidoglycan. The new microorganism is
A) most likely a bacterium.
B) most likely a eukaryote.
C) most likely an archaeon.
D) either a bacterium or an archaeon.
Q:
In gram-positive Bacteria, the cell walls are composed mainly of thick ________ layers.
A) protein
B) poly-β-hydroxybutryic acid (PHB)
C) lipopolysaccharides (LPS)
D) peptidoglycan
Q:
You are given an electron micrograph of a bacterial cell. In the micrograph you can clearly see three thin layers of different densities surrounding the cell. Based on the micrograph, you can infer that this cell is ________ and would appear ________ after application of the Gram stain procedure.
A) gram-positive / purple
B) gram-negative / pink
C) gram-positive / pink
D) gram-negative / purple
Q:
Bacteria stain as gram-positive or gram-negative because of differences in the cell
A) wall.
B) cytoplasm.
C) nucleus.
D) chromosome.
Q:
You have discovered a new microorganism, but you want to know if it is a eukaryote or a prokaryote. To investigate this question you prepare a slide with a simple stain and view it with a light microscope with a 40X objective lens and 10X ocular lens. You also prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote). You can see the cells on your control slide, but you don't see cells when you look at your unknown microorganism. What can you conclude from this experiment?
A) The experiment failed to visualize the organism because the stain killed it.
B) Your new unknown microorganism is probably a virus.
C) The cells of the new unknown microorganism may be too small to see with the objective and ocular lenses you used.
D) The new unknown microorganism is probably an archaeon.
Q:
Nutrient transport requires energy because the nutrients must be transported into the cell against a concentration gradient. The energy required for nutrient transport is supplied by
A) ATP.
B) the proton motive force.
C) phosphoenol pyruvate.
D) ATP, the proton motive force, or phosphoenol pyruvate.
Q:
Carrier-mediated transport is necessary when
A) diffusion will not allow adequate amounts of a substance to enter the cell.
B) movement into the cell is against a concentration gradient.
C) the level of nutrients in nature is very low.
D) nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible.
Q:
Some archaea have unique phospholipids in their cytoplasmic membrane that
A) form a monolayer due to the presence of diglycerol tetraethers.
B) form a bilayer due to the presence of sterols.
C) form a stable ring structure due to the presence of crenarchaeol.
D) form a bilayer due to the presence of phosphatidylethanolamine.
Q:
The use of the Gram stain in microbiology is important because it differentiates
A) Bacteria from Archaea.
B) prokaryotic from eukaryotic cells.
C) bacterial cells with different types of cell walls.
D) archaeal cells with different types of metabolism.
Q:
The cytoplasmic membrane could best be described as
A) an impermeable barrier.
B) a passive conduit for intracellular transport.
C) a highly selective permeability barrier.
D) a rigid structure that protects the cell.
Q:
Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates.
A) lower / lower
B) lower / higher
C) higher / lower
D) higher / higher
Q:
The morphology of a cell influences its
A) motility.
B) metabolism.
C) surface-to-volume ratio.
D) motility and surface-to-volume ratio.
Q:
The terms "run" and "tumble" are generally associated with
A) eukaryotic cells.
B) nutrient transport.
C) chemotaxis.
D) clustering of certain rod-shaped bacteria.
Q:
Bacteria with type IV pili
A) possess tubular or stalk-like extensions of their cells.
B) likely exhibit twitching motility.
C) have capsules that promote dehydration.
D) live in aquatic environments.
Q:
An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________.
A) spherical / rod shaped
B) rod shaped / coiled
C) spherical / coiled
D) coiled / spherical
Q:
The explosive chemical trinitrotoluene (TNT) can remain in soils after use and is hazardous to humans. Propose an experiment in which TNT-degrading microorganisms could be isolated for purposes of bioremediation. Also indicate what experimental evidence would be useful to isolate TNT-degrading microorganisms.
Q:
Compare and contrast the functions microbes serve in the digestive systems of both humans and rumens (e.g., cattle).
Q:
Describe two capabilities of microbes that exemplify their dynamic nature.
Q:
Explain why infectious diseases are much less lethal in developed countries than in underdeveloped countries.
Q:
Using specific examples, explain why it is sometimes impossible to satisfy Robert Koch's postulates.
Q:
How would the presence of endospores in Louis Pasteur's nutrient solutions have affected his conclusions about spontaneous generation?
Q:
Explain why only anaerobic bacteria inhabited Earth for the first two billion years of its existence.
Q:
Provide evidence supporting the statement that an ecosystem is controlled by microbial activities.
Q:
Describe beneficial and harmful ways in which microorganisms interact with agricultural crops.
Q:
The text states that antibiotics are derived from microorganisms. What is the benefit to an antibiotic-producing microorganism of producing an antibiotic in its natural habitat?
Q:
Explain how you would use Robert Koch's postulates to determine that Streptococcus pyogenes is the causative agent of streptococcal pharyngitis ("strep throat").
Q:
Compare and contrast the leading causes of death in 1900 with the leading causes of death today. What roles have microbiologists played in the dramatic changes that are evident?
Q:
Explain why microbial cells are excellent models for understanding cell function in higher organisms.
Q:
Compare and contrast the works of Louis Pasteur and Robert Koch in terms of both applied and basic science.
Q:
List three contributions of Ferdinand Cohn to the development of microbiology.
Q:
Microbes were first formally observed during the mid-1600s, but the cell theory was not enunciated until 1839. Write a brief essay explaining why microbiology did not become a formally recognized science until Louis Pasteur's and Robert Koch's time.
Q:
Why is it incorrect to say that an object is partially sterile?
Q:
Explain the nature and function of an enrichment culture.
Q:
Not only do some microorganisms tolerate extremely hot temperatures, some actually require high temperatures for optimal growth.
Q:
Treponema pallidum, a bacterium associated with syphilis, is not considered a pathogen because to date it remains unculturable in the lab, and, therefore, Koch's postulates are unable to be fulfilled.
Q:
Sergei Winogradsky worked with bacteria involved in cycling nitrogen and sulfur.
Q:
Today, the enrichment culture technique developed over a century ago by Martinus Beijerinck remains a feasible approach to discovering bacteria capable of degrading pollutants.
Q:
The discipline of microbiology is intimately associated with biochemistry and genetics, because cells are both biochemical catalysts and genetic coding devices.
Q:
Differentiation occurs only in multicellular organisms.
Q:
The environment in which a microbial population lives is its habitat.
Q:
Both environmental conditions and nutrient resources strongly influence the composition of a microbial community.
Q:
According to our present understanding, each of the three major domains has what is known as its own universal ancestor.
Q:
Metabolism is a unifying characteristic of all cellular organisms.
Q:
All microorganisms require molecular oxygen to carry on life functions.
Q:
Most microorganisms are pathogenic.
Q:
The bubonic plague was caused by Yersinia pestis, a highly pathogenic virus.
Q:
________ was the first to identify a new form of autotrophy in which energy is obtained from oxidizing inorganic compounds called ________.
A) Martinus Beijerinck / heteroautotrophy
B) Martinus Beijerinck / chemolithotrophy
C) Sergei Winogradsky / heteroautotrophy
D) Sergei Winogradsky / chemolithotrophy
Q:
Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants.
A) accelerates the natural cleanup process
B) exploits genetic exchange mechanisms
C) invokes microbial evolution
D) uses chemotaxis of biodegrading microorganisms
Q:
Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as golgi.
A) membranes
B) nuclei
C) membrane-enclosed organelles
D) nuclei and membrane-enclosed organelles
Q:
Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth.
A) algae
B) Archaea
C) cyanobacteria
D) purple sulfur bacteria
Q:
The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________, a subdiscipline of microbiology.
A) applied microbiology
B) biotechnology
C) industrial microbiology
D) molecular microbiology
Q:
________ was the first to describe microorganisms, while ________ was the first person to see bacteria.
A) Antoni van Leeuwenhoek / Robert Hook
B) Antoni van Leeuwenhoek / Robert Koch
C) Robert Hooke / Antoni van Leeuwenhoek
D) Robert Koch / Antoni van Leeuwenhoek
Q:
________ produced by microbial fermentation of glucose from cellulose or cornstarch is becoming a more important component of biofuels in the United States, and specialized ________ are needed to make this a commercially available product.
A) Biodiesel / biotechnologists
B) Biodiesel / industrial microbiologists
C) Ethanol / biotechnologists
D) Ethanol / industrial microbiologists
Q:
The first documented description of a microorganism was of a ________ by ________.
A) bacterium / Ferdinand Cohn
B) fungus / Robert Koch
C) mold / Robert Hooke
D) yeast / Martinus Beijerinck
Q:
Groups of cells derived from a single parent cell by successive cell divisions are known as microbial ________ and which live in environments known as microbial ________.
A) communities / habitats
B) communities / ecosystems
C) populations / habitats
D) populations / ecosystems
Q:
The disease anthrax is caused by the pathogenic bacterium ________, which produces heat-resistant structures known as ________.
A) Azotobacter chroococcum / endospores
B) Azotobacter chroococcum / plasmids
C) Bacillus anthracis / endospores
D) Bacillus anthracis / plasmids
Q:
Microbial cells first evolved on Earth approximately ________ billion years ago.
A) 1.6 to 1.8
B) 3.8 to 3.9
C) 5.4 to 5.6
D) 7.0 to 7.2
Q:
Major classes of macromolecules present in all living microorganisms include
A) amino acids, carbohydrates, lipids, and nucleic acids.
B) cell wall, cytoplasmic membrane, nucleoid, and ribosomes.
C) genes, proteins, and vitamins.
D) inorganic and organic compounds.
Q:
Microbial biochemistry involves the discovery of microbial ________ and the ________ they perform.
A) biomolecules / functions
B) enzymes / catalyses
C) metabolic pathways / reactions
D) biomolecules, enzymes, and metabolic pathways / functions
Q:
Bacillus anthracis deficient in its ability to differentiate would not be able to
A) chemotax towards growth substrates.
B) create vessicles.
C) form endospores.
D) grow without additional supplemented nutrients.
Q:
Robert Koch received the 1905 Nobel Prize in Physiology or Medicine for
A) developing a smallpox vaccination.
B) identifying Mycobacterium tuberculosis as the causative agent of tuberculosis.
C) making an effective rabies vaccine.
D) developing a smallpox vaccination, identifying Mycobacterium tuberculosis as the causative agent of tuberculosis, and making an effective rabies vaccine.
Q:
An ecosystem includes ________ along with ________.
A) macroorganisms / microorganisms
B) living organisms / their chemical and physical environments
C) pathogenic organisms / non-pathogenic organisms
D) single celled organisms / multi-cellular organisms
Q:
The process whereby microorganisms are used to help clean up pollution created by human activities is known as
A) bioaugmentation.
B) biodegradation.
C) bioengineering.
D) bioremediation.
Q:
Cyanobacteria and purple bacteria both obtain energy from light. However, only the ________ are capable of releasing ________.
A) cyanobacteria / organic compounds
B) cyanobacteria / oxygen
C) purple bacteria / organic compounds
D) purple bacteria / oxygen
Q:
Some microorganisms can undergo ________ in which various cell types can become specialized and arise from one parent cell type.
A) differentiation
B) genetic exchange
C) maturation
D) mutagensis
Q:
A microbial cell's membrane is considered ________, because its internal constituents are maintained within the cell. However, it also imports and exports other molecules in response to its environment.
A) differential
B) microselective
C) rigid
D) semipermeable
Q:
Which scientific objective is LEAST related to microbial genetics?
A) determining the ancestral origin of a recently discovered bacterium
B) identifying mutations in a bacterial population
C) identifying quorum sensing interactions among bacteria
D) manipulating a microorganism for bioremediation
Q:
The structure that confers structural strength on the cell is known as the
A) cytoplasmic membrane.
B) cell wall.
C) ribosome.
D) cytoplasm.
Q:
Microbial ecology is the study of
A) microbial processes in the rhizosphere that benefit plant growth.
B) the diversity and activities of microorganisms.
C) the grouping and classifying of microorganisms.
D) microorganisms in their natural environments.
Q:
Microorganisms play key roles in the cycling of important nutrients in plant nutrition, particularly those of
A) carbon.
B) nitrogen.
C) sulfur.
D) carbon, nitrogen, and sulfur.
Q:
Louis Pasteur's most famous success was his work on
A) Mycobacterium tuberculosis.
B) the rabies vaccine.
C) optical isomers.
D) cultivation of E. coli.
Q:
Mycobacterium tuberculosis is very difficult to stain because of the
A) presence of ribosomes in the cytoplasm.
B) location of the DNA within the cell.
C) large amounts of a waxy lipid present in its cell wall.
D) lack of a cell wall.
Q:
The science of grouping and classifying microorganisms is known as
A) microbial physiology.
B) proteomics.
C) metabolomics.
D) microbial systematics.
Q:
Robert Koch contributed to the field of microbiology by being the first person to
A) develop the tuberculin test.
B) formulate four postulates for definitively linking a specific microorganism to a specific disease.
C) use agar as a solidifying agent in growth media.
D) develop the tuberculin test, formulate four postulates for definitively linking a specific microorganism to a specific disease, and use agar as a solidifying agent in growth media.
Q:
Microbial control in wastewaters would most logically be a part of
A) microbial genetics.
B) aquatic microbiology.
C) medical microbiology.
D) bacterial energetics.
Q:
Developments in the fields of immunology and medical microbiology were practical extensions of the work of
A) Sergei Winogradsky.
B) Antoni van Leeuwenhoek.
C) Joseph Lister.
D) Robert Koch.
Q:
Chemolithotrophy involves
A) oxidation of organic compounds.
B) oxidation of inorganic compounds.
C) reduction of organic compounds.
D) metabolic autotrophy.
Q:
Martinus Beijerinck was the first to isolate
A) green algae.
B) certain nitrogen-fixing root nodule bacteria.
C) certain sulfate-reducing bacteria.
D) green algae, certain nitrogen-fixing root nodule bacteria, and certain sulfate-reducing bacteria.