exam 1 questions for review : ch 1,3,6

A lab supervisor orders bacterial cultures that have been lyophilized. Lyophilization can be described as _________. a. freeze-drying b. deep-freezing c. refrigeration d. pickling

a

A scientist discovers a microbe growing on the teeth of a patient. This microbe lacks a nucleus, and chemical examination reveals it also lacks the chemical peptidoglycan. The scientist determines that the microbe is a(n) ______. a. bacterium b. archaeon c. eukaryote d. animalcule

a

Bacterial flagella are __________________. a. anchored to the cell by a basal body b. composed of hami c. surrounded by an extension of the cytoplasmic membrane d. composed of hollow microtubules

a

Barophiles _________. a. cannot cause diseases in humans b. live at normal barometric pressure c. die when put under high pressure d. thrive in warm air

a

In a defined medium, _________. a. the exact chemical composition of the medium is known b. agar is available for microbial nutrition c. blood may be included d. organic chemicals are excluded

a

Of the following investigators, who first promulgated the theory of abiogenesis? a. Aristotle b. Pasteur c. Needham d. Spallanzani

a

Quorum sensing is _________. a. the ability to respond to changes in population density b. a characteristic allowing secretion of a matrix c. dependent on direct contact among cells d. associated with colonies in broth culture

a

Which of the following is not a function of a glycocalyx? a. It forms pseudopods for faster mobility of an organism. b. It can protect a bacterial cell from drying out. c. It can hide a bacterial cell from other cells. d. It can allow a bacterium to stick to a host.

a

Which of the following is the most toxic of these forms of oxygen? a. hydroxyl radical b. peroxide anion c. superoxide radical d. singlet oxygen

a

Which of the following microorganisms is not eukaryotic? a. a bacterium b. a yeast c. a mold d. a protozoan

a

Which of the following statements is true? a. The cell walls of bacteria are composed of peptidoglycan. b. Peptidoglycan is a fatty acid. c. Gram-positive bacterial walls have a relatively thin layer of peptidoglycan anchored to the cytoplasmic membrane by teichoic acids. d. Peptidoglycan is found mainly in the cell walls of fungi, algae, and plants.

a

A certain positively charged chemical occurs at a higher concentration outside a cell than inside it. What is the more likely way for this chemical to enter the cell? a. active transport b. facilitated diffusion c. osmosis d. pinocytosis

b

A microbiologist is growing various microbes that require growth factors. Which of the following is not a growth factor? a. cholesterol b. water c. vitamin d. heme

b

A microbiologist working for the pulmonary unit of a hospital is growing some microaerophiles. They grow best with a high concentration of carbon dioxide in addition to a low level of oxygen. Such microbes can be described as _________. a. aerotolerant b. capnophiles c. facultative anaerobes d. fastidious

b

A microbiology student wants to grow microbes in a Petri plate on the laboratory table. Which of the following can grow? a. an anaerobic bacterium b. aerobic bacteria c. viruses on the agar surface d. all of the above

b

A scientist studying bacterial inclusions might find __________________. a. DNA b. sulfur globules c. dipicolinic acid d. tubulin

b

John Needham showed that living microbes appeared in vials of boiled infusions of plant material. He concluded that these microbes arose spontaneously as a result of the effects of a "life force" in the infusions. About a hundred years later, Pasteur disproved Needham by ______. a. fermenting the life force b. boiling similar infusions longer c. developing pasteurization d. immunizing the vials

b

The enzyme superoxide dismutase _________. a. causes hydrogen peroxide to become toxic b. detoxifies superoxide radicals c. neutralizes singlet oxygen d. is missing in aerobes

b

Which cellular structure is important in classifying a bacterial species as either Gram-positive or Gram-negative? a. flagella b. cell wall c. cilia d. glycocalyx

b

Which of the following is most useful in representing population growth on a graph? a. logarithmic reproduction of the growth curve b. a semilogarithmic graph using a log scale on the y-axis c. an arithmetic graph of the lag phase followed by a logarithmic section for the log, stationary, and death phases d. None of the above would best represent a population growth curve.

b

Which of the following statements concerning growth and reproduction is false? a. Growth and reproduction may occur simultaneously in living organisms. b. A living organism must reproduce to be considered alive. c. Living things may stop growing and reproducing yet still be alive. d. Normally, living organisms have the ability to grow and reproduce themselves.

b

"A laboratory scientist moves a sterile inoculating loop several times across an agar surface in a culture dish, thinning a sample and isolating individual cells." This statement describes which of the following? a. broth culture b. pour plate c. streak plate d. dilution plate

c

A Coulter counter is a(n) _________. a. statistical estimation using 15 dilution tubes and a table of numbers to estimate the number of bacteria per milliliter b. indirect method of counting microorganisms c. device that directly counts microbes as they pass through a tube in front of an electronic detector d. grid used to directly count microbes stained with fluorescent dyes

c

A Gram-negative cell is moving uric acid across its cytoplasmic membrane against the chemical's concentration gradient. Which of the following statements is true? a. The exterior of the cell is probably electrically negative compared to the interior of the cell. b. The acid probably moves by a passive means such as facilitated diffusion. c. The acid moves by an active process such as active transport. d. The movement of the acid requires phagocytosis.

c

A laboratory scientist is making some solid microbiological growth media. She will likely use a chemical derived from ______. a. bacteria b. fungi c. alga d. eprotozoa

c

A researcher silences the gene for dipicolonic acid; in doing so, she would affect the cell's ability to make __________________. a. Gram-positive archaeal walls b. cytoplasmic membranes in eukaryotes c. endospores d. Golgi bodies

c

A scientist discovers a cell with a arrangement of microtubules. She realizes the cell likely has ______________. a. archaeal flagella b. bacterial flagella c. eukaryotic flagella or cilia d. pili or hami

c

Which of the following is most associated with diffusion? a. symports b. antiports c. carrier proteins d. endocytosis

c

Which of the following is not associated with prokaryotic organisms? a. nucleoid b. glycocalyx c. cilia d. circular DNA

c

Which of the following scientists hypothesized that a bacterial colony arises from a single bacterial cell? a. Antoni van Leeuwenhoek b. Louis Pasteur c. Robert Koch d. Richard Petri

c

Which of the following terms best describes an organism that cannot tolerate the presence of oxygen? a. obligate aerobe b. facultative aerobe c. obligate anaerobe d. facultative anaerobe

c

A scientist seeking to study archaea could find them in ______. a. acidic hot springs b. swamp mud c. Great Salt Lake d. all of the above

d

A scientist who studies the role of microorganisms in nature is a(n) ______. a. genetic technologist b. earth microbiologist c. epidemiologist d. environmental microbiologist

d

Endospores __________________. a. are reproductive structures of some bacteria b. occur in some archaea c. can cause shock, fever, and inflammation d. are dormant, resistant cells

d

Gram-positive bacteria __________________. a. have a thick cell wall, which retains crystal violet dye b. contain teichoic acids in their cell walls c. typically appear purple after Gram staining d. all of the above

d

Organisms that preferentially thrive in icy waters are described as _________. a. barophiles b. thermophiles c. mesophiles d. psychrophiles

d

Scientists can measure the number of fecal bacteria in a water sample to help determine the safety of the water for drinking. Which of the following methods would be best for indirectly estimating the number of bacteria in the stream? a. dry weight b. turbidity c. viable plate counts d. membrane filtration

d

The laboratory of Robert Koch contributed which of the following to the field of microbiology? a. simple staining technique b. use of Petri dishes c. first photomicrograph of bacteria d. all of the above

d

Which of the following is true of Svedbergs? a. They are not exact but are useful for comparisons. b. They are abbreviated "sv." c. They are prokaryotic in nature but exhibit some eukaryotic characteristics. d. They are an expression of sedimentation rate during high-speed centrifugation.

d

Which of these scientists first hypothesized that medical personnel can infect patients with pathogens? a. Florence Nightingale b. Joseph Lister c. John Snow d. Ignaz Semmelweis

d