BIO 250 STRAIGHTERLINE MICROBIOLOGY
REAL PRACTICE 2025 QUESTIONS ANDcorrect answerS.
The purpose of staining cells on a microscope slide is to ______.
Select one:
- kill them
- secure them to the slide
- enlarge the cells
- add contrast to see them better
- observe motility -correct answer-d. add contrast to see them better
A microbiologist must culture a patient's feces for intestinal pathogens. Which of the following components would likely be present in a selective medium for this purpose?
Select one:
- NaCl
- Sheep red blood cells
- Bile salts
- Thioglycolic acid
- Peptone -correct answer-c. Bile salts
Organisms called parasites are ______.
Select one:
- always harmful to their host
- the decomposers in ecosystems
- always viruses
- free-living -correct answer-always harmful to their host
Trees of life that illustrate the phylogenetic relationships of all organisms were traditionally based on ______; newer methods for determining phylogeny rely on
______.
Select one: 1 / 4
- morphology; nucleic acid sequences
- nucleic acid sequences; morphology
- morphology; virology
- morphology; nutritional requirements
- nucleic acid sequences; microbiomes -correct answer-a. morphology; nucleic
acid sequences
What is the maximum number of electrons in the first energy shell of an atom?
Select one:
- 2
- 4
- 8
- 18
- 32 -correct answer-a. 2
Which of the following is not true about enzymes?
Select one:
- Enzymes are found in all cells.
- Enzymes are catalysts.
- Enzymes participate in the cell's chemical reactions.
- Enzymes can be denaturated by heat and other agents.
- Enzymes have high-energy bonds between phosphates -correct answer-
Enzymes have high-energy bonds between phosphates
NASA has published a list of criteria for identifying fossil bacteria in samples from Mars, as part of a search for evidence of life. Which of the following is good evidence for the presence of bacterial cells?
Select one:
- Cell size of 0.5 to 2 microns
- Three-dimensional organization of cells in a starburst pattern
- Absence of carbon in the material
- No evidence of water in the surrounding mineral -correct answer-a. Cell size of
0.5 to 2 microns 2 / 4
Which type of medium would be the best choice when shipping a sample of bacteria from a clinic to a laboratory for testing?
Select one:
- Transport medium
- Eosin-methylene blue agar
- Blood agar
- Thioglycolate medium -correct answer-a. Transport medium
The orderly arrangement of organisms into a hierarchy of taxa is called ______.
Select one:
- classification
- identification
- nomenclature
- experimentation
- biotechnology -correct answer-a. classification
A microbiologist inoculates Staphylococcus aureus into a culture medium.Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture. What is the most likely explanation?
Select one:
- The microbiologist used too much inoculum.
- The culture was contaminated.
- The incubation temperature was incorrect.
- The culture medium was selective.
- The culture medium was differential. -correct answer-b. The culture was
contaminated.
Disease-causing microorganisms are called ______.
Select one:
- decomposers
- bacteria 3 / 4
- pathogens
- eukaryotes
- fermenters -correct answer-c. pathogens
Which scientific field is involved in the identification, classification, and naming of organisms?
Select one:
- Nomenclature
- Taxonomy
- Phylogeny
- Pathology
- Epidemiology -correct answer-b. Taxonomy
Covalent bonds
Select one:
- result from losing electrons.
- are always polar.
- are always nonpolar.
- result from sharing electrons.
- result from gaining electrons. -correct answer-
Using microbes to detoxify a site contaminated with heavy metals is an example of
______.
Select one:
- biotechnology
- bioremediation
- decomposition
- immunology
- epidemiology -correct answer-bioremediation
Which of the following statements is incorrect regarding protein structure?
Select one:
- / 4