A Scientist Isolates a Microbe from a Contaminated Water Source

question 54

Multiple Choice

A scientist isolates a microbe from a contaminated water source. She thinks that the organism might be a new bacteria that is capable of surviving in the presence of lead, a heavy metal. She makes tubes of growth medium containing either no lead, 0.1 mg lead, 0.25 mg lead, 0.5 mg of lead or 1 mg of lead. She inoculates each tube with the 10 × 103 cells of the new organism and then incubates the inoculated medium at 37oC. After 48 hours, she examines the tubes of medium and finds that there is no growth in any of them. However, she finds that the bacteria grew fine in medium that did not contain any lead. She decides to repeat the experiment using lower concentrations of lead than those she used initially.
-Select which of the following is the hypothesis being tested by the scientist.

• A) The newly isolated microbe can grow in the presence of lead.
• B) The newly isolated microbe is a bacteria.
• C) Lead can be placed into tubes of growth medium.
• D) Bacteria must be incubated for 72 hours before they grow.
• E) Lead is a good nutrient for all bacterial growth.

---

Definitions:

HTML

HyperText Markup Language, the standard markup language for documents designed to be displayed in a web browser, structuring content and multimedia on the internet.

Advertising-Based

A business model or strategy that relies primarily on advertising revenue to sustain its operations and profit margins.

Internet Business Model

A strategy for generating revenue and delivering products or services over the internet.

Google

A global technology company best known for its search engine, but also offering a wide range of Internet-related services and products.