Exam 4: Dynamics of Microbial Growth

Eosin methylene blue agar (EMB) is a selective and differential medium. The dyes in the medium inhibit most Gram-positive organisms. Gram-negative organisms such as the coliforms grow on this medium. Coliforms that are fecal in origin produce colonies with a metallic green color on EMB, while those that are non-fecal produce colorless colonies. You plate a urine sample onto an EMB plate and incubate it. Metallic green colonies develop. From this, you can conclude that 

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur may be considered

The optimal temperature for most human pathogens might be expected to range from

You are in charge of water quality for your city's water treatment plant. Of the methods at your disposal, which will be the most efficient and cheapest method of determining the number of viable bacteria in the water coming out of your plant?

Differential media only allow certain bacteria to grow.

Chemoheterotrophs

In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the

Shigella species and Salmonella species are classified as facultative anaerobes. You know that given this information, the bacteria in your patient's fecal culture will grow best

Shake tubes are used to determine the

Agar replaced gelatin as the gelling (solidifying) agent for media because

Mycobacterium leprae is typically found infecting the ears, toes, and fingers of its host due to its

Organisms that require gaseous oxygen for metabolism are referred to as

Organisms that use organic molecules as their source of carbon are called

A hot tub (with a water temperature of 104°F or 40°C) would most likely contain

During which phase of the bacterial growth curve does a bacterial population become much more resistant to harmful conditions?

Mrs. Thomas comes to the emergency department where you work, complaining of nausea and vomiting, bloody diarrhea, abdominal discomfort and fever. She tells you that she went out to a picnic the previous day, where barbecued chicken was served. Mrs. Thomas is a vegan, so she ate only salad. You think that she likely has salmonellosis, caused by the bacterium Salmonella enterica. However, the presence of blood in her stool causes you concern, and you want to rule out the possibility that patient has shigellosis, caused by Shigella bacterial species. -On HE medium, Shigella species produce blue-green colonies, while Salmonella produces blue-green colonies with a black center. There are two noticeable types of colonies growing on the hektoen enteric (HE) medium in Mrs. Thomas' test. One type of colony is greenish in color. This leads you to conclude that the bacteria in these colonies 

The prefix photo- indicates that an organism will make use of ________ for energy purposes.

Agar

Prokaryotic cells divide by a process known as

The lab technicians culture the sample on Thayer-Martin agar. This complex medium contains 5% sheep blood and a combination of antibiotics. This medium is