Module One Pre-assessment

Question 1

Prokaryotic cells have a membrane-bound nucleus

Answer 1

False

Question 2

One major difference between Gram-positive cell walls and Gram-negative cell walls is that Gram negative cell wall has a thinner layer of peptidoglycan as compared to the Gram-positive cell wall.

Answer 2

True

Question 3

Bacteria that are considered Gram-negative will stain purple as a result of the Gram stain procedure

Answer 3

False

because of the thinner layer of peptidoglycan, Gram-negative bacteria will lose the primary purple stain during the decolorization part of the Gram stain procedure. Gram-negative bacteria will retain the pink/red color of the counterstain.

Question 4

MacConkey Agar is both a differential and selective media

Answer 4

True

MacConkey agar is selective in that it will only grow Gram-negative organisms. It is also differential as it helps to differentiate lactose fermenters from non-lactose fermenting organisms.

Question 5

Staphylococcus aureus can be a common normal flora found in the nose of some individuals

Answer 5

True

Staph. aureus can colonize in the anterior nares of about 30% of healthy individuals. Staph aureus is an opportunistic pathogen that can cause serious disease under the right conditions.

Question 6

Teichoic acid and lipoteichoic acid are unique components of the gram-negative cell wall

Answer 6

False

Teichoic acid and lipoteichoic acid are unique to gram-positive cell walls. Teichoic acid is located on the exterior of the cell and is anchored by peptidoglycan while lipoteichoic acid is attached to the bacterial plasma membrane.

Question 7

In a commensalism relationship, bacteria can colonize human body sites without any beneficial or harmful effect on the individual.

Answer 7

True

Question 8

A bacteria that is a facultative anaerobe requires an environment without oxygen. If oxygen is present this type of bacteria will not grow.

Answer 8

False