Question

1. pseudomonas aeruginosa is a common pathogen that infects the airways of patients with cystic fibrosis. it does not grow in the absence of oxygen. the bacterium is probably which of the following? a. an aerotolerant anaerobe b. an obligate aerobe c. an obligate anaerobe d. a facultative anaerobe 6. which of the following is the reason jams and dried meats often do not require refrigeration to prevent spoilage? a. low ph b. toxic alkaline chemicals c. naturally occurring antibiotics d. low water activity

Explanation:

Question 5:

Obligate aerobes require oxygen for growth as they use it in aerobic respiration. Since Pseudomonas aeruginosa does not grow in the absence of oxygen, it is an obligate aerobe. Aerotolerant anaerobes can grow in the presence of oxygen but do not require it. Obligate anaerobes are poisoned by oxygen. Facultative anaerobes can grow with or without oxygen.

Question 6:

Jams and dried meats have low water activity. Microorganisms need water for growth and metabolism. A low - water - activity environment inhibits the growth of most spoilage microorganisms, which is why they often do not require refrigeration for short - term storage. Low pH is more characteristic of pickled products. Toxic alkaline chemicals and naturally occurring antibiotics are not the main reasons for the non - spoilage of jams and dried meats without refrigeration.

Answer:

1. B. an obligate aerobe
2. D. low water activity