Microbiology Ch. 6 Questions And Answers.
Microbes have very narrow optimum temperature ranges. Which of the following classifications of microbes
... [Show More] are most likely to cause human disease, based on temperature requirements?
hyperthermophiles
thermophiles
mesophiles
psychrophiles - CORRECT ANSWER Mesophiles - The temperature range of mesophiles overlaps that of normal human body temperature, allowing the greatest growth.
Which of the following statements accurately describes the culture media necessary for growing Clostridium tetani?
A complex medium is one whose exact chemical composition is known.
Nutrient agar contains ingredients that combine with oxygen and remove it, creating an anaerobic environment.
A chemically defined medium is one made up of extracts such as those from yeasts, meat, or plants whose exact chemical composition may vary slightly.
Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment. - CORRECT ANSWER Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment.
Bacteria that can grow in the presence or absence of oxygen (O2) are called __________.
facultative anaerobes
obligate anaerobes
microaerophiles
obligate aerobes - CORRECT ANSWER Facultative anaerobes - are able to use oxygen if it is present but also to grow in the absence of oxygen, although with decreased efficiency.
E - CORRECT ANSWER Which tube shows the expected growth pattern for a microaerophile?
Which enzyme catalyzes the reaction: O2- + O2- + 2H+ → H2O2 + O2?
superoxide dismutase
oxidase
catalase
peroxidase - CORRECT ANSWER superoxide dismutase
The term aerotolerant anaerobe refers to an organism that:
is killed by oxygen.
uses oxygen or grows without oxygen.
requires more oxygen than is present in air.
requires less oxygen than is present in air.
does not use oxygen but tolerates it. - CORRECT ANSWER does not use oxygen but tolerates it.
A culture medium on which only gram-positive organisms grow and a yellow halo surrounds Staphylococcus aureus colonies is called a(n)
selective medium.
differential medium.
enrichment culture.
selective and differential medium.
differential and enrichment culture. - CORRECT ANSWER selective and differential medium.
A culture medium consisting of agar, peptone, and beef heart is a
reducing medium.
selective medium.
chemically defined medium.
differential medium.
complex medium. - CORRECT ANSWER complex medium. [Show Less]