In: Biology
1. Virulence factors are those attributes of microorganisms that enable them to cause damage in a host. Some bacteria produce hemolysins. Explain what hemolysins are, and indicate whether they would be classified as virulence factors. Explain why, or why not. 1 point
2. Earl says that his unknown is an anaerobe, because results of his thioglycollate tube indicate the organism is a facultative anaerobe. A. Explain how a thioglycolate tube can determine aerotolerance. B. Explain what a facultative anaerobe is, and comment on Earl’s conclusion. 1 point
Ans-1) Hemolysins are lipids and proteins that cause lysis of the red blood cells by destroying their cell membrane. They would be classified as virulence factors as they are toxins that have the capacity to destroy red blood cells and damage the human tissues.
Ans-2)A) Thioglycolate tubes contain thioglycolate broth which is used to determine the growth characteristics of various bacteria types based on their oxygen requirements. Facultative anaerobic bacteria show even growth throughout the broth(medium). Strictly anaerobic bacteria grow at the bottom of the tube in the broth. Whereas, strictly aerobic bacteria grow towards the surface of the broth in the tube. This is how a thioglycolate tube can determine aerotolerance.
Ans-2B) A facultative anaerobe is an organism that produces ATP by aerobic respiration in the presence of oxygen but can switch to fermentation if oxygen is absent.
Earl's conclusion that the unknown organism is a facultative anaerobe proves that the organism showed even growth throughout the thioglycolate broth which only happens in case of facultative anaerobes.