1) some non hemolytic streptococci that normally colonize the human throat produ
ID: 253078 • Letter: 1
Question
1) some non hemolytic streptococci that normally colonize the human throat produce metabolites and inhibit the growth of streptococcus pyogenes a common cause of strep throat. The relationship that exists between the non hemolytic streptococci and the human host is
A-mutualistic
B-commensalistic
C-parasitic
D- antagonistic
E- ammensalistic
2- the LD50 of a pathogenic organism is a measurement of
A- survival value of host population
B- virulence of organism
C- mutualistic characteristics of the strain
D- commensalistic potential of the strain
E- none of the above
Explanation / Answer
1. The correct answer is option A - Mutualistic
Mutualism is a condition in which both the organisms are benefitted. In the give question, non-hemolytic streptococci is obtaining nutrients from human throat and in the meantime it is providing protection against Streptococcus pyogenes. Hence it is a mutualistic interaction.
Commensalism: It is a condition in which both organisms stay together without causing any harm or benifit to each other.
Parasitic: It is a condition in which one organism depends on other organism for food and reproduction.
Antagonistic: It is a condition in which one organism inhibits the growth of other by secreting chemicals like antibiotics.
Ammensalistic: It is similar to symbiotic in which one organism is inhibited and the other is unaffected.
2. The correct answer is option D - None of the above
LD50 is the lethal dose of a drug used to kill 50% of pathogens in a host.
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