Which of the following is an intracellular parasite? a. Rickettsia b. Mycobacterium c. Bacillus d. Staphylococcus e. Streptococcus

Hey, everyone. Let's take a look at this question together which of the following best describes obligate intracellular parasites such as rickettsia. Is it answer choice. A they can survive both inside and outside mammalian cells. Answer choice B they rely solely on mammalian cells for reproduction. Answer choice C they can reproduce in any type of host cell or answer choice D they infect mammals but do not reproduced within their cells. Let's work this problem out together to try to figure out which of the following answer choices best describes does obligate intracellular parasites. So in order to solve this question, we have to recall what we have learned about obligate intracellular parasites to determine which of the following answer choices best describes them. And we can recall that obligate intracellular parasites utilize a host in order to grow and reproduce. And since those obligate intracellular parasites have to utilize that host for growth and reproduction. They cannot replicate or complete their life cycle without invading and utilizing the machinery of a host mammalian cell. So that means that the obligate intracellular parasol, rely solely on mammalian cells for growth and reproduction, which tells us that answer choice B is the correct answer. As we note, they do rely solely on mammalian cells for reproduction since they need to utilize that host in order for growth and reproduction. So answer choice B is the only correct answer choice. I hope you found this video to be helpful. Thank you and goodbye.