Final answer:
Treponema pallidum, the causative agent of syphilis, can grow in the lab and in humans. In the lab, it is typically grown in rabbit testicles or tissue cultures, while in humans, it infects various tissues and organs, leading to the development of syphilis symptoms.
Step-by-step explanation:
Treponema pallidum, the causative agent of syphilis, can grow in the lab and in humans. In the lab, T. pallidum is typically grown in rabbit testicles or tissue cultures. This allows the bacteria to multiply and form colonies that can be studied and analyzed. In humans, T. pallidum infects various tissues and organs, including the skin, mucous membranes, and internal organs, leading to the development of syphilis symptoms. The bacteria can spread through sexual contact or from an infected mother to her baby during childbirth.