1 Transformation: bacteria simply absorb, across their cell membrane and cell wall, DNA that is floating around in the environment. 2  Conjugation: bacteria directly transfer DNA from one bacterium to another through structures called pilli. Transformation: bacteria simply absorb, across their cell membrane and cell wall, DNA that is floating around in the environment. 2  Conjugation: bacteria directly transfer DNA from one bacterium to another through structures called pilli.
Food begins its journey through the digestive system in the mouth, before being pushed by a series of involuntary muscle contractions through the esophagus, then the stomach, and then the small and large intestines.
The esophagus as the entry way to the digestive system. From the back of the mouth (the pharynx) to the top of the stomach, the esophagus is a muscular tube for foods and liquids. Itâs relatively tough and resilient as organs go, built to take most of the material human beings ingest. For the most part, itâs not a very complicated organ.