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.
Esophagus. The esophagus is a small hose-like tube, which connects the mouth to the stomach. As it leaves the mouth, the esophagus follows a straight path through the neck and chest, passing near the heart through the diaphragm muscle and finally entering the stomach.The walls of the esophagus are composed of muscles, which move in wave-like contractions to push food into the stomach.s it leaves the mouth, the esophagus follows a straight path through the neck and chest, passing near the heart through the diaphragm muscle and finally entering the stomach. The walls of the esophagus are composed of muscles, which move in wave-like contractions to push food into the stomach.