Question

Endosymbiosis Case study& Questions: Brian slumped over his bench in the lab and put his head down in defeat. "What's the matter?" asked his lab mate, Sid. Brian explained that his amoebae had all become infected with bacteria. Frustrated and feeling like his experiments were never going to lead to a Ph.D., he left the lab for the weekend. After the weekend, Brian returned fresh and ready to start his experiments with new amoebae. Although most of his infected amoebae had died, a few were still alive. They looked sick, but at least they were alive. Out of curiosity, Brian decided to see how long it would take for this infection to kill all of his amoebae. Several months later, Brian found that some of his previously infected amoebae and their descendants were no longer sick. Brian figured that the amoebae had fought off the infection and cleared the bacteria. His lab mate Sid, always pushing Brian to think, said, "What evidence do you have to know they fought it off?" 1. What kind of cell is an amoeba? What kind of cell is a bacterium? What makes them different from each other? 2. What are two hypotheses to explain what happened to Brian's amoebae? When Brian looked under the microscope, he found bacteria thriving inside the amoebae. He was surprised and called Sid over to look. "Wow, that's unexpected. I wonder what would happen if you add antibiotics to some of the amoebae." Brian thought about the other experiments he was supposed to be doing, but then decided he was interested enough to continue with this side project. He took Sid's suggestion and added antibiotics to some of the amoebae. When he added antibiotics to the amoebae infected with bacteria, those amoebae died. When Sid heard this news he was excited and began talking about the endosymbiosis hypothesis.

Answer 1

1. Amoeba is eukaryotic cell with its cytoplasm and cellular contents are enclosed within a cell membrane.

Bacterium is prokaryotic cell which lack nucleus and membrane-bound organelles.

Amoeba and bacteria are differentiated based on the organization of cellular components. Amoeba has nucleus and other membrane-bound organelles unlike bacteria.