Question

3. Looking at some pond water under the microscope, you notice an unfamiliar rod-

shaped cell about 200 mm long. Knowing that some exceptional bacteria can be as
big as this or even bigger, you wonder whether your cell is a bacterium or a
eukaryote. how will you decide? if it is not a eukaryote, how will you discover
whether it is a bacterium or an archaeon? [20]​

Answer 1

1. The cells of eucaryotes are characterized by the presence of a nucleus and membrane-bound organelles. Bacteria, on the other hand, do not possess a nucleus or membrane-bound organelles.

2. As bacterial cell walls are made of peptidoglycan (protein and sugars), and archaeal cell walls are composed of polysaccharides (sugars). I would add a lysis solution that separates the cell wall and integral molecules. Then, I could use High-performance liquid chromatography to quantify the chemical composition differences of both walls.

Step-by-step explanation:

1. The cells of eucaryotes are characterized by the presence of a nucleus and membrane-bound organelles. Bacteria, on the other hand, do not possess a nucleus or membrane-bound organelles.

2. Both archaea and bacterial cells lack membrane-bound organelles and nucleus, but they both possess a cell wall. Therefore, if I realize that the cell is definitely a prokaryote and not a eukaryote, then, to determine if it is from an archaeon or bacterium, I would analyze the integrity of their cell walls as bacterial cell walls are made of peptidoglycan (protein and sugars), whereas archaeal cell walls are composed of polysaccharides (sugars).

I could add a lysis solution that separates the cell wall and integral molecules. Then, I could use High-performance liquid chromatography to quantify the chemical composition differences of both walls.

Also, the majority of archaea cannot be cultured within the laboratory setting. So that could also work as another method, except it wouldn't be as reliable as the others.