Question

Kim and Ron are studying pond water under the microscope and find something swimming along in the water. They catalog the following features: single-celled, large organelle in the center, sack of water near the edge, about 0.5mm long, covered in cilia allowing for movement. Ron is confident that they are looking at a prokaryotic cell and writes this answer: 'This is a prokaryotic cell because it is single-celled, and there is DNA present in the organelle in the middle.' Kim isn't confident about Ron's answer and asks you for help. Is Ron correct or incorrect? How would you identify this cell and justify your answer?

Answer 1

The cell described is a prokaryotic cell with DNA in the organelle in the center.

Step-by-step explanation:

Ron is incorrect. The cell described by Kim and Ron is a prokaryotic cell. Prokaryotic cells are single-celled organisms that lack a nucleus and other membrane-bound organelles.

The presence of DNA in the organelle in the center is a characteristic of prokaryotic cells. In prokaryotes, the DNA is located in a region called the nucleoid.

Other features of the described cell, such as being covered in cilia and having a sack of water near the edge, are commonly found in prokaryotic cells.

Prokaryotic cells lack a nucleus and other membrane-bound organelles, and their genetic material is localized in a region called the nucleoid. The presence of a large organelle in the center of the cell, likely the nucleus, and additional organelles such as a sack of water (vacuole), along with the cell being covered in cilia for movement, are features characteristic of eukaryotes. Furthermore, prokaryotic cells are generally smaller than 0.5mm and do not have organelles like cilia. Therefore, based on the described features, Kim and Ron are likely observing a single-celled organism like a paramecium, which is a protist and a eukaryote