Question

You have discovered a new single-celled organism. Describe how you would classify it as Bacteria, Archaea, or Eukarya based on the genetics strand of cell biology. Your answer should be a couple sentences long and should include at least one tool or method you would use, the information that tool or method would provide, and what information you would expect to obtain if your organism belonged to each of the above domains.

Answer 1

Single-celled organism as Bacteria: They are microscopic single-celled organisms living in almost every environment on Earth in enormous numbers. They lack membrane-bound nucleus and ranked among the unicellular prokaryotes. Their genetic information resides in sequence of nitrogenous bases in the long molecules of DNA. Their DNA (unlike in eukaryotic cells which lies within the nucleus) is not isolated in a membrane-bound organelle appearing as a long coil which is distributed in the cytoplasm. DNA is present as a single circular chromosome in many of the bacteria, in two chromosomes in some of them, and linear in some cases. Their plasmids (small circular or linear DNA molecules) carries auxiliary information.

Single-celled organism as Archaea: They are single-celled prokaryotic organisms having a complete different cell membrane structure (in comparison to bacteria) which lets them to persist in extreme environmental conditions; they are situated between bacteria and eukarya. The DNA structure of them is similar to genetic structure of bacteria, while simpler than that of eukaryotes. Their DNA lies in single circular plasmid which are coiled at initial stages and straightens out before cell division. The replication and translation of their DNA takes place as it occurs in eukaryotes. When their DNA uncoils, their RNA polymerase (similar to eukaryote RNA polymerase) acts on the strands; their DNA copy creations differ from that of bacteria.

Single-celled organism as Eukarya: Unicellular eukaryotes are the single-celled organisms having defined nucleus, mitochondria and other cell organelles. They consists of phytoplankton (algae), zooplankton, or protozoa (protists, most of which are unicellular). They contain linear chromosomes in multiple numbers having genes much larger than needed to encode the synthesis of proteins (transcription and translation). The major portions of RNA copy of their DNA (genetic information) is rid of, and their mRNA is modified before being translated into protein.