### Origin of Organelle X
Two hypotheses are proposed to explain the evolutionary origin of Organelle X, a compartment found in the cytoplasm of the single-celled eukaryote *Protistum novum*.
*Hypothesis 1*
Organelle X originated through endosymbiosis. An ancestral eukaryotic host cell engulfed a photosynthetic cyanobacterium. Instead of being digested, the bacterium lived symbiotically inside the host, eventually evolving into Organelle X. According to this hypothesis, Organelle X contains its own circular DNA and protein-synthesis machinery similar to that of free-living bacteria.
*Hypothesis 2*
Organelle X originated through membrane invagination. The outer cell membrane of an ancestral eukaryotic cell folded inward and pinched off, creating an internal vesicle that specialized over time into Organelle X. According to this hypothesis, Organelle X does not contain its own DNA; all of its structural and functional proteins are encoded by the cell's nuclear DNA.
Suppose scientists analyze the molecular composition of Organelle X and discover that it contains circular DNA molecules and ribosomes that are sensitive to the same antibiotics that inhibit bacterial translation. Which hypothesis is supported by this new finding?
- AHypothesis 2, because the presence of genetic material inside the organelle confirms that it developed from the host cell's membrane invaginations.
- BBoth Hypothesis 1 and Hypothesis 2, because both hypotheses require the organelle to have its own independent translation machinery to function properly.
- Hypothesis 1, because the presence of circular DNA and bacterial-like ribosomes is consistent with the characteristics of an engulfed symbiotic bacterium.Cevap
- DNeither Hypothesis 1 nor Hypothesis 2, because the sensitivity to antibiotics indicates that the organelle is a modern contaminant rather than an evolutionary structure.