Concept 26.4

Q1: What evidence supports the hypothesis that mitochondria preceded plastids in the evolution of eukaryotic cells?

A1: All eukaryotes have mitochondria or genetic remnants of these organelles, but not all eukaryotes have plastids.

Q2: How is a eukaryotic cell like a chimera?

A2: The chimera of Greek mythology contained parts from different animals. Similarly, a eukaryotic cell contains parts form various prokaryotes; mitochondria from one type, and bacterium, plastids from another type, and a nuclear genome from parts of the genomes of these endosymbionts and at least one other cell.