AP BIOLOGY

Detailed explanation-1: -In the example of corals, the host animal is a multicellular cnidarian, and the endosymbiont is a unicellular alga called a dinoflagellate. The host animal serves as a protected environment, providing the alga with a constant supply of nutrients in the form of nitrogen, phosphorus, and sulfur.

Detailed explanation-2: -The small cells (now called endosymbionts) benefited from the relationship by getting a safe home and nutrients. The large cells (now called hosts) benefited by getting some of the organic molecules or energy released by the endosymbionts.

Detailed explanation-3: -An endosymbiont is one organism that lives inside of another one. All eukaryotic cells, like your own, are creatures that are made up of the parts of other creatures. Mitochondria, the important energy generators of our cells, evolved from free-living cells.

Detailed explanation-4: -The first endosymbiotic event occurred when a eukaryotic cell engulfed a prokaryote (SF Fig. 2.4 Step 3). This process, known as primary endosymbiosis, created the mitochondrion. Chloroplasts likely evolved when a eukaryotic cell containing mitochondria engulfed a photosynthetic cyanobacteria cell (SF Fig.