Endosymbiosis

What is endosymbiosis?

Endosymbiosis is a theory that explains how certain organelles, like mitochondria and chloroplasts, originated as free-living bacteria that were engulfed by another cell.

Who proposed the endosymbiotic theory?

The endosymbiotic theory was popularized by biologist Lynn Margulis in the 1960s.

What evidence supports the endosymbiotic theory?

Evidence includes similarities between mitochondria/chloroplasts and bacteria, such as double membranes, their own DNA, and ribosomes.

What role do mitochondria play in eukaryotic cells?

Mitochondria are the powerhouse of the cell, responsible for producing ATP through cellular respiration.

What is the function of chloroplasts?

Chloroplasts conduct photosynthesis, converting light energy into chemical energy in plants and some algae.

How did endosymbiosis contribute to the evolution of eukaryotic cells?

Endosymbiosis allowed eukaryotic cells to gain new functionalities, such as aerobic respiration and photosynthesis.

What are some characteristics of mitochondria and chloroplasts that support their bacterial origins?

Both organelles have their own circular DNA and ribosomes, similar to prokaryotes, and replicate independently of the cell's nuclear DNA.

What types of cells contain mitochondria and chloroplasts?

Mitochondria are found in nearly all eukaryotic cells, while chloroplasts are found specifically in plant cells and some protists.

What is a secondary endosymbiosis?

Secondary endosymbiosis is when a eukaryotic cell engulfs another eukaryotic cell that has already undergone primary endosymbiosis.

Give an example of an organism that illustrates endosymbiosis.

An example is the euglena, a protist that contains chloroplasts derived from green algae through endosymbiosis.