Explain the endosymbiont hypothesis for the origin of chloroplasts and mitochondria.

Name: Problem 3, Chapter 18: Biology: Life on Earth with Physiology
Uploaded: 2022-02-23T02:14:00-08:00
Duration: 2 min 41 s
Channel: Danielle Aguilar
Description: Explain the endosymbiont hypothesis for the origin of chloroplasts and mitochondria.

step 1 The endosymbiotic hypothesis says that early eukaryotic cells engulfed certain types of bacteria

Explain the endosymbiont hypothesis for the origin of...

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Key Concepts

Mitochondria

Mitochondria are organelles responsible for energy production through cellular respiration. The endosymbiont hypothesis posits that they originated from aerobic bacteria that entered into a symbiotic relationship with early eukaryotic cells. Their possession of a double membrane and a distinct genome supports the idea of an ancestral prokaryote becoming a long-term resident within the host cell.

Chloroplasts

Chloroplasts are organelles that perform photosynthesis in plants and algae. According to the endosymbiont hypothesis, they evolved from photosynthetic bacteria that were engulfed by a eukaryotic ancestor. The presence of their own circular DNA and double membrane structure are key pieces of evidence supporting their endosymbiotic origin.

Endosymbiosis

This is the theory that explains how certain organelles within eukaryotic cells originated from free-living prokaryotes. According to this hypothesis, ancestral eukaryotic cells formed symbiotic relationships with bacteria by engulfing them. Over time, these bacteria became integrated and evolved into permanent internal structures, contributing key metabolic functions to the host cell.

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