🦠microbiology review

Archaeplastids

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Archaeplastids are a major group of eukaryotic organisms that include red algae, green algae, and land plants. They are characterized by having plastids that originated from an ancient endosymbiotic event with cyanobacteria.

AP course connection

Topic 5.4: 5.4 Algae

Unit 5

5 Must Know Facts For Your Next Test

  1. Archaeplastids comprise three main groups: Rhodophyta (red algae), Chlorophyta (green algae), and Glaucophyta.
  2. The primary endosymbiotic event that gave rise to Archaeplastids involved a cyanobacterium.
  3. Chlorophyll a is the main photosynthetic pigment found in all Archaeplastids.
  4. Red algae within this group lack flagella, which is unusual among eukaryotes.
  5. Green algae share a common ancestor with land plants, making them crucial for studying plant evolution.
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