Plastid

Definition

Plastids are double-membraned organelles found in the cells of plants and algae. They are involved in the synthesis and storage of food.

5 Must Know Facts For Your Next Test

1. Plastids can differentiate into various forms such as chloroplasts, chromoplasts, and leucoplasts.
2. Chloroplasts, a type of plastid, are crucial for photosynthesis.
3. Plastids contain their own DNA, which is circular and similar to bacterial DNA.
4. The endosymbiotic theory suggests that plastids originated from cyanobacteria through a symbiotic relationship with eukaryotic cells.
5. Leucoplasts are non-pigmented plastids involved in the storage of starches, oils, or proteins.

Review Questions

• What are the primary functions of plastids?
• How does the endosymbiotic theory explain the origin of plastids?
• Name and describe three different types of plastids.

Related terms

Mitochondria: Double-membraned organelles known as the powerhouses of the cell due to their role in energy production through cellular respiration.

Cyanobacteria: A phylum of bacteria that obtain their energy through photosynthesis and are believed to be ancestors of chloroplasts.

Endosymbiosis: A symbiotic relationship where one organism lives inside another; it is a key concept in explaining the origin of certain organelles like mitochondria and plastids.