Thylakoids

Definition

Thylakoids are membrane-bound structures found within chloroplasts and cyanobacteria, essential for photosynthesis. They contain chlorophyll and other pigments that capture light energy.

5 Must Know Facts For Your Next Test

1. Thylakoids are the site of the light-dependent reactions in photosynthesis.
2. In cyanobacteria, thylakoids are not organized into stacks like in plants but are dispersed throughout the cell.
3. They play a crucial role in converting solar energy into chemical energy.
4. The thylakoid membrane contains integral proteins that assist in electron transport and ATP synthesis.
5. Grana are stacks of thylakoids found in the chloroplasts of eukaryotic phototrophs, but such organization is absent in prokaryotic phototrophs.

Review Questions

• What is the primary function of thylakoids?
• How do thylakoids differ between cyanobacteria and plant cells?
• What kinds of proteins are found in the thylakoid membrane?

Related terms

Chlorophyll:

A pigment located within thylakoids responsible for capturing light energy.

Photosystem II:

A protein complex within the thylakoid membrane that initiates the light-dependent reactions.

ATP Synthase:

An enzyme located in the thylakoid membrane that synthesizes ATP from ADP and inorganic phosphate during photosynthesis.