Cisternae

Definition

Cisternae are flattened, membrane-bound compartments that make up the Golgi apparatus and endoplasmic reticulum. They play a critical role in modifying, sorting, and packaging proteins and lipids for secretion or use within the cell.

5 Must Know Facts For Your Next Test

1. Cisternae in the Golgi apparatus have a distinct polarity with cis, medial, and trans regions.
2. Each cisterna is filled with specific enzymes that modify protein cargo as it moves through the stack.
3. In the rough endoplasmic reticulum (RER), cisternae are studded with ribosomes that synthesize proteins.
4. Cisternae are dynamic structures that can change shape and size depending on cellular needs.
5. The number of cisternae in the Golgi apparatus can vary between cells based on their secretory activity.

Review Questions

• What are cisternae and where are they found in eukaryotic cells?
• How do cisternae contribute to protein processing in the Golgi apparatus?
• What distinguishes cisternae of the rough endoplasmic reticulum from those of the smooth endoplasmic reticulum?

Related terms

Golgi Apparatus: An organelle composed of stacked cisternae involved in modifying, sorting, and packaging proteins and lipids.

Endoplasmic Reticulum: A network of membranes within the cytoplasm of eukaryotic cells involved in protein and lipid synthesis.

Ribosome: A molecular machine located on rough ER responsible for synthesizing proteins by translating mRNA.