Membrane-bound ribosomes

Definition

Membrane-bound ribosomes are ribosomes attached to the cytoplasmic side of the endoplasmic reticulum or the nuclear envelope. They play a crucial role in synthesizing proteins destined for secretion, insertion into membranes, or lysosomes.

5 Must Know Facts For Your Next Test

1. Membrane-bound ribosomes are primarily associated with the rough endoplasmic reticulum (RER).
2. They synthesize proteins that are usually exported from the cell or incorporated into the cell’s membrane.
3. The attachment of ribosomes to the ER gives it a 'rough' appearance under a microscope.
4. Proteins synthesized by membrane-bound ribosomes often undergo post-translational modifications within the ER.
5. Membrane-bound ribosomes differ from free ribosomes, which float freely in the cytoplasm and synthesize proteins that function within the cytosol.

Review Questions

Related terms

Endoplasmic Reticulum (ER):

A network of membranous tubules within eukaryotic cells, involved in protein and lipid synthesis.

Free Ribosome: Ribosomes that float freely in the cytoplasm and synthesize proteins for use within the cell.

Post-Translational Modification: Chemical changes to a protein after it has been synthesized, often occurring in the ER for membrane-bound proteins.