BIOS 222 Chapter 11

These flashcards cover key concepts related to protein trafficking and the endoplasmic reticulum as presented in lecture notes.

Endomembrane System

A system of membranes within a cell that includes the endoplasmic reticulum, Golgi apparatus, and other organelles.

ER Signal Sequence

A short peptide chain that directs the nascent protein to the endoplasmic reticulum.

Signal Recognition Particle (SRP)

A ribonucleoprotein complex that recognizes an ER signal sequence and pauses translation.

Translocon

A protein complex in the endoplasmic reticulum membrane that facilitates the translocation of polypeptides into the ER.

Co-translation translocation

The process by which proteins are translocated into the ER while they are being synthesized by ribosomes.

Covalent Modifications

Chemical changes made to proteins after translation, including disulfide bond formation and glycosylation.

Disulfide Bonds

Covalent bonds formed between sulfur atoms of cysteine residues, aiding in protein stability.

Glycosylation

The addition of oligosaccharides to proteins, forming glycoproteins which help in stability and recognition.

Rough ER vs Smooth ER

Rough ER is studded with ribosomes and is the main site for protein synthesis, while Smooth ER is involved in lipid synthesis.

Quality Control Checkpoints

Stages in the endomembrane system that ensure proteins are properly folded and modified before moving onward.