MBB 222 Study Guide - Final Guide: Prokaryotic Translation, Signal Peptidase, Signal Peptide

• School: Simon Fraser University
• Department: Molec Biol & Biochem
• Course: MBB 222
• Professor: Adam Barlev

Document Summary

Proteins synthesized on free ribosomes are directed to subcellular locations on the basis of targeting sequences, which specify the nucleus, mitochondria, peroxisomes, and chloroplasts. Proteins synthesized on the er membrane are destined for the plasma membrane or for various membrane compartments in the cytosol. Er-synthesized proteins are often posttranslationally modified with covalently attached lipids and carbohydrates. The translocon protein complex is described in the text. Dna sequences are transcribed into mrna by the enzyme rna polymerase in the nucleus of eukaryotic cells. Rna polymerase synthesizes mrna using ribonucleotides that form complementary base pairs with deoxyribonucleotides in the template strand of dna. The dna sequence of the coding strand is the same as the rna sequence in the mrna, with the exception of uridine replacing thymidine. The mrna is then exported to the cytoplasm, where it is translated into protein. Translation of mrna requires a protein-synthesizing complex, which consists of ribosomes, trnas, and the mrna.