Ribosome

From CellBiology

Introduction

Chloroplast Ribosome

Cytoplasmic structure formed from RNA and proteins that assembles to synthesise proteins. Ribosomes may be either free in the cytoplasm or attached to the endoplasmic reticulum, forming rough endoplasmic reticulum.

Ribosome Structure

  • All RNA components mRNA, rRNA and tRNA come together in this structure
  • two ribosome types with identical structure
  • different locations
  • free and membrane bound
    • Free in cytoplasm
    • Bound to endoplasmic reticulum

Ribosome Function

  • Protein Synthesis
  • complexes where RNA sequences are converted to amino acid (aa) sequences
  • Codons 3 NTPs = 1 AA
    • AA incorporated at 20/sec
    • average sized protein takes 20-60 seconds to assemble
  • Synthesis from amino- to carboxy- terminal of protein
  • many ribosomes can bind 1 mRNA

Polyribosomes

  • polyribosomes or polysomes are the EM visible granules
  • many ribosomes bound to a single mRNA
  • single ribosome covers a 54bp mRNA region
  • the synthesised single amino acid chain can then be "modified"
    • in the cytoplasm or in specialised organelles
  • Protein Modification/Function

References

Textbooks

Essential Cell Biology

  • Chapter 14 Intracellular Compartments and Transport

Molecular Biology of the Cell

Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002

Molecular Cell Biology

Lodish, Harvey; Berk, Arnold; Zipursky, S. Lawrence; Matsudaira, Paul; Baltimore, David; Darnell, James E. New York: W. H. Freeman & Co.; c1999

The Cell- A Molecular Approach

Cooper, Geoffrey M. Sunderland (MA): Sinauer Associates, Inc.; c2000

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Books

PubMed

  • PubMed is a service of the U.S. National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals for biomedical articles back to 1948. PubMed includes links to full text articles and other related resources. PubMed
  • PubMed Central (PMC) is a free digital archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health (NIH) in the National Library of Medicine (NLM) allowing all users free access to the material in PubMed Central. PMC
  • Online Mendelian Inheritance in Man (OMIM) is a comprehensive compendium of human genes and genetic phenotypes. The full-text, referenced overviews in OMIM contain information on all known mendelian disorders and over 12,000 genes. OMIM
  • Entrez is the integrated, text-based search and retrieval system used at NCBI for the major databases, including PubMed, Nucleotide and Protein Sequences, Protein Structures, Complete Genomes, Taxonomy, and others Entrez

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Reviews

  • The ribosome returned Peter B Moore J Biol. 2009; 8(1): 8. Published online 2009 January 26. doi: 10.1186/jbiol103. PMID: 19222865
  • Insights into protein biosynthesis from structures of bacterial ribosomes. Berk V, Cate JH. Curr Opin Struct Biol. 2007 Jun;17(3):302-9. Review. PMID: 17574829
  • Ribosome structure. The ribosome in action. Dahlberg AE. Science. 2001 May 4;292(5518):868-9. PMID: 11341282
  • A structural understanding of the dynamic ribosome machine. Steitz TA. Nat Rev Mol Cell Biol. 2008 Mar;9(3):242-53. Review. PMID: 18292779

Articles

Terms

internal ribosomal entry site (IRES)

Links

Wikipedia Ribosome

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