A ribosome is a tiny part of a cell with the specific job of making protein. All living cells contain ribosomes.

Ribosomes are the organelles responsible for RNA translation, the process of building protein out of amino acids using RNA. The ribosome translates code it finds in strands of messenger RNA, using it to form the new proteins needed by the cell. Microbiologist Richard B. Roberts coined ribosome from the complex scientific phrase "ribonucleoprotein particles of the microsome fraction."

Definitions of ribosome
  1. noun
    any of a group of particles in the cytoplasm of a living cell; they attach to mRNA and move down it one codon at a time and then stop until tRNA brings the required amino acid; when it reaches a stop codon it falls apart and releases the completed protein molecule for use by the cell
    “the ribosome is the site of protein synthesis”
    see moresee less
    type of:
    cell organ, cell organelle, organelle
    a specialized part of a cell; analogous to an organ
Word Family

Test prep from the experts

Boost your test score with programs developed by’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week