key term - Ribosomes

Definition

Ribosomes are molecular machines within cells that synthesize proteins by translating messenger RNA (mRNA) into polypeptide chains. They are composed of ribosomal RNA (rRNA) and proteins, and they exist in both prokaryotic and eukaryotic cells.

5 Must Know Facts For Your Next Test

1. Ribosomes can be found either floating freely in the cytoplasm or attached to the endoplasmic reticulum, forming rough ER.
2. Prokaryotic ribosomes (70S) are smaller than eukaryotic ribosomes (80S), with 'S' standing for Svedberg unit, a measure of sedimentation rate during centrifugation.
3. Ribosomes play a critical role in the central dogma of molecular biology, which describes the flow of genetic information from DNA to RNA to protein.
4. Antibiotics like tetracyclines and aminoglycosides target bacterial ribosomes, inhibiting protein synthesis and thus serving as effective antibacterial drugs.
5. Mutations affecting ribosomal function can lead to diseases known as ribosomopathies.

Review Questions

Related terms

Translation:

The process by which ribosomes synthesize proteins using mRNA as a template.

Endoplasmic Reticulum:

A network of membranes within the cell involved in protein and lipid synthesis; rough ER is studded with ribosomes.

mRNA:

Messenger RNA that carries genetic information from DNA to the ribosome for protein synthesis.