Ribosomes are cellular machines that synthesize proteins. They act as the "factories" where the genetic information encoded in messenger RNA (mRNA) is translated into a chain of amino acids, which then fold into functional proteins.
Here's a breakdown of how ribosomes work:
- Read mRNA: Ribosomes move along the mRNA molecule, reading the sequence of codons, which are three-nucleotide units that specify a particular amino acid.
- Recruit tRNA: Each codon is recognized by a specific transfer RNA (tRNA) molecule, which carries the corresponding amino acid.
- Form peptide bonds: Ribosomes link the amino acids together in the order specified by the mRNA sequence, creating a polypeptide chain.
- Release protein: Once the ribosome reaches a "stop" codon in the mRNA, the completed polypeptide chain is released from the ribosome and folds into a functional protein.
Ribosomes are essential for all living organisms, as proteins perform a wide variety of functions in cells, including:
- Enzymes: Catalyzing biochemical reactions
- Structural components: Providing support and shape to cells
- Hormones: Regulating various bodily functions
- Antibodies: Defending against infections
Ribosomes can be found both free in the cytoplasm and bound to the endoplasmic reticulum (ER). Free ribosomes synthesize proteins that function within the cytoplasm, while ribosomes bound to the ER produce proteins destined for secretion or for incorporation into membranes.
