Synthesizing Proteins from mRNA
Translation: The Second Stage of Gene Expression Translation is the process of
converting the nucleic acid code of mRNA into the amino acid code of a protein. It is the
second stage of gene expression.
Structure of tRNA Transfer RNA (tRNA) molecules consist of three stem-loops.
Each tRNA molecule has two functional regions:
1. Anticodon loop: A sequence of three nucleotides that is complementary to an
mRNA codon.
2. Acceptor stem: A single-stranded region at the 3' end where an amino acid is
attached. Enzymes are responsible for attaching the correct amino acid to tRNA
based on its anticodon through a highly energy-consuming process.
Universal and Redundant
The genetic code is universal, meaning it is the same in almost all organisms. It is also
redundant, as more than one codon can code for the same amino acid.
The Ribosome
The ribosome is a complex of proteins combined with ribosomal RNA (rRNA). It consists
of two subunits: small and large. The ribosome has three binding sites for tRNA:
1. A site (aminoacyl site): Receives the tRNA with the next amino acid to be added
to the growing protein chain.
2. P site (peptidyl site): Holds the tRNA with the growing chain of amino acids.
3. E site (exit site): Releases the used tRNA back into the cytoplasm.
Translation: The Second Stage of Gene Expression Translation is the process of
converting the nucleic acid code of mRNA into the amino acid code of a protein. It is the
second stage of gene expression.
Structure of tRNA Transfer RNA (tRNA) molecules consist of three stem-loops.
Each tRNA molecule has two functional regions:
1. Anticodon loop: A sequence of three nucleotides that is complementary to an
mRNA codon.
2. Acceptor stem: A single-stranded region at the 3' end where an amino acid is
attached. Enzymes are responsible for attaching the correct amino acid to tRNA
based on its anticodon through a highly energy-consuming process.
Universal and Redundant
The genetic code is universal, meaning it is the same in almost all organisms. It is also
redundant, as more than one codon can code for the same amino acid.
The Ribosome
The ribosome is a complex of proteins combined with ribosomal RNA (rRNA). It consists
of two subunits: small and large. The ribosome has three binding sites for tRNA:
1. A site (aminoacyl site): Receives the tRNA with the next amino acid to be added
to the growing protein chain.
2. P site (peptidyl site): Holds the tRNA with the growing chain of amino acids.
3. E site (exit site): Releases the used tRNA back into the cytoplasm.
