Question

discuss the cellular anatomy for the synthesis and translocation of proteins found in the cytoplasm, nucleus, mitochondria, Endoplasmic recticulum, lysosomes and membranes

Answer 1

The protein synthesis involves the translation of nucleotide sequence of mRNA into the language of amino acid sequence.

Requirement of components include-

1.Amino acids - about half of the amino acids are synthesised by body, the remaining should be suplimented through diet.

2.Ribosomes - these are the sites or factories for the synthesis of proteins.70s type of ribosomes are found in prokaryotes and 80s type in eukaryotic organisms.

3.Messenger RNA - the nucleotide information on the mRNA is translated to proteins

4.Transfer RNA - this caries the amino acids to the growing peptide chain

5. Energy source - ATP, GTP

When the small subunit of the ribosome encounters the mRNA the process of translation begins. The large subunit contains two sites for the incoming amino acids to bind to and thus, be close enough to each other for the formation of peptide bond. The mRNA starts with a start codon and ends with a stop codon , besides the start and stop codon the mRNA also contains regions that are not translated called as the untranslated region.

For initiation to occur the mRNA binds at the start codon that is recognised by the initiator tRNA. The ribosomes proceeds to elongate the amino acid chain called as peptide chain. At the end the release factor binds to the stop codon, terminates the translation process and releases the peptide chain

5.