What are the steps by which the information in the DNA of the nucleus directs the synthesis of a membrane-associated protein molecule?

Sourav PanSeptember 23, 2024

Answered

The steps by which the information in the DNA of the nucleus directs the synthesis of a membrane-associated protein molecule are as follows:

1. Transcription: The process begins in the nucleus, where a specific segment of DNA (a gene) is transcribed into messenger RNA (mRNA). This involves the unwinding of the DNA double helix and the synthesis of a single strand of mRNA that is complementary to the DNA template.
2. RNA Processing: Before the mRNA can be translated, it undergoes processing, which includes the removal of introns (non-coding regions) and the splicing together of exons (coding regions). The resulting mature mRNA is then transported out of the nucleus through nuclear pores.
3. Translation: Once in the cytoplasm, the mRNA binds to ribosomes, the sites of protein synthesis. The ribosome reads the sequence of the mRNA in sets of three nucleotides (codons), each of which corresponds to a specific amino acid.
4. Amino Acid Assembly: Transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome, where they are linked together in the order specified by the mRNA sequence, forming a polypeptide chain.
5. Post-Translational Modifications: After synthesis, the polypeptide may undergo various post-translational modifications, such as folding, cleavage, or the addition of chemical groups, which are necessary for the protein to become functional and to be properly targeted to its destination, such as the cell membrane.
6. Transport to Membrane: Finally, the newly synthesized and modified protein is transported to the membrane, often via the endoplasmic reticulum and Golgi apparatus, where it can be incorporated into the membrane or secreted from the cell