Cell Nucleus and Protein Synthesis Notes

Nucleus Function

• Eukaryotic cells store chromosomes (DNA) in the nucleus.
• DNA contains genetic information for cell growth and development.
• Genes are transcribed into mRNA in the nucleus.
• mRNA leaves the nucleus to be translated into polypeptides by ribosomes.

Nucleus and Cytoplasm Separation

• DNA is protected from harmful cytoplasmic reactions within the nucleus.
• Transcription (DNA to mRNA) occurs in the nucleus.
• mRNA is modified before entering the cytoplasm.
• Nucleus separates transcription from cytoplasmic metabolism.
• mRNA exits the nucleus for translation by ribosomes.

Prokaryotic Transcription and Translation

• Prokaryotes lack a nucleus, so transcription and translation are not separated.
• Ribosomes attach to mRNA during transcription, initiating translation.
• Eukaryotes undergo post-transcriptional modification due to nuclear compartmentalization, unlike prokaryotes.