Question
Describe the function of each organelle.
Nucleus
Nucleus
Answers
Answered by
GPT-5 mini
Nucleus — main functions and key features
- Stores genetic information: contains the cell’s DNA (organized as chromatin/chromosomes) that encodes all proteins and regulatory RNAs.
- Controls cell activities: regulates gene expression to direct cell growth, metabolism, differentiation and response to signals.
- Site of transcription and RNA processing: DNA → pre-mRNA in the nucleus; splicing, capping and polyadenylation produce mature mRNA; other RNAs (tRNA, rRNA precursors) are also transcribed/processed there.
- Coordinates the cell cycle and division: contains machinery and regulatory proteins (cyclins, checkpoints) that control DNA replication and entry into mitosis/meiosis.
- Nucleolus: a dense region where rRNA genes are transcribed and ribosomal subunits are assembled (rRNA + ribosomal proteins).
- Regulates nuclear-cytoplasmic transport: the double-membrane nuclear envelope with nuclear pore complexes controls selective import of proteins (e.g., transcription factors, histones) and export of RNAs and ribosomal subunits.
- Structural roles: the nuclear lamina provides mechanical support and helps organize chromatin and gene positioning.
Notes: prokaryotes lack a membrane-bound nucleus (their DNA is in a nucleoid). Some specialized eukaryotic cells (mature mammalian red blood cells) lack a nucleus and cannot divide or synthesize new proteins.
- Stores genetic information: contains the cell’s DNA (organized as chromatin/chromosomes) that encodes all proteins and regulatory RNAs.
- Controls cell activities: regulates gene expression to direct cell growth, metabolism, differentiation and response to signals.
- Site of transcription and RNA processing: DNA → pre-mRNA in the nucleus; splicing, capping and polyadenylation produce mature mRNA; other RNAs (tRNA, rRNA precursors) are also transcribed/processed there.
- Coordinates the cell cycle and division: contains machinery and regulatory proteins (cyclins, checkpoints) that control DNA replication and entry into mitosis/meiosis.
- Nucleolus: a dense region where rRNA genes are transcribed and ribosomal subunits are assembled (rRNA + ribosomal proteins).
- Regulates nuclear-cytoplasmic transport: the double-membrane nuclear envelope with nuclear pore complexes controls selective import of proteins (e.g., transcription factors, histones) and export of RNAs and ribosomal subunits.
- Structural roles: the nuclear lamina provides mechanical support and helps organize chromatin and gene positioning.
Notes: prokaryotes lack a membrane-bound nucleus (their DNA is in a nucleoid). Some specialized eukaryotic cells (mature mammalian red blood cells) lack a nucleus and cannot divide or synthesize new proteins.