Cell nucleus Flashcards
What is the function of the nucleus? [5 marks]
- Storage of DNA
- DNA replication
- Transcription
- Ribosomal biogenesis
- Control communication between the nucleoplasm and the cytoplasm
What is the function of the telomere? [1 mark]
Protect chromosome ends
What is the function of the centromere? [1 mark]
Needed during cell division
G dark chromosomes [4 marks]
- Heterochromatin
- Near centromeres and telomeres
- Highly condensed
- Form 10% of genome
G light chromosomes [4 marks]
- Euchromatin rich
- Active genes
- Loosely condensed
- Form 90% of genome
Metacentric chromosome structure [1 mark]
P and Q arm are of simiilar length
Submetacentric chromosome structure [2 marks]
- Centromere is towards one end
- Longer Q arm
Acrocentric chromosome structure [2 marks]
- P arm is short
- P arm contains repetitive DNA and ribosomal RNA gene
Chromosome organisation in metaphase [1 mark]
Condensed
Chromosome organisation in interphase [1 mark]
Decondensed
Chromosome territories function [2 marks]
- Store DNA
- Control access to DNA
Chromosome territories structure [2 marks]
- Separate chromosome arms and bands
- Non-overlapping domains in the interphase nucleus
Where are gene poor chromosomes located in the nucleus? [1 mark]
The peripheral parts
Where are gene rich chromosomes located in the nucleus? [1 mark]
The interior
Examples of nuclear compartments [5 marks]
- Promyelocytic leukaemia (PML) nuclear bodies
- Spliceosomes
- Nucleoli (making ribosomes)
- Nascent RNA
