The Cell Nucleus Flashcards
What are the functions of the nucleus?
Store + maintain DNA DNA replication Transcription Ribosomal biogenesis Control of communication between nucleoplasm + cytoplasm
How is DNA stored?
As chromosomes.
How many chromosomes does a human cell have?
23 pairs.
What are chromosomes made of?
Chromatin = DNA + protein. Protein helps compact DNA strand into chromosome.
What is the centromere?
The place where mitotic spindles attach during cell division.
What is the telomere?
The structures at the end of the chromosome which protect the ends during replication.
Why are there multiple replication origins?
So that replication can take place in a manageable amount of time.
Which 3 features are used to identify chromosomes?
Size, banding pattern and centromere position.
What does metacentric mean?
Centromere is roughly in the middle.
What does submetacentric mean?
Centromere towards one end.
What does acrocentric mean?
The chromosome has one long arm and one short arm.
Which arm is generally longer, P or Q?
Q.
What is a karyotype?
The number and visual appearance of the chromosomes.
What is karyotyping?
The determination of a karyotype, e.g. to detect chromosomal abnormalities.
What is spectral karyotyping?
Where different colour are assigned to each chromosome. Easier to distinguish translocation and other small abnormalities.
What is translocation?
The transfer of part of a chromosome to another position on a non-homologous chromosome.
How are chromosomes organised in the interphase nucleus?
The DNA is decondensed - less tightly packed.
