DNA packing Flashcards
how big is the nucleus of a cell
a human cell nucleus is 5-8um in diameter and has 2m of DNA
What is the human genome
DNA sequence needed to make a human and is split into 23 pairs of chromosomes
what 2 things can cells be
haploid or diploid
what is haploid
only one copy of each chromosome (23 germ cells)
what is diploid
2 copies of each chromosome (46 chromosomes- all other cells)
how many pairs of chromosomes are there
22 pairs + 1 pair of identical sex chromosomes
what are the sex chromsomes
they give gender- males = XY females = XX
What is Down’s syndrome
3 copies of 21 chromosome
what is a karyotype
image of human chromosome set
what is normal cell division
mitosis and occurs in the M phase
what 3 DNA sequences are needed in a chromosome
telomere, replication origin and centromere
what are nucleosomes
DNA is packed into a cell by winding it around special stool structures (each nucleosome has 8 histone proteins)
what are histone proteins
what nucleosomes are built out of
what are scaffold proteins
where coils of nucleosomes are attached to a protein framework
what are protein filaments
inside and outside and they support the nucleus