7.4 Eukaryotic Chromosomes

• DNA packaging 


  • Have 6 billion base pairs and 6.5 feet ( 2 meter)
  • DNA crammed into a nucleus less than 10 micrometers in diameter.
• Chromosomes consist of


  - DNA strands - Histone proteins
• Chromatin


  • the complex of DNA and protein
  • During cell division:
  • Chromosomes condense
  • DNA replicates
  • Chromatin coils tight
• Centromere


  • Region where chromatids are attached
• Chromosome Number


  • The number of chromosomes in a cell. In humans, this is typically 46 chromosomes (23 pairs).
• Homologous Chromosomes


  • Pairs of chromosomes that are similar in length, gene position, and centromere location. One chromosome of each pair comes from each parent.
• Autosomes


  • Any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes.
• Sex Chromosomes


  • he chromosomes that determine an individual's sex. In humans, these are the X and Y chromosomes.
• Karyotype


  • A visual representation of an individual's chromosomes, arranged in pairs by size and shape.
• Diploid


  • Having two sets of chromosomes, one from each parent. Most human body cells are diploid.
• Haploid


  • Having only one set of chromosomes. In humans, only gametes (egg and sperm cells) are haploid.
• In animal kingdom gender has no basis the female could have XY chromosomes and same for the males could have an XX chromosome pairs.