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- Humans have 23 pairs of these structures, a dog has 78 total.
- A chromosome is created when DNA twists and coils around a histone protein.
- Inside the nucleus of each cell is found a long strand of DNA.
- This DNA is very long, and in fact if you stretched the DNA out it would be around 5 feet in length.
- A chromosome allows the cell to fit all of this genetic material into the nucleus.
- A chromosome consists of a diploid cell consists of two sister chromatids joined together by a centromere.
- Each side of the sister chromatids has the same genetic information as the other sister chromatid.
- During mitosis the spindle fibers attach to the centromere.
- The main job of the centromere is to serve as a place of attachment for spindle fibers during cell division.
- In addition to the sister chromatids, you also have homologous chromosomes.
- Homologous chromosomes have the same genes,but different alleles or copies of the genes.
- You get one homologous chromosome from mom and one from dad.
- This is one reason why you look a little like mom and dad, but not exactly.
What is a chromosome?
Chromosomes