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- Chromosomes are made up of tightly bundleed DNA strands that are wrapped around proteins called histones.
- Sections of a chromosome that contain thee DNA for specific traits are called genes.
- Chromosomes form a pair of duplicate copiies called chromatids that are joined together by a protein disk called a centromere. (The two chromatids form a shape like a "X")
- Pairs of chromosomes that are similar in shape and size are called homologous.
- Diploid cells (somatic cells) contain hommologous pairs of chromosomes.
- Haploid cells (gametes or sex cells) conttain only one set of chromosomes.
- If a person is born with to many chromosoomes (trisomy) they may cause abnormal development.
- A Karyotype is a collection of chromosomees that can be used to determine abnormalities.
- Chromosome abnormalities can be diagnosedd prenatally with procedures such as amniocentesis and chorionic villi sampling. Both procedures involve taking cells from tissues surrounding the fetus.
- Sex chromosomes carry information that deetermines an organisms sex
XX = females
XY = males
- Non-sex chromosomes are called autosomes..
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