 Human body cells have 46 paired chromosomes or 23 pairs of chromosomes.  Human gametes have 23 unpaired chromosomes  When a sperm and egg unite each parent passes on 23 chromosomes to the offspring resulting in 46 chromosomes in the zygote.  The zygote will divide by mitosis creating the new organism.

 A picture of all the chromosomes in a cell body can be made  Karyotype  Karyotype is set up from largest pairs of chromosomes to smallest pairs.  The first 22 pairs of chromosomes are called the autosomes—they carry the alleles that make up the traits of the body.  The last pair of chromosomes—pair number 23—is the sex chromosomes. This pair will determine the sex of the individual.

 An individual with an XX chromosome pair will be a female.  An individual with an XY chromosome pair will be a male  Karyotypes are usually made to determine if an individual has genes that will cause disorders.

1.How many pairs are seen? 22 full pairs 2.How are they arranged, size wise? Smallest to larges and then the sex chromosomes 3.What is missing in this karyotype? Missing sex chromosome, no additional X or Y (monosomy) Turner’s Syndrome -Infertile -Slow intelligence -No menstruation

1. What is wrong with this person’s Karyotype? 3 sex chromosomes (trisomy) 2. Is this person male of female? male 3. What disorder does this person have? Klienfelter’s Syndrome -AKA as Extra X -Infertile -Learning disabilities -Female body shape

1.What is wrong with this karyotype? Extra chromosome at 21 (Trisomy 21) 2. Is this person male or female? Female 3. How do you know? Two X sex chromosomes Downs Syndrome -generally happy personality -rounded faces -can be male or female -usually sterile -very slow intelligence -greater likelihood of getting diseases; however, very rarely get cancer